The Energy Blog

Greenhouse gas emissions – Electric vs Gasoline cars.

Amidst all the scientific studies, academic research and political rhetoric, the debate continues on how much effect converting to electric cars – powered from our existing electrical grid – will have on the emissions of greenhouse gasses – CO2. With the proliferation of these studies, some tracing CO2 contributions all the way back to the first exhalation of breath from the dinosaurs, it can be hard for the average rocket scientist, let alone mere mortal, to come to a conclusion. Therefore, I have decided to shun the scientific calculator, eliminate the variables, and do a simple, empirical analysis of their direct impact.

First, the Coal burning Power Plants.

We are fortunate here in that someone, most likely math challenged, actually had the good sense to measure the CO2 output of power plants. It has been measured and confirmed many times since. Ends up the average Coal burning power plant emits 2.17 pounds of CO2 for every kilowatt-hour it produces. (EIA) Now, coal makes up only 48% of our electrical generation. Natural Gas produces 20% and it also emits CO2 (1.4 pounds per kWh). But, 30% comes from nuclear and renewable sources. So, taken together, our national electrical supply generates, on the high side, 1.51 pounds of CO2 per kWh.

Now for the Cars.

Basic Chemistry tells us that burning 1 gallon of gasoline emits 19.4 pounds of CO2. It also tells us, based on BTU content, there are 36 kWh of energy in that gallon of gas.

One place where all the research gets bogged down is trying to account for the varying efficiencies of our automotive contraptions. Automotive IC (Internal Combustion) engines are anywhere from 15 to 28% efficient in average driving. Well, for our worst case, empirical study, I am going to assume the most efficient – 28%. The most efficient means it is the most work we get for every globule of CO2 emitted. Indeed, the meaning is that 28% of the BTUs in that gallon of gas will get turned into useful, mechanical work. All the rest are wasted as heat. There are 124,000 BTU’s, give or take, in a gallon of gas, so at 28% efficiency 34,720 of them or 10.16 kWh, are actually used for something productive. Yet, we still created 19.4 pounds of CO2 burning that gasoline. A little math, and the emissions result for our car is 1.90 pounds of CO2 per kWh of work produced. Note that at the other end of the scale – at 15% efficiency - those numbers would be 5.4 kWh of useful work, and 3.59 pounds of CO2 per kWh.

Although this article is not about CO2 per mile (remember, simple), for the sake of reference, both the Chevy Volt, and my Chevy Malibu use approximately .240 kWh for each mile at a </i>steady<i> 60 Miles Per Hour. The Tesla Roadster claims to use .217. The Prius is about .220. Your dumptruck, I don't know. However, we do not need to factor in the relative mileage of different vehicles to determine the absolute CO2 emissions potential. Replacing a similar gasoline vehicle, with a similar electric vehicle will still result in similar energy needs.

The answer please!

The results show that burning gasoline in an ICE powered car creates anywhere from 21% to 58% more CO2 than getting the same amount of energy from our electric grid for the same size and shape car. And, that point is important.

The other way many of these studies tend to confuse the issue is trying to relate everything to mileage – like pounds per mile. That is truly putting oranges in an apple barrel. The matter of mileage is irrelevant when comparing similar size and shape vehicles where the only difference is the source of power. They will both use the same amount of energy, which here is expressed in Kilowatt-hours. Regardless of whether they are powered by electricity, gasoline, or soda pop. The difference lies in the source of the power.

Now granted, if you replace your dump truck with a compact car, you will be emitting less CO2, but that is true of either power source, because your small car uses less energy than a dump truck. The reverse would also be true, although good luck finding an electrically powered dump truck.

It should be clear by now that by replacing a gasoline powered ICE vehicle with an electric one, for the same amount of power at the wheels, we would reduce CO2 GHG emissions by anywhere from 21% to 58% - even with our existing electrical supply. And, in fact, those who have bothered to reduce some of the complex, often politically motivated and artistically spun, studies down to their basic conclusions have found exactly the same thing.

A 200 Mile Per Gallon car? The physics of MPG.

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The internet, as well as the local coffee shop, is full of claims of super secret gadgets that will make your car get 200mpg, or 300. The story is always that the only reason we don’t have these fantastic high mileage cars is that “Big Oil” has somehow managed to suppress every single company who has ever tried to make one, or has “bought out” every device that could magically do this to your car.  Well, All of them except for ONE - the person peddling it.

Well, As I have said many times on this blog (and in the coffee shop)  for any particular vehicle it takes a fixed, quantifiable amount of energy to push it around. This is based on the most basic laws of physics, the same laws that give us airplanes, microwave ovens, and, yes, the automobile. So, I’m gonna do it again.

Yes, once more, we will look at how much energy it takes to move your vehicle.  Our purpose will be to define the maximum MPG.

A vehicle will achieve the best MPG or energy efficiency traveling at a steady speed on level ground. In that condition, the only energy it needs is what is required to overcome aerodynamic drag and rolling resistance (friction).

Our test subject for this week will be My Late Model Chevy Malibu, a mid-sized four passenger sedan. It weighs 3,460 pounds, has a frontal area of 24.1 square feet, and a Coefficient of Drag of .37,  Totally Mainstream. To simplify the math, I didn’t do any. I used this calculator: http://ecomodder.com/forum/tool-aero-rolling-resistance.php.

Here is a summary of the results. Remember this is for a steady speed!

Speed	Horsepower	Watts	BTU/min
35 mph	6.15	4586	261
40 mph	7.94	5920	337
50 mph	12.64	9425	536
55 mph	15.66	11677	664
60 mph	19.17	14295	813
65 mph	23.23	17322	985
70 mph	27.87	20782	1182
80 mph	39.12	29171	1660

Before we continue, look at that chart closely. Note how the power required goes up rapidly? Aerodynamic drag is the largest force opposing your movement at any reasonable speed. That drag increases with the square of the speed. Doubling the speed creates four times as much drag. But, interestingly, power requirements increase at the cube of the speed. So that doubled speed will take eight times as much power.

You will also note, I have not mentioned MPG in that chart. It is irrelevant so far.  This chart is the amount of power the vehicle needs. It does not matter whether that power comes from a Gasoline or Diesel engine, an electric motor, compressed air, rubber bands or a hamster wheel.  The amount of force it needs to keep moving is the same.

Also, before we look at MPG, which implies liquid fuels, lets look at the chart and apply it to an electric car. Now it turns out an electric motor is very efficient, turning about 95% of the electricity fed into it into mechanical power. If you look at the 60 MPH row, you will find maintaining that speed requires 14,295 watts of power. To quantify that as energy consumed, or work, we have to add a time element. So, at 60 MPH over the course of an hour, we will go 60 Miles – duh. In that hour we will consume 14,295 Watt Hours of electricity, or 14.2 Kilowatt-hours (kWh). That works out to .236 kWh per Mile. In an amazing coincidence, this is the same as is claimed for the Chevy Volt in electric mode. The Chevy Volt, is indeed, nearly Identical in size to the Malibu.  The Tesla Roadster with a smaller frontal area, and slight better Cd, claims .217 kWh per mile in mixed driving where it’s lower weight is also a factor.

OK, Finally, lets talk about MPG. The calculator I used will give you a MPG figure for each speed based upon the efficiency of the engine and drivetrain. Putting 100% efficiency in it will yield you your 200mpg at 45 mph. (Try it!). At 60 mph, you will get 140 mpg. How did we do that? Well, there are 114,000 BTU’s in a gallon of gasoline, and we are using 813 of them per mile (minute). That is 140mpg with a perfect engine at 60 mph. Right here, we know that a 200 mpg car is impossible at any speed over 45 mph. Even if it were perfect.

Well, sad to say, nothing is perfect. Certainly not your car’s engine.

The Second law of Thermodynamics puts an upper limit on the efficiency of a heat engine. This is known as the Carnot efficiency. A modern fuel injected, steel, Otto cycle, internal combustion engine – the one in your car, can achieve a range of efficiencies from about 15% at idle, to 35% at it’s torque peak and with a wide open throttle. A diesel will achieve the upper end of that range most of the time. What that means, is in the best case, only 35% of the BTU’s in that gallon of gas are being converted to mechanical energy. The rest is wasted as heat out your radiator and exhaust pipe.

The maximum possible Highway MPG my Chevy Malibu can achieve without violating the laws of thermodynamics is thus about 49 MPG at 60 MPH. The only way to improve this number, is to improve the aerodynamics, reduce the frontal area, reduce the rolling resistance, go much slower, or only drive downhill. The Toyota Prius is currently the highest mileage car in the US with a Highway MPG of 48. It achieves this primarily by having a Coefficient of drag of .25, and an estimated engine efficiency of 30% at 65 mph. Try putting these numbers in the calculator and then changing them. Getting the picture?

But, wait, it’s a hybrid. Isn’t that why?

Well, I’m glad you asked. Remember we are talking steady speed. The Hybrid function recovers energy lost through braking. That energy recovered was only the energy we used to accelerate the vehicle. At a steady speed, the hybrid has no advantage over a non-hybrid.  In fact, you will notice the city mileage (stop and go) is actually higher at 51mpg. That is where the Hybrid does it’s work recovering energy.

And, that brings us to our last topic for now – acceleration. My Malibu weighs 3,460 pounds Every time we accelerate that mass to 65 mph it uses approximately 650 BTU’s of energy to do so. Per the laws of physics, that energy is then stored in the mass of the car as kinetic energy until we decelerate (slow down). When we apply the brakes, we convert that kinetic energy to heat which is then lost to the air. This is why stop and go driving normally has much lower MPG numbers.

My Malibu achieves a real world highway mileage of 26 MPG. That means we use a total of 4,384 BTU’s for each mile driven (Remember 75% - 3288 BTUs - are wasted). If we accelerate twice each mile to 65 (using an additional 1300 BTUs), then stop, that consumption will rise to 5,684 BTU’s per mile. Doing the math again puts our resulting mileage at 20 MPG.

I hope I have shed some light on this topic, and on the impossibility of some of the snake oil. While there are various other factors that will change these results in the real world – air temperature, hills, tires, road surface, and specific engine configuration to name just a few, they will not vary by much. And the results for the “perfect” engine will still set a maximum limit on what is achievable.

Ain’t science wonderful!

US Energy consumption.

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I was trying to follow a lecture about energy needs the other day, and make sense of the speaker's numbers. I know most energy statistics, but his numbers were not adding up. I started wishing I had an energy "crib sheet" with simply the big numbers to help me understand. So, I made one. Here it is. This is the amount of energy the US used in October of 2009. I did not make any correlations between units or types, these are the raw figures. Here is this country's overall energy use:

U.S. Energy use for the month of October 2009.

Type of energy	Trillions of BTU's	Millions of Megawatt Hours	Amount
Electricity	1,200	351	Not Applicable
Natural Gas	1,800	527	1.8 Trillion Cubic Feet
Gasoline	1,364	399	11 Billion Gallons
Diesel Fuel	700	205	6.2 Billion Gallons
Totals	5,064	1,482

 (The amount column is the amount of the fossil fuel we used. Electricity is generated by various means. It is an energy carrier, not a fuel.)

Those are BIG numbers. To clarify the units, the totals equal:

5,064,000,000,000,000 BTUs. and 1,482,000,000,000 Kilowatt hours.

If that were YOUR electric bill for October, at ten cents per kWh, the amount due would be: $148,200,000,000.00! That is 148 Billion dollars. Your electric rate may vary.

According to the EIA, on a BTU Basis, the US uses 21% of the worlds energy. So, multiply those numbers by five and you know (roughly) how much the world uses.

One final note on electrical generation.

This country has slightly more than 1,000,000 megawatts (1,000 GigaWatts) of nameplate generation capacity installed. Of that total, about 550,000 megawatts is available at any one time. The rest is down for maintenance, repairs or other factors. There are 720 hours in a month. So we can actually generate about 396 Million Megawatt Hours each month.

Watts, joules & BTUs - What energy terms mean and why.

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Watts, BTUs, joules – oh my. It is easy to get confused with all the different acronyms, and units, being bandied about. Well, In a spirit of pure public service, I am going to try to explain what the different energy terms mean. Hey, I said try…

Although this is not meant to be a first year physics text (there would be much more “between the lines”), before we can understand the units, we must somewhat understand the concepts of work, and force. And how the two are inter-related. We also have to understand what energy is.

Energy:

While energy can be an abstract concept, in our particular context energy means the potential (or ability) to do work. Work is what shifts energy from one system to another. Energy can exist in two general forms potential (stored) or kinetic (in motion). Gasoline contains potential energy. It is just “sitting there” taking up space. Once that energy is shifted to the mass of your car, by doing work – acceleration - the mass of your car then contains energy in the form of kinetic energy. It will contain exactly the amount of energy that was transferred to it.

“It is important to realize that in physics today, we have no knowledge what energy is. We do not have a picture that energy comes in little blobs of a definite amount. — Richard Feynman”

• So, Energy is the ability to do work.

Work:

Now, work seems a simple concept, and it is, sort of. Work, in physics, is of course mechanical work, The moving of something over a distance. If you push your car up the driveway, it is obvious you have done work. Obviously! You have done that work by transferring your bodies’ potential energy into the mass of the car, accelerating the car up the driveway.

But, Interestingly, if you push and push, and the car does not move, according to the laws of physics, you have not done any work. Your energy was expended as waste heat and was not transferred to the car. Physics demands that something be moved for work to happen. Hence no work. Unfair, I know, but that’s the way it is.

You have, however, transferred energy from one system (you) to another (the air) via heat. Well, in thermodynamics, there is another, broader, definition of work. Work can also be defined as the transfer of energy from one system to another. Both definitions are important to the understanding of the terms below.

So work is either the movement of a mass (stuff) over a distance in physics, or, the transfer of energy from one system to another in thermodynamics. The distinction is that in Physics we are dealing with the transfer of energy by mechanical means. In Thermodynamics, energy is transferred, not mechanically, but via heat.
At the risk of being overly simplistic, these are two of the four primary ways that energy is transferred. The other two are electromagnetic waves and gravity. Note there are many defined FORMS of energy – as I stated, energy as a concept is elusive – but it is transferred between systems mainly in these four ways.

But, back to work:

• Work is the movement of a mass over distance, or the transfer of energy from one system to another.

Force:

Force is the influence (or applied energy) that causes work to be performed. When a force acts to move an object, we say that work was done on the object by the force. That force can be electricity, and the object a motor shaft. The force can be chemical energy, and the object a piston or turbine. The force can be gravity, and the object a skydiver falling out of an airplane. Force when applied to a mass (thing) to cause a displacement over a period of time is causing work to be done. In physics, force is mass times acceleration. (F=ma).

• So, force is an influence that causes an object to speed up or slow down (i.e. accelerate or decelerate), or that causes work to be performed.

Power:

And, finally, there’s power. Power is a measurement of how fast that object is speeding up or slowing down, or how fast energy is being transferred between systems. In other words, how much work is being done?  As we all know, the more power we have, the faster the work is done.  Conversely, the faster a certain amount of work is done, the more power is required, and the more power has been used. Power equals work divided by time (P=W/T). Power is an aggregate of all the former terms. It is the measurement of the final result, so to speak, of using energy to apply a force to do work.

• So, if work is defined as moving (accelerating or decelerating)  something, then force is what causes it to happen. Energy is the push behind the force, and power measures how much work has been done.

But, you came here to learn about the units we measure this stuff with, right? Well, if you are still here, we are about done!

“For those who want some proof that physicists are human, the proof is in the idiocy of all the different units which they use for measuring energy. — Richard Feynman.”

We measure the quantity of energy (or force) with the units Kilowatt hour, BTU, or Joule. These are all measurements of “units of energy”.  Conversely, the same units can be used to measure how much energy a process has used. We used so many BTU’s of fuel, so many Kilowatt-hours of electricity, or so many Joules of energy. If energy were water, the equivalent unit would be the gallon.

There are 1055 Joules in a BTU, and there are 3414 BTU’s in a Kilowatt-Hour.

We measure the amount of work that is done with units of power. The Horsepower, the Watt, or the BTU per hour (BTU/Hr). In our water example, these would be equivalent to Gallons Per Hour.

A horsepower is a unit of power sufficient to raise 550 pounds One foot in 1 second. Equivalent to roughly 745.7 Watts, or 2,546.6 BTU/Hr.

There you go! So much background. Well, the concepts I briefly explained (and it was brief) before defining those terms, are extremely important to all fields of energy. They are the foundation principles. The above explanation only scratched the surface.

I will finish this up with a couple of examples.

First with water. The garden needs to be watered with a gallon of water every hour (big garden). This is the amount of energy (water) we need. SO we will be doing work at the rate of one gallon per hour. At the end of ten hours we will have used ten gallons (units) of our energy.

Now lets make the garden a 100-watt light bulb. We need 100 watts of energy every hour to light our room. So we will be doing work at the rate of 100 watts of electrical energy every hour. At the end of ten hours we will have consumed 1 Kilowatt hour (1 unit) of electrical energy.

Our Furnace needs 50,000 BTUs of energy every hour to keep our toes toasty. So we will be doing work at the rate of 50,000 BTUs per hour. At the end of ten hours, we will have consumed 500,000 BTU’s (units) of energy.

Our car needs two gallons of gas (248,000 BTUs) every hour to go a steady sixty MPH. So, we are doing work at the rate of 248,000 BTUs per hour. At the end of ten hours, we will have consumed 2,480,000 BTUs (units) of energy. Of course we ran out of gas 6 hours ago…

I am going to elaborate on that last example, lest you think this is all academic. Simple math tells us that car is getting 30 MPG on the highway. So, how much horsepower did we need from the engine? Well, if you have been attentive, you would realize you divide that 248,000 BTUs by the amount of BTUs in one horsepower and get 97 Horsepower. Right? Well, sort of, but wrong.  In the average gasoline internal combustion engined car, 75% of those BTUs were wasted, they did not make any horsepower. The went out the tailpipe, and kept your radiator warm. SO, the correct way to do it is to take 25% of those BTUs, 62,000 (which is what was actually used to make Power), and divide by 2,546.6.  Which gives us 24 Horsepower. And, that indeed, as a rule of thumb, is what the average 30 mpg car needs to go down the road at 60 MPH.

And, now you know.

Our Natural Gas supply – The numbers game.

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It does not take long to realize that there are more varied predictions on how much Natural Gas this country has, than there are flavors in your local store’s Ice Cream freezer. And, unlike that Ice-Cream, many of the natural gas numbers leave a sour taste in the mouth. Which numbers are correct, which are biased towards an agenda, and which are just plain old pie in the sky – (a-la-mode)?

Now, I am not a geologist so I cannot offer my own independent conclusions, although that does not seem to inhibit many others. What I can do, is to look at those numbers, compare them, and attempt to derive some sensible compromises based on reality, technical awareness, and just plain common sense.

First, lets look at the numbers reported by what are considered by most to be credible and reliable sources. Unlike some, these sources also have facts and figures to back up their analysis.

The United States Geological Survey in their latest report ( Dec 2008) says we have 742 Trillion cubic feet of proved conventional reserves, 378 Trillion Cubic feet of Unproved reserves, and  743 Trillion Cubic Feet of technically recoverable Unconventional resources (Shale and tight gas).
Ref: http://certmapper.cr.usgs.gov/data/noga00/natl/tabular/2008/summary_08.pdf

The Energy Information Administration in Jan 2007 puts US total recoverable conventional reserves at 211 proved  and 373 unproved,  and technically recoverable unconventional reserves (Proved and unproved)  at 1,366 Trillion Cubic feet.  Ref: http://www.eia.doe.gov/oiaf/aeo/assumption/pdf/oil_gas.pdf

Already we have some serious disagreement, although both sources agree on Unproved Conventional gas. The difference in the unconventional reserves likely centers around the definition of  “Technically recoverable”.

The big difference comes in the proven reserves. For some reason the EIA comes up with a very low figure for this, (I did the math 3 times).  Yet, both sources add up to roughly the same total of 1,800 Trillion Cubic feet of reserves.

Now, lets turn to the Natural Gas Association. First of all, they agree with me that there is a wide disparity in these assessments. I feel so good!  They base their own assessment on EIA data as above with total proven reserves at 211 Trillion Cubic Feet, and a total of  1,536 Trillion Cubic feet of unproven reserves.

http://www.naturalgas.org/overview/resources.asp (Very useful page!).

OK. The above references, ignoring what they consider to be technically recoverable, all predicate that we have a total of about 1,800 Trillion Cubic Feet of Natural gas reserves in the  US. Now, I could fill a few pages with references to other reports that “grow” this estimate in leaps and bounds. It all culminated for me in a purported report from JP Morgan Chase that our reserves are NOW 8,000 Trillion Cubic Feet. I have not been able to find the actual report, only references to it. It does strike me that  many of these inflated numbers are coming, not from geologists, or even energy companies, but  from institutions with a financial stake in the trading of Natural Gas. Hmmmm.

I would like to point out also, that there is wide disparity on how much of that gas can be recovered. Certainly not all. According to the Natural Gas association, about 10% of the unconventional. Many sources put it closer to 30 percent. So far shale gas production in the Barnett shale has not lived up to expectations, and they are recovering about maybe 35% of what they thought they would. http://www.aspousa.org/index.php/2009/08/lessons-from-the-barnett-shale-suggest-caution-in-other-shale-plays/

One final issue I would like to address. A common talking point is how many years this supply of Natural Gas will last us. First some baseline numbers. We used 22 Trillion Cubic Feet of Natural Gas last year. That is 1.8 TCF per month, or 60 Billion Cubic Feet a Day!  In the same month we will use about 11 Billion gallons of gasoline,  5 billion gallons of diesel fuel and 342 Million-Megawatt hours of electricity.

Well, if we change nothing, and manage to recover all 1,800 TCF of our natural gas, we are good for 81 years. If we manage to only recover  35%, then about  28 years worth.

But, what if we try to replace our gasoline use with natural gas? That 11 Billion Gallons of gasoline a month is about 1,364 trillion BTUs. Equivalent to 1.3 trillion Cubic Feet of Natural Gas, increasing our consumption by 72%.  If we add in the diesel, that would equal  .65 Trillion more Cubic feet. So replacing our transportation fuel would more than double our consumption of Natural Gas, and reduce our remaining supply to 14 or 40 years, depending on your optimism level. http://www.theoildrum.com/node/5615.

Let’s replace electricity from coal instead. Coal supplies 48% of our electricity, or  164 Million-Megawatt hours a month. Each one has 3.414 BTUs of energy. So, that is 560 Trillion BTU’s. (I checked the decimal point). It would require .6 trillion Cubic Feet of Natural gas to replace our coal. About a 33% increase, assuming the power plant  efficiency is the same – it is close. That would make our natural gas last anywhere from 19 years to 54 years, again depending on how much natural gas we can actually recover.

Finally, I would recommend reading this report on The Oil Drum. It addresses some of these points, and also makes the point that the whole natural gas reserves picture is steeped in unfounded numbers and hype.

http://www.theoildrum.com/node/5676

As for me, I think I will have some Ice Cream.
 

Energy needed by a vehicle (Part 2)

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How much energy does a vehicle need – Part two.

Well. If you tuned into part one, you will know there are basically three things that determine the amount of energy a vehicle needs. The mass (or weight) of the vehicle, (which is only important when it is changing speed or direction), friction drag from the drivetrain - predominantly the tires, and aerodynamic drag – how much the air “pushes back”.

We also learned that it does not matter how quickly the vehicle accelerates, at the end of that acceleration it will have used the same amount of energy to get there, and it will contain the same amount of kinetic energy (momentum). We learned the only thing that effects this is the mass of the vehicle.

I want to make a note right here that the above statement is not entirely true. Remember that aerodynamic drag increases at the square of the speed. While at low speeds this is negligible, as the terminal speed goes up we will have to consume an extra amount of energy in order to overcome this drag. I am going to ignore this for now as the math would only get more complex. That  is simply not necessary to understand the concepts, at least for an automobile at highway speeds. A racing vehicle, on the other hand, is another story…

Also, before we begin, I want to define a few terms.

• Energy is the ability to do work. A Unit of energy is defined by a few different terms. For our purposes they can be used interchangeably.


• BTU (British thermal unit) is a unit of energy. 1 BTU is approximately the amount of energy in a kitchen match. BTU is commonly used to describe the energy content of a fuel.
• KWh (Kilowatt-Hour) is likewise a unit of energy. 1 KWh equals 3,414 BTUs.
• Joule – The metric (SI) form. There are 1055 Joules in a BTU, or 3,601,770 Joules in a KWh.


• Work is the conversion of energy from one form to another (IE: Potential to kinetic). It is measured in ergs, foot-pounds, or, yes, the Joule.


• Power is rate at which work is done or energy is converted (More power=faster conversion) It is measured in watts (SI) or horsepower. It can also be measured in BTUs per hour (BTU/h) One horsepower is equal to 746 watts, or 2,546 BTU/h.


• Force is push. You apply force to cause acceleration. It is measured in Newton’s. 1 Newton = 225 lbs of “push”


• Mass – Mass is the amount of “stuff” something has. It is measured in Pounds or grams (Kilograms).


• Weight You might think this is the same as mass. It is NOT. Weight is the force that gravity exerts on a mass. This concept is important! For example, on the moon, your body will still have the same mass (amount of stuff), but your weight will be 1/6 of what it is here. In the absence of gravity, you will not have any weight, but you sill still have the same mass!

OK. Confused? It takes a while, and a bit of study, to understand the different units of measurement, and what the terms mean. Don’t worry. Just understanding the conversion factors is sufficient for this discussion.

Let me go back to the cereal box once more. The box is the “gas tank”. Inside it we have corn flakes. Those flakes are units of energy (Btu’s or KWh). We have a bowl that will be our Mass. We accelerate that mass by filling it with corn flakes (energy). In order to fill it, we do Work by pouring the flakes out of a hole in the box. The size of that hole – how quickly we can do our work, is called power. Each time a new flake goes into the bowl, we have applied a bit of force, in the form of energy. The more flakes we put in the bowl, the larger the result (speed). I hope that helps, but, now I am hungry.

We had previously determined that a 3000 pound vehicle needs approximately 540 BTUs of energy to accelerate to 65 MPH, on a level surface, and disregarding aerodynamic drag.

So, how much does it need to overcome drag? Well, that gets much, much, more complex. I also cannot write the formula in this blog (or, I don’t know how). The amount of aerodynamic drag on a particular vehicle depends on the shape of the vehicle, it’s frontal area, it’s coefficient of drag (how slippery it is), and, of course, the exact speed it is travelling at. The math gets rather complicated, and it is different for every single different design or shape of vehicle. Since we are talking concepts here, and not a specific vehicle, we simply cannot readily figure this one out. So.

Because of that, I will offer a generic number. At 65 MPH, the average car needs about 30 horsepower to overcome drag. Not very accurate, after all, what is average? But, hey, this is concepts.

Let’s apply that to a practical example calculation. 30 hp equals 76,380 BTUs per hour. A gallon of gasoline contains 124,000 BTUs. A modern car converts about 22% of that (or 27,280 BTUs) to useable power at the wheels. So, 89,100/27280 equals 2.7 gallons of gasoline in one hour, or  24 MPG.

Of course, in the real, practical, world, we are more concerned about things like MPG, and the energy needed to travel a mile (or 100 miles) in a real vehicle. I will wrap up this discussion by looking at some real world examples of energy consumption. And, again, the point I want you to take away is that these energy requirements are independent of the means or efficiency of propulsion.  The energy needs are the same.

So, I will diverge from the theoretical discussion, and discuss what these things mean as relates to our real world use of fuels. There is not room for a detailed examination, so I will just throw some numbers out there. Again, understand the concepts!

The actual amount of fuel that is needed will  depend entirely on the efficiency of the power source. A modern Internal Combustion automotive engine is approximately 28% efficient. That means only 28% of the BTUs in the gasoline are actually used to apply force to the vehicle. The rest are wasted as heat. Since that ICE vehicle needs a lot of gears – transmission, differential, there is also a significant loss of energy (due to friction) before the power gets to the wheels. Estimates of these losses are anywhere from 5% to 12%.  That means, even in the best case scenario, only 23% of the BTUs in the gasoline are available to actually power the car. Many estimate this number to be as low as 15% for real world vehicles.

Compare that to an electric vehicle. Electric motors are better than 90% efficient. Since most times the motors are more directly coupled to the wheels, the frictional losses are also less. That means that maybe 85-90% of the energy stored in the batteries is available to power the vehicle. Remember, the vehicle still has the same energy requirements, and we have to put that energy into the batteries in the form of electricity. Electricity that is simply generated elsewhere.

In the world of electric vehicles, since they are very sensitive to energy consumption, the amount of energy they consume is a readily available statistic. The Tesla roadster is a real world 2700 pound car, powered solely by electricity. According to Tesla it uses .217 KWh (740 BTUs) for each mile traveled. The Chevy Volt is a near real world Plug in hybrid that weighs 3500 lbs, and reportedly uses .250 KWh (853 BTUs) per mile.

For a conventional Gasoline powered vehicle, I use my own 2005 Chevy Malibu for an example. It weighs 3700 pounds, and has gotten 24 MPG over it’s life, mostly in-town. A gallon of gasoline contains 124,000 BTU’s. Applying an 18% total efficiency factor (middle of the range) we can calculate that each gallon is contributing 22,320 BTU’s to actually powering the vehicle. That would mean it is using 930 BTUs, or  .272 KWh. per mile.

What we can see here, is that as the weight goes up, the energy requirement also goes up, but not by much. Remember, the only time that weight itself comes into play is when we accelerate. We can also make the assumption (in fact true) that the Chevy Malibu has more aerodynamic and frictional drag than either the Tesla, or the Chevy Volt, which accounts for much of it’s increased need for energy.

I hope you understand from this discussion what affects the amount of energy a vehicle needs. These are basic rules of physics. It does not matter WHERE the vehicle gets it’s energy from, this is the energy it needs to operate. One more time, that is an important distinction. Whether it is a gasoline, diesel, biodiesel, electric, hybrid, hydrogen, or sled dogs, any particular size, shape and weight vehicle needs a certain amount of energy put into it in order to move you and your stuff to Grandma’s house. And, that, I guess, is my point.

Read part one of this article!

Energy needed by a vehicle (Part 1)

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How much energy does a vehicle use and why?


A vehicle (your car) uses an enormous amount of energy to get us and our stuff around. Some seem to be confused about what those energy requirements are, or how that energy is used. So I thought I would try to clear the air on that subject. I will try to stay away from excessive math. I will also ignore some small details. They are not important to your understanding. My purpose is to explain the concepts. To keep the length under control, this article is in two parts. First we will look at what affects the energy needs of the vehicle. Then, in part two, we will look at the actual numbers, and real world implications. Ready?

There are only four things that effect how much energy is necessary to move your vehicle. The first is the weight (mass, or amount of stuff) of the vehicle. This is important only when we need to change the speed – IE: Accelerate or decelerate. As we shall see though, it is very important for that.

Two others factors are the frictional losses, mostly due to tires, and the aerodynamic drag – how much the air is pushing against the vehicle.

Finally, factor number four,  gravity. Of course it takes more energy to go up a hill (fighting gravity) than it does to go down one (making use of gravity). However, since Gravity would unnecessarily complicate this discussion, we are going to pretend the world is flat, which will then allow us ignore it. With that out of the way, we are left with three things that determine your vehicles energy needs – Mass, Friction, and aerodynamic Drag. So, let’s take a closer look.

First up is the vehicle mass. It takes certain quantity of energy to accelerate a given mass to a given speed. That energy is actually converted from the mechanical energy your car engine (or motor, or squirrel) produces into the kinetic energy, (or momentum), that is then stored in the mass of the vehicle. 

Interestingly, once we are at a steady speed, the mass does not matter (remember, the world is flat, we are ignoring gravity!). Once accelerated, and at a that steady speed, the vehicle’s mass possesses all the energy that was put into it while accelerating as kinetic energy – also known as momentum. And, it will continue to travel at that speed  using no further energy, unless acted upon by another force. Indeed this is how our interplanetary spacecraft operate, it is how our space probes go on for years without needing any fuel. Unfortunately for us though,  here on earth there are two other forces that exist to complicate our lives.

So, next up we have friction: Friction is always present (there is no perfect system). In a car, in addition to the bearings and gears, the primary source of friction is the tires against the roadway. Now, this is can be a good thing because that friction, going by another name – traction, is what keeps your vehicle going in the right direction! But, when considering energy, as long as the vehicle is moving it is having to overcome that friction, using some amount of energy in the process. Friction is always trying to slow your car down by removing kinetic energy from it. That means we have to continually add that energy back to maintain the same speed.

And, the last factor is aerodynamic drag. Any time your vehicle is moving, air is pushing back, trying to slow it down by removing the kinetic energy from it. Again, the same as for friction, we have to continually add energy to the vehicle to maintain a constant speed. This is literally the amount of energy needed to “shove” the air out of the way.

A quick fun factoid: Aerodynamic drag increases with the square of the velocity, however, the power (force) needed to overcome aerodynamic drag increases with the cube of the velocity. So, if you double the speed, there is four times as much air pressure pushing against you. To overcome that drag will require eight times the power (2x2x2). A car going 50 mph may require only 10 horsepower  to overcome aerodynamic drag, but that same car at 100 mph requires 80 hp!

Another fun fact. As you can ascertain, when travelling at a fixed speed, the mass (weight) of the vehicle is of little concern. A heavier vehicle will cause more frictional losses (tires are squished more), but, if they are the same size as far as aerodynamic drag is concerned, it doesn’t matter if your vehicle weighs 2000 pounds, or 200,000 pounds it will take the same amount of energy to keep it going. Once in motion, it stays in motion until an outside force acts on it – in our case, friction and aerodynamic drag. This is the reason railroads are incredibly efficient. For their weight, they have very little frontal area (aerodynamic drag), and since the wheels are steel, on steel tracks, they have much less friction than a road vehicle with rubber tires. Of course, a train also does not start and stop very much.


There it is. These are essentially the ONLY things that effect the amount of energy your vehicle needs! (Note, for the physicists, I did say essentially!). Once again, they are: The energy needed for acceleration, and the energy necessary to overcome mechanical friction and aerodynamic drag.

As to how much energy. Well, there is a very fixed requirement for the amount of energy needed to accelerate a mass. Issac Newton told us so! The larger the mass (more weight) the more is needed. An important point here: It does not matter how quickly you accelerate.  The amount of energy needed and consumed to accelerate a specific mass to a specific velocity is the same. This is true whether you impart it quickly to get to a certain speed, or if you take your time to attain the same speed. In the end, the same mass at the same speed will contain the same amount of kinetic energy (momentum). The formula is kinetic energy = ½ times mass times velocity squared. And, note that the velocity is squared. So, to go twice as fast will require adding four times as much energy to the mass.

Now, you are probably wondering about Power. Specifically Horsepower. What role does it play? Well, we know that to accelerate a specific mass to a specific speed, we need to impart a specific amount of energy into it. Is that specific? If we have “more power” defined as the capacity to do work, we can impart that energy to our mass faster. That means we will achieve our velocity quicker. But, we have used the same amount of energy. We have simply put that energy into our mass quicker, and for a shorter period of time.

Think of a box of cereal. The box is our energy source (gas tank). Inside that box are individual corn flakes. Each flake is a BTU of energy. In order to achieve a certain speed we need to transfer all of the flakes inside that box into our bowl (our vehicle). If we make a small hole in the top of the box, we can pour a certain amount of flakes through that hole. With a small hole, it may take us 30 seconds to pour them all into the bowl. If we make the hole twice as big, we can pour them out twice as fast, and achieve our objective (speed to breakfast) twice as fast. Well, you’ve hopefully figured it out by now. The hole is our engine, and the size of the hole is the power that engine has (HP-Hole Power). Bigger hole (power), quicker result. But, note, we have transferred the same exact amount of flakes (energy from the gas tank) to achieve our goal, no matter the size of the engine (hole). We just did it quicker!

OK. Hopefully you now have some idea of the factors that affect your vehicle’s energy needs.

But, before we go on to part two, just for fun, lets figure out how much energy we need to accelerate a typical 3000 pound (1360 Kilogram) car to 65 Mph (29 Meters per second). We will use the  formula for momentum. Once again, it is:  Momentum = the mass (in kilograms) times the square of the velocity (in meters per second), divided by 2. The result is the number of Joules needed.

29 squared is 841 times 1360 = 1143760/2 = 571,880 Joules. As we will learn in part two there are 1055 Joules in a BTU. So, we used 542 BTUs of energy to accelerate the car.  Doesn’t sound like much? Well, we will get into that in part two. Stay tuned!

On to part two!

The cost of driving with your headlights on

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I was having one of “those” conversations the other day. You know the ones that sound silly at the time, but make you think about it later. This one was about driving with your headlights on during daytime. A number of people had reasons they refused to turn on their headlights until it was too dark to see. I argued then that the reasons were unfounded, but I decided I should prove so. This is only “sort-of” about energy, but…

Before I begin – let me say this is a safety issue. You turn your headlights on in inclement weather, or during the daytime, in order to better be seen by other drivers. And it works. Any number of studies have shown that Daytime running lights significantly reduce accidents – especially the nasty ones where someone turns in front of someone. That is why they are required on motorcycles, and why many, if not most, other countries mandate daytime running lights.  OK, Enough with the safety lecture.

One argument was that it “wore out the battery”.  No. As long as the engine is running, your alternator is supplying power to all the electrical accessories. The battery is only for starting (and running the radio at drive-ins – you remember those). With the engine running, the battery plays no part in supplying electricty. In fact, once the engine is running you can completely remove the battery without any problems. Now I DO NOT recommend that in a modern "electronic – mobile" for other, unrelated reasons, but on an older car, it is perfectly fine.

The other argument was that it reduced gas mileage. And I agreed, but only by an extremely tiny, insignificant amount. Since as you know by now, I like all these numbers, I decided to figure out how much.

Well, the headlights do take power, energy. And we know that energy HAS to come from the gas tank since we do not have warp plasma reactors in our cars. In a typical sealed beam setup, the headlights draw 55 watts each on low beam (Halogens are similar). This means both headlights draw 110 watts (about the same as your table lamp). The taillights are also on, and draw 7 watts each for 14 watts total.

So, when we turn our headlights on, we have increased the electrical demand by about 125 watts (BTW, that is 10 amps at 12 volts). This would be equivalent to setting your heater blower on medium, but, I digress.

Since there are way too many variables to come up with a general number for all driving conditions in such a basic discussion, I will concentrate on one condition. We will say you are driving down the road at a steady 60 MPH with your headlights on. You take a trip of two hours (120 miles) and you get 30 mpg during the trip. So, in that 2 hour trip:

You have burned four gallons of gas. That is 496,000 BTUs (A measure of energy content). Your headlights have consumed .250 (point 250) Kilowatt-hours of electricity. At 3,414 BTUs per KWh, that is 853 BTUs. Now, that electricity was made with an engine that is 25% efficient, so we actually used 4 x 853 = 3,414 BTUs of our gasoline’s energy content to run the headlights.

.68 percent of the total energy in that four gallons of gas was used to run the headlights. Which is, in essence, how much your mileage would have increased if you had turned them off. Point 68 percent, which is .2 MPG at 30 mpg. At $2.50 a gallon, out of ten bucks worth of gas, you spent  3 and a half cents to turn on your headlights.This is not absolutely, incredibly, accurate (the many variables thing), but close enough for our purposes. It surprised me a little bit, the .2mpg thing,  but I still say it is well worth it.

Now, you know….

Making oil out of a Sow's rear - converting pig manure to oil.

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I just read an enlightening article about a new source of potential energy,  It seems that scientists at the University of Illinois have developed a process for converting raw pig manure into crude oil.  They go on to say that with further development, the process may even yield biodiesel. Now the actual research was published in 2006. It apparently has taken this long for someone to put this newfound technology to use – making roads.

Now, in case you don’t know, let me bring you up to speed on the US pig industry

According to the US Department of Agriculture in 2007 there were 67.8 Million pigs in the United States. On average, those pigs take up space at the rate of about 8.7 per acre. And those pigs produce about 8 pounds of waste a day. That is a lot of pig poop - two and a half tons a year!

This procedure promises to make a half a barrel of oil substitute (21 gallons) per year out of that 8 pounds of daily pig manure using a thermochemical conversion (TCC) process. How much water or energy is involved in the process (and there is some of both) is unclear.

Now, one of the original sub-licensees of the process, Innoventor Inc., a design and engineering company, is going to use the process to make asphalt pavement for a road leading to Six Flags St. Louis.

This is great news. Any waste that can be successfully re-purposed is not only good for recycling, but good for conserving energy. Not a whole bunch, but, hey, it all counts.

According to the researchers, each pig can produce one half a barrel of oil substitute (21 gallons) per year. With 67 Million pigs contributing, that would be 33 Million barrels per year. –  About three days worth of US Oil imports. OK, it won’t wean us from oil. That would, however, keep us in asphalt for about 100 days. And it would eliminate a big problem for pig farmers, as well as put a few more dollars in their pockets.

And it could be a win-win for the country. We all love Bacon, hate pig poop, and need oil.

Here is the article that spawned this one.

http://www.stltoday.com/stltoday/business/stories.nsf/story/8BD4ECDDEBD84EC686257706000C0410?OpenDocument

Here is a recent article from Water & Wastewater about the process.
http://www.waterandwastewater.com/www_services/news_center/publish/article_002060.shtml

Here is an article from National Geographic about the process.
http://news.nationalgeographic.com/news/2004/07/0701_040702_pigoil.html

And, here is the original research report news item.

http://www.aces.uiuc.edu/news/stories/news3557.html

And finally, here is a place you can read the original research paper OnLine!

http://www.docstoc.com/docs/20627967/THERMOCHEMICAL-CONVERSION-OF-SWINE-MANURE-AN-ALTERNATIVE-PROCESS-FOR

Well, that'll be a "wrap" with bacon and ham.

Vertical Axis Wind Turbines - A case study (Windspire)

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VAWT – The good, the bad, and the Windspire Small Wind Turbine.

I came across this unit recently, and it caught my interest. It would appear that it solves a lot of problems related to small-scale wind power. It is aesthetically “pleasing”, easy to install, self contained, and claims to produce a significant amount of power. Unfortunately, like many of its peers, it does not live up to the promise. I still like the Windspire. I hope they resolve some of the problems. It is a neat concept, and a company that appears to want to make it a success. They have numerous installations already, and I wish them the best of luck. However, I am going to take the opportunity to point out some of the challenges that the Windpsire, and most other VAWT designs, encounter. This is not an indictment of the technology, nor of this particular example. It is, just that, an example to be used for education. I believe strongly in large scale wind power. I do not think small scale is ready for prime time. However, by addressing some of the below issues, it can possibly move closer to reality.

The Windspire  HAWT from Mariah Power.
 


Unfortunately, the Windspire website is devoid of much actual technical information – at least that I can find. Neither can I find much information from their installed base. However, I did find that the NREL (National Renewable Energy Lab) tested the Windspire, and produced some useable data. I want to point out, this data is preliminary, done with an early example. If you look at the report, Windspire answered the NREL findings, and described the ways they are addressing some of the findings. Where that process is right now, I do not know.


So, first, the Windspire description. A VAWT (Vertical Axis Wind Turbine) with a maximum output of 1.2 kilowatts. It is capable of direct connection to the grid, and making use of net metering. The reported minimum wind speed is 8 Mph (Defined as a class 3 area). Best I can tell, the purchase and installation is in the range of $6,000 to $10,000.  This price range puts it on a par with the cost of installed Small scale (residential) Solar PV (PhotoVoltaics), albeit before any of the tax credits or incentives Solar is eligible for. I do not know how those credits would apply to Wind.

Here are the NREL testing results: Be sure to read the response letter from Mariah Power in the first link. It is apparent they took the results seriously, and they were proactive in addressing them.

Overview: http://www.nrel.gov/wind/smallwind/pdfs/mariah_report.pdf
Performance: http://www.nrel.gov/wind/smallwind/pdfs/mariah_power_performance_test_report.pdf
Main Testing page: http://www.nrel.gov/wind/smallwind/independent_testing.html


Wind Speed.

Alas, a problem that seems endemic to all small wind turbines, be they Vertical or Horizontal Axis,  is the need for speed – wind speed. Do not believe output claims. The typical wind turbine, in the typical wind, will put out but a fraction of the amount of electricity it claims to. While the NREL results with this particular model are telling, the story they tell can be applied to most, if not all.

Below is the output data  for the Windspire from their web site. Note that it does not produce any usable power at less than 8 mph – it’s stated cut-in speed. At 12 mph it is still producing less than 100 watts (1/12 rated power). It reaches half it’s rated power output, 600 watts in a twenty MPH wind, and does not reach full specified output (1200 watts) until the wind is “howling” at 24 Mph.

http://www.mariahpower.com/testing.aspx

Now, as I said, this seems to be true of most wind turbines, and especially of the VAWT designs I have seen. They need a lot of wind to produce usable amounts of electricity. By perusing average wind speed charts, it can be seen that this high cut-in speed limits the viable areas to a fraction of the US, mostly in the western plains and coastal areas.  Operating at half it’s output rating (20 MPH average winds) it would need to be in a class 5 area on the below chart. As well, the wind is intermittent. This is the average wind speed. Another thing we have to take into consideration is the capacity factor – what percentage of capacity is actually produced. All power sources have a capacity factor. Below I have provided a link to an explanation as related to wind. For a wind turbine of either design, the capacity factor is about 30%. The machine will produce about 30% of what is the calculated maximum. For the above situation, 20mph average, the annual output would be 5,256KWh per year times 30%, or 1,576 kWh per year . About 13% of the average annual US household electricity usage. (Per EIA Data). That is not bad, if you live where the wind blows! At the average electric cost of 11 cents per kWh, that would save you $174.00 per year. That makes the break-even point (at $6000 installed cost) at about 32 years. Oops, didn’t mean to be negative!



Here is a chart of the average annual windspeeds throughout the US.

http://www.windpoweringamerica.gov/pdfs/wind_maps/us_windmap.pdf

If you ever wondered, and you have a flagpole nearby, you can somewhat estimate the strength of the wind. Note that on the Beaufort scale used in the below link, you would need a level 3 wind (Flag flying almost straight out) before any of these small turbines would even start to produce usable power. And, at even half power, the  poor flag would be “stiff as a board”. What is YOUR flag doing?

http://www.redwitch.com/extras/flag_wind_speed.aspx


And, here is that explanation of capacity factor I promised.

http://www.ceere.org/rerl/about_wind/RERL_Fact_Sheet_2a_Capacity_Factor.pdf
http://en.wikipedia.org/wiki/Capacity_factor


This link will take you to the specifications of a popular HAWT – The Skystream. It is twice the “size” of the Windspire. Most residential wind turbines are similar.

http://www.talcoelectronics.com/wind-manuals/skystream-specs.pdf

Here is a classroom project that contains power curves for several popular small wind turbines

http://www.kidwind.org/PDFs/LESSON_windpowercurves.pdf


Finally, here is a very interesting, albeit older, article about small wind turbine outputs. The author undertook to test a number of turbines with some revealing, if not unexpected, results.

http://www.wind-works.org/articles/PowerCurves.html




I also want to address Fatigue

A VAWT endures a lot of stress. The bad kind of stress. Repeating and reversing stress. Much more than a HAWT.  Many of the problems the Windspire encountered at NREL were due to poor stress management – in the turbine design, not necessarily in the creators.

 In a horizontal (propeller) turbine, the force of the wind is always from one direction, and pushes the blades in one direction. This stress is transferred via a thrust bearing directly into the tower structure. Propeller blades are a mature technology, and it is well understood how to make them withstand this type of stress. The direct, compressive nature of the force transfer to the support structure is also well understood, and  easy to implement. HAWT’s themselves do not often suffer failures from imposed wind loading.

In a VAWT, on the other hand, in every revolution of the blade structure the wind load reverses. First the blade is pushed one way, then the other. This creates fatigue. If you have ever bent a coat hanger back and forth until it snaps in half, you understand the process. This is not an easy thing to overcome. Some have tried – unsuccessfully – to address this with complex mechanical linkages. Complex and mechanical are not two words you want associated with something that is supposed to have a long lifetime. I want to touch briefly on the effects of these stresses, and the failure modes. While this is based on the NREL experience with the windspire, the principles apply to all.

As any structural engineer knows, you do not try to resist these forces, you absorb them by moving in a carefully defined way, and by spreading those forces out over as much of an area as you can. Trying to create a structure that will physically, with brute strength, resist these loads results in an incredibly massive structure. The bridge or building will collapse under it’s own weight, and the airplane would never get off the ground, let alone carry anything else. A wind turbine would be too heavy to move, and too massive to support (and cost even more of a fortune). It is much more practical, and in most cases necessary,  to go with the flow, than to fight against it.

If you take that same coat hanger we mentioned above, put your hands at the very, outer, ends of the hanger, and try to break it, you will find the task much more difficult, if not impossible. The stress you are putting on the hanger is no longer concentrated, it is spread out over a large area – the span of the wire.

It would appear the designers of the Windspire forgot this principle. To their credit putting it in practice is a tough job. Their test article at the NREL met with a number of fatigue failures. Interestingly enough, the primary place that these failures were concentrated in was the welded joints.

Now, about, welding. The joints on a VAWT have to be strong, and light. A welded joint does not lend itself well to this. If you look at bridges, large buildings, and Airplanes, you will find they are bolted (or riveted) together. Indeed, all of those structures are designed by people who know a lot about stress and repetitive reversing fatigue– especially airplanes. They learned long ago that you bolt the joints together. Rather than concentrating the stress in one, weak, spot, a bolted joint distributes that stress equally over the entire area. In effect, a bolted joint “gives” a little.

In their answer to the NREL test, it would appear the Windspire folks have learned that lesson, finally. The replaced a number of the failed welded joints with bolted ones. Hopefully this will eradicate some of the problems. I hope they also learned you need more than one engineering discipline to design something like this… Airfoils, electrical, mechanical, AND structural.

The other major source of stress in a VAWT is literally at the bottom. All of the bending loads that are imposed on the rotor are transferred to the bearing at the bottom. A critical, single, point that needs to not only resist all of these forces, but needs to turn freely at the same time. This is one of the major obstacles to engineering a VAWT, and one that especially challenges homebuilders.

Here is an interesting “PowerPoint” presentation on Wind Turbine design from Cornell.

http://cfd.mae.cornell.edu/~caughey/WindPower_09/Presentations/Lyons.pdf


Electronics

Finally, I truly do not understand why the Windspire suffered so many electrical problems, mainly with the inverter. Inverters are a mature technology. Many millions are happily and quietly puttering along converting DC Power to AC.  My guess would be that either they need another electrical engineer on the team, or that they tried to cut corners by making the inverter components just sufficient to do the job – in theory. This is not good engineering or good marketing, practice, especially in something so critical to the success. The cost of properly over-sizing the electrical components is very small compared to the cost of the unit, but the failure of these components exacts a high cost in their reputation. Hopefully a re-design will put these issues to rest.


Well, from the length of this post, It would appear I have overstayed my welcome. These are but a few of the challenges facing wind turbines. I will address others (and perhaps the same ones) from time to time. Eventually we will get there. Perseverance, patience and a commitment to putting one foot in front of the other. For now, I will maintain my belief that our best path leads to Large-Scale Wind power, and small scale Solar. But, who knows. I wish Mariah Power the best of luck, I will be watching.

Hydrogen Snake Oil - Part 1. The myth of a hydrogen economy

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Hydrogen Snake Oil – Part 1 – Making Hydrogen.

As it was with the snake oil salesmen, and often is with our politicians, we are being sold a bill of goods, and a panacea solution to a very real problem. The problem is our insatiable thirst for energy, and the solution is The “Hydrogen Economy”. While it is being sold as a “futuristic way” to solve our energy problems, I am going to offer my opinion here that it is deflecting our vision and efforts from more serious and realistic goals.

Hydrogen as a transportation fuel is fraught with technical problems. Serious and debilitating problems …..

The first problem is that hydrogen is NOT a fuel at all. It is an energy carrier, the same as electricity. For every watt, BTU, Joule, or gigadyne that we get out of hydrogen, we have to put at least that much into it. And, since in the real world of physics there is no free lunch, we actually have to put in much more.

Free hydrogen does not exist on this planet. We cannot drill for it, mine it, or make a magic box that will spit out limitless amounts of it. We have to manufacture it. This is not a trivial task. Hydrogen has an affinity for just about everything. It binds to carbon to create hydrocarbons – our fossil fuels, and it binds with oxygen to create water – the substance of life. In order to manufacture it we have to break those bonds – and then, akin to keeping a pack of wolves separated - we have to keep it from re-bonding with what it likes until we can use it. So, we will stop calling hydrogen the “fuel” of the future. If anything, it is the energy distribution system of the future, although I seriously doubt that.

This essay will be in four parts. The first part will look at how we manufacture hydrogen, the second will explore how we transport and store it, and some of the challenges that entails. I will devote the entire third part to using hydrogen in our vehicles. Finally, in  part 4, I  will explore what is really behind this deception, (did I mention money?), describe the one or two, utopian, scenarios where hydrogen COULD be a viable energy carrier, and take a brief look at the state of the hydrogen art today.

There are currently two major ways to manufacture hydrogen today. The first is via that again futuristic sounding process “electrolysis”. It is really simple, you may have done it in a science class. Many more are doing it to generate small amounts of hydrogen, and large amounts of cash. We take water, pass an electric current through it, and out comes hydrogen at one end, and oxygen at the other. It IS that simple.

But, wait, did I mention “pass an electric current”? Therein lies the rub. We need an electric current. A large electric current. Ignoring a little bit of heat energy we need, we also have to input at least as much energy (BTUs) in the form of electricity into the process, as there will be energy contained in the hydrogen that comes out.  In fact, in actual practice, the most efficient processes operate at about 70% efficiency. So, we have to input 30% more energy than we get out.  So here is our real world, 70% efficient formula for getting hydrogen from electrolysis.

Water – plus -  48 Kilowatt-hours (KWh) of electricity = 1 Kilogram of hydrogen and .5kg of oxygen.

Let’s put that in perspective. 1 Kilogram of hydrogen is 11.1 Cubic Meters (392 Cubic Feet) at atmospheric pressure. That amount of Hydrogen contains 125,000 BTUs – About the same as a gallon of gas. About the same as 37KWh of electricity. We put 164,000 BTUs into this process via electricity. We recovered 125,000 BTUs out. What we have done, so far, is to WASTE 11 KWh of electricity to manufacture a substance that contains the same energy as one gallon of gasoline. A substance that takes up over 3000 times as much space as that gasoline, and, a substance that still has to be distributed, stored, and used in some way to power a vehicle, complete with many more significant losses along the way.  And that is with a very efficient form of the process. Many electrolysis cells only obtain 50-60% efficiency.

Consider briefly, that same 48KWh of electricity, applied to a current, viable, production EV like, say,  the Tesla Roadster  (at .217 KWh/mile) will  take you about 221 miles down the road. In style, comfort and at a high level of performance.  How does Hydrogen compare in a vehicle? Well, we will address that thoroughly in part 3. Hint  – not very well… But, back to our supply discussion.

The fact is that electrolysis, in addition to it’s energy losses, is not a cost efficient way to create hydrogen.
Because of this, virtually all the industrial and commercial hydrogen in this country, and in the world, is created by another process. Steam reformation of natural gas (Specifically the methane that constitutes 80-95% of natural gas).

Did I say Natural Gas? Why yes. The most common and cost effective way to manufacture hydrogen is by converting a fossil fuel. A non-renewable hydrocarbon resource.

It turns out, if you heat natural gas to a hot enough temperature, and pass it through a catalyst, the chemical bonds holding the hydrogen and carbon together are broken. We get hydrogen out one end, and carbon, in the form of both carbon monoxide and carbon dioxide, out the other.  The heat is about  900-1000 degrees Celsius, that’s 1800 degrees Fahrenheit for us Americans. The catalyst is a precious metal, like platnium.

If you remember, all the energy we hope to eventually get from our hydrogen has to be put into it to “make” it. Plus a little – actually a lot – more to allow for the process losses. The energy we put into the steam reformation process is primarily the BTU (energy) content of the natural gas feedstock.

In addition to the natural gas, we also need the afore-mentioned heat, to make steam, to make the process work. Well, fortunately, a steam reformation process can make use of waste energy (energy not put into the hydrogen) to make that heat, improving the overall efficiency of the process from poor, to sort of good.

And, just what is that efficiency? For a typical large SMR (Steam Methane Reforming), the energy efficiency is quite high – 80-87%. Of course, throw in extensive maintenance requirements, the regular replacement of expensive catalyst material, and a little bit of electricity to run all the pumps and compressors, and the economic efficiency suffers quite a bit. But, in our non-economic model , we don’t care about that. So, here is the result from an actual plant:

We put in 141 Cubic Feet of Natural Gas, we get out our 1 Kilogram of Hydrogen. 144,000 BTUs of natural gas in,  125,000 BTUs of hydrogen out. MUCH better than electrolysis – which is one reason this is the preferred method.

(Of course, we could have just burned that Natural gas in an existing Natural Gas Vehicle and saved the losses, but again, that is for part 3… Sorry.)

But, wait, there’s more. Remember I mentioned one of the products was carbon? Well, since we started with a hydrocarbon (natural gas), if we take out the hydrogen, we are left with the carbon as a byproduct. Indeed, steam reformation produces the same amount of carbon emissions as would have happened had we just burned the natural gas. So, Will Robinson, we have another problem, one of the ones we have been trying to eliminate with all this alternative energy stuff – Carbon emissions. To be fair, they are much easier to trap and sequester here than in, say, a coal burning power plant. But deal with them we must. More cost, complexity, and another hit on hydrogen’s ever-poorer performance.

Just a short word about Steam reformation in a sensible recent quote from the US DOE (energy.gov)

“DOE is not funding research activities for large-scale central production of hydrogen from natural gas. DOE efforts are focused on distributed natural gas reforming for the transition period only. Large-scale hydrogen production from natural gas reforming is a mature technology, and natural gas resources in the United States are limited—15% of the natural gas we use is imported. Producing large amounts of hydrogen from natural gas in the long term would only trade U.S. dependence on imported oil for U.S. dependence on imported natural gas.”

 I also would like to point out that, to my knowledge, all of the ballyhooed methods of producing hydrogen from things such as biofuels, or biomass, depend on steam methane reformation as described above.

There are a couple more exotic ways to create hydrogen. But, no matter the method, the basic laws of physics say we not only have to put as much energy into it as we get out, but, because no process is perfect, we have to put in more. Believe me, there are no “magic boxes”. magic catalysts,  or free energy processes. Indeed, if there were, they would violate a number of fundamental laws of physics and thermodynamics. While some might argue – well we don’t know everything (and they would certainly be right) these are BASIC, well proven and accepted laws of science. The chances are mighty slim.

And, so finally, I do want to mention one other way that we can conceivably produce hydrogen. Coal Gasification.

The first thing we do is make syngas (town gas) from coal. We do that by injecting oxygen and water into a reactor (the gasifier) under high heat and pressure. The output of this reaction is a mixture of carbon monoxide and hydrogen (the syngas). We can then put that gas through the same reformation process as above and get hydrogen and carbon dioxide out. Yes, it produces nearly the same amount of CO2 as if we had burned the coal. Amazing how these things work out.

Coal gasification is really a subject for another article. While the process is being examined for the production of syngas (and gasoline via the Fischer-Tropsch process.), it is quite controversial, and in the very earliest stages of research. This article is about hydrogen, and to my knowledge there are no serious considerations of making transportation hydrogen from this process. It is dirty, inefficient, produces a number of toxins, and is still using a non-renewable fossil fuel (that, incidentally, we rely on heavily for our electricity).

I will write that article soon. In the meantime, here is a link to more information on Coal Gasification:

http://en.wikipedia.org/wiki/Coal_gasification

That’s it for part one. Stay tuned in the upcoming week or two for parts 2, 3 and 4. There is much more to cover, and many, many, more challenges facing that hydrogen economy. We have just scratched the surface.

I know you can’t wait.


Reference conversion factors;
1 Gallon = .133 Cubic Feet
1 KWh = 3414 BTUs
1 kg Hydrogen = 1.003 GGE (Gallon Gasoline Equivalent)
1 kg Hydrogen = 392 Cubic Feet at 1 atmosphere.
Tesla roadster reported energy usage is .217KWh per mile. Or 4.7 miles per KWh.

Smart Grid Benefits

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It is my opinion that a key part of our conversion to renewable energy will be the improvement and enhancement of our national electrical grid. In it's current form, our grid is incapable of managing, or utilizing, a large amount of energy developed by wind, solar, or other alternative means. Currently the supply and demand of electricity has to be carefully balanced in a real time, second to second manner. Without the ability to control the outputs of these distributed generation sources, and without the ability to blend their output into existing sources, we will never be able to realize their full potential.

In my opinion, our future lies in distributed generation of electrical power from all types of renewable and environmentally sound sources - wind, solar, residential solar, hydro, biogas fuel cells, tidal, ocean thermal, and more. All can contribute electrical power to our national grid.

Our national electrical grid will then distribute the combined power from all these disparate sources to our homes, offices and factories. Electrical power can then be utilized in plug-in hybrids and electric vehicles for our transportation, electric buses, trains and monorails for urban transit,  and a thousand other things we use in daily life - even our lawn mowers.

Smart grid is the overall moniker applied to various changes to today's grid and it's technology to allow better energy management, control and measurement. Implementation of Smart Grid technologies, strategies and methodologies is an important early step in sustainable energy.

This paper is an excellent overview of both our existing electrical distribution, how smart grid will change it, and the effects that change will have. It is not light reading, but, once you get past the introduction, I think you will find it interesting and informative.

So, get a fresh cup of whatever, sit back, get comfortable and check it out... Don't forget the munchies.

http://energyenvironment.pnl.gov/news/pdf/PNNL-19112_Revision_1_Final.pdf

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Ten steps to a better energy future.

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Last year this country used 4,110,259,000 Megawatt-hours of electricity.  23.2 trillion cubic feet of natural gas, and  7,117.5 Million Barrels of oil. All of this went to supply our never ending thirst for energy. We are an energy happy society. Seventy percent of that electricity was generated by fossil fuels – Coal and Natural Gas. Seventy Eight percent of the Oil we used went to move us, and our stuff, around – transportation. In fact, over 85 percent of ALL our energy came from non-renewable, finite, fossil fuels. Only 7% came from renewable or replaceable sources. The rest came from nuclear generated electrical power.

It is simple common sense that we cannot go on like this, even without the average annual 3.4% growth in energy consumption. Fossil fuels were created millions of years ago, after mass extinctions of animals and plants. Over those years, sediment built up over the dead matter, which rotted, and then, under mounting pressure from the built up layers of sediment, became the Oil & Gas we use today. So far, in just the last 100 years we have consumed well over half of the known or suspected Oil on this planet. We have consumed well over 1/3 of the known Natural Gas and Coal.  Much of what is left of all of these resources has to be recovered by ever more complex, challenging, expensive, and time-consuming methods than were used previously. At this rate we will be completely out of obtainable fossil fuels well within the next 100 years. And, to get any more, the earth will have to go through a mass extinction of life, and still wait a million or so years for it to “cook”.

Of course, eventually, we hope science will find a way to generate unlimited amounts of power. Eventually, someone will develop warp drive, and the associated matter-antimatter power plant. Shortly after that, we will meet Vulcans for the first time. Yet, in the lore of science fiction, even that  happens well past when we run out of our current fossil fuels. So, until that day, we need to make the best of what we have, and find other ways to power our society. The clock is ticking. Time is running out.

To be sure, I like my technology. And technology takes energy. I am not one who advocates we should do without. I believe that with reasonable conservation, new sources of energy, and a firm, unwavering commitment to putting those sources in place, we can continue to enjoy today’s technology, and whatever tomorrow will bring. Along the way, we will be saving those finite fossil resources to be used in ways that cannot be replaced – such as that ’66 GTO for Sunday drives.

So, Presented here is my roadmap to energy wealth. With 10 points, this is the path I believe we have to set upon to feed our need for energy, allow us to enjoy our technology, show respect for our planet and it’s environment, and provide for our future needs. In the vernacular,  to have our cake, and eat it too.


1 - We need to encourage green building practices and conservation where appropriate and effective.

We are not going to stop driving our cars. We are not going to stop running our Air Conditioners, furnaces, microwaves and lawn & garden equipment. Where we CAN make a difference is in places like making our homes more passively efficient. Installing insulation, plugging air leaks, putting in weather stripping. Building green. We can take advantage, where appropriate and economically sound, of newer appliances and lighting methods. Government can require increasing, but readily achievable, efficiency standards for our gadgets, toys, and tools. We can try to turn our lights off when not in use, without running around in the dark.

2 - We need to start integrating Plug-In Hybrids and Electric vehicles into our transportation system.

Electricity is the most efficient, widely available, and most useable means we have to transport energy. It is also highly amenable to powering our vehicles. With the sole exception of batteries, electric vehicles are mature technology, easily manufactured, and work, drive, and perform virtually the same as current vehicles.

Electricity, from an engineering standpoint, is actually a simpler, more desirable and more flexible drive system than current internal combustion drivetrains. Except for those darn batteries. But, as a couple of manufacturers are already proving, the battery technology is already there to support a large part of our short trip, and commuting driving. The only difference to the owner is plugging it in at night – verses stopping at the gas station.

While we currently generate most of our electricity with fossil fuels, large electrical generating plants are far more efficient at using resources than a conventional internal combustion vehicle. While those plants produce pollutants and greenhouse gasses, it is much easier to control those at a relatively small amount of places, as opposed to a couple hundred million point sources. Electricity can be distributed with relatively little loss, and electric vehicles themselves are quite efficient at making use of the electricity. With all things considered, electric vehicles are still several times more efficient at using our fossil fuels than gasoline powered ones. Electric vehicles also remove the source of emissions away from crowded inner cities, contributing to a cleaner local environment in our cities.

But, more important, most alternative energy sources – wind, solar, hydro, wave & tidal, Biogas fuel cells, produce electricity as their end product. That makes them a natural for integrating into our larger electric grid. As all these distributed sources feed their, maybe small, portion of power to the grid, electric vehicles can use the amalgamated sum of their energy.  Eventually these alternative sources will start displacing our fossil power plants, moving us closer to the goal of total renewable energy, and less fossil fuels. Every time we convert energy to another form, we lose some of it, It is much more efficient to use the energy in the form it is created – electricity.

Of course, many people do not have one car for commuting, and another one for longer trips. Most vehicles have to support many uses, For that reason, Plug-In hybrids are a sound alternative.  With a plug-in, short trip driving is accomplished with electricity from our grid. When there is a need to drive further, old, reliable gasoline is still  there to provide the range. A win for practicality, energy, and the environment.

3 –  We need to encourage the conversion of fleet vehicles and long haul trucks to Compressed Natural Gas (CNG).

There are some places where electric vehicles or plug ins do not make sense right now, either for technical, or economic, reasons. Fleet vehicles – Busses, city trucks, taxi cabs, the list is long. These vehicles have to make many short stops, often with longer distances mixed in. These are conditions that will deplete a battery rapidly. However, these vehicles are normally fueled at centralized locations, where infrastructure can be put in place readily. These vehicles should be encouraged to use CNG – Compressed Natural Gas. Simularly, long haul and inter-city trucks make long trips, and need significant levels of power. This is also well outside the capacity of current battery technology. But, the fueling points for these are also contained to a relatively small number of places that could also easily support CNG refueling infrastructure. The technology for CNG fueled vehicles and trucks currently exists and is readily obtainable.

CNG is also a highly suitable bridge fuel for our other vehicles. Currently CNG is much cheaper than gasoline per Gallon Gasoline Equivalent (GGE), and it creates less pollution and greenhouse gasses than gasoline.  There are many CNG vehicles available already, and many more on the way. Fueling with CNG is also getting easier. There are currently as many CNG fueling stations in the US as there are E89 stations, and more are being put in every week. Unfortunately they are most concentrated in certain areas, but that will change as the market expands. You can also purchase a compressor station for your home, and use your own natural gas supply to refuel. There are currently some subsidies and tax credits in place for purchasing both the vehicle, and the fueling station. The conversion is a simple one for a manufacturer, and dual fuel vehicles are becoming common. CNG tanks do take up room in the vehicle, and their range is normally shorter than a comparable gasoline or diesel one. However, these are things that are easy to live with. Finally, a plug-in hybrid using CNG for it’s internal combustion engine would be the best of both worlds.

We must keep in mind though,  CNG is only a bridge to eventual electric when the battery technology is there or replaced by something else. Our current natural gas supply is getting smaller, and new supplies are more expensive to recover. This, along with increased demand, will certainly drive prices much higher. And, remember, it is still a finite, fossil fuel.

4 - We need to strengthen, expand, and upgrade our electric distribution infrastructure.

Of course, to power all these new electric vehicles, and in order to power our existing homes, buildings and industry, we need to get the electricity from all these generation sources to the end user. We also need to be able to combine the outputs of the many smaller distributed generators. That is the job of our electric grid.

Currently our nation's electric grid is frail, outdated, and in many places, overburdened. It also does not have the control capacity currently to accept large amounts of power from wind farms or other power producers, nor can it presently take advantage of a large amount of distributed generation. We need to expand, enlarge, and update the grid. Larger, more efficient conductors, better, more flexible switch and distribution yards, and many more ways to allow power to be fed into the grid from many more, smaller, sources of electricity. Supply and demand of the electric grid has to be managed in real time. The grid cannot store electricity – yet – we must make exactly as much electricity as we use, no more, no less. So, achieving the goal of distributed generation requires better and more flexible control systems.

This is the purpose behind Smart Grid. Putting in place more flexible and robust control mechanisms to allow this management. At the user end, Smart Metering will allow, not only better monitoring, but the ability to control individual distributed generation at our homes and offices (such as Solar PV), and allow for the accounting and  measuring of the energy produced or consumed. Smart metering will enable the economic benefits of distributed generation.

5 - We need to find ways to incentify large scale wind power projects, and make it easier for them to supply power to our national grid.

Wind power scales up nicely. Large wind turbines are very efficient, and can be sited where many of the objections to them - noise and aesthetics are two - are not as relevant. However they are an expensive initial investment, they require much maintenance, and the electric infrastructure has to be in place to deliver the power they produce. There are also many ecological concerns - bird strikes, and even concerns by Air Traffic Control with radar interference. While wind has the potential to be a formidable source of our electrical needs, we need to aggressively identify and resolve the issues facing it's adoption. This is a place where government, in the arenas of regulation, rights, licensing, and subsidies or tax abatements, can have a significant positive impact.


6 - We need to encourage and promote residential solar Photovoltaic power, and distributed generation.

Solar Photvoltaics, unlike wind, scale DOWN very well. A large solar installation is very expensive, uses a lot of land, and is complex. A small installation however, which can supply a significant percentage of a homes electrical needs is simple, reliable, and becoming much more cost effective every day. This kind of distributed generation removes much of the burden from our electrical grid, brings our homes closer to energy self-sufficiency, and is the ultimate in environmentally friendly. Again, government, via subsidies to homeowners, and regulatory oversight, can do much to get this technology in place.


7 - We need to rebuild our Railroads, and encourage more use.

Railroads are the second most energy efficient way we have to move goods - after Ships. They are four times more efficient than trucks for moving large amounts of material long distances. Although I truly do lament the effect it would have on our trucking industry, we need to move more of our long distance shipping to this old, stable, and efficient method.

8 –  Biogas

While Biogas is not sufficient in quantity to power our vehicles, it is already proven as an effective source for small, distributed, electrical generation. It also can serve well in third world countries for cooking, refrigeration, and some space heating. In combination with Large Scale Wind, and small-scale Solar PV, biogas from landfills or agricultural and livestock waste, can make a significant contribution to our overall supply of electricity.

9 – Small-scale electric generation – distributed generation.

From small hydro, to tidal currents, there are many ways to generate electricity from natural phenomena. By promoting, and encouraging these small-scale systems, and not trying to make them the be all – end all of power, they can also make a significant contribution to our overall electricity supply. We need to encourage small scale innovation, and make it easier and economically possible for small companies, with a good idea, to put their creations in place, and connect them to our infrastructure. With appropriate modernization, our electric grid is an enormous resource. It has the potential of allowing the interconnection of a multitude of small scale power producers, all contributing their share to the national need for energy. Not only will this reduce our need for fossil fuel generation, but it can be the incubator for the creation, and proliferation of profitable and innovative small business. Combining residential and small commercial solar photo-voltaics, with the outputs of thousands of producers like “Bob’s tidal power”, we can switch this country from centralized fossil fuels to decentralized, reliable, and environmentally sound distributed power sources.



10 – Industry and manufacturing.

While there is much basic research into alternative energy going on in this country, the sad fact is much of the applied research, design, and especially manufacturing of alternative power systems is happening in other parts of the world. We need to find ways to bring both the technology, and the industry back home. This is again a place where local, state and federal government can rightfully encourage progress. By encouraging technology transfer from basic research to private industry. By providing financial backing to those industries to support and develop innovation. By economic and political incentives to re-purpose idled production assets, factories, and facilities into the production of the physical hardware we need to accomplish our energy goals. By making it easier and less expensive for companies to acquire and retain skilled workers, engineers and managers. By a vigorous, directed, and unrelenting push to rehabilitate our basic educational systems. By a purposeful, and high profile campaign to enhance science, technology, engineering and math education and interest in our schools. By encouraging Americans to once again embrace science and technology.



Finally, incorporating all ten of these steps, I would propose a project, and an investment, by this country and it’s citizens. A project on the scale of, and in the spirit of, Apollo and the moon landing in the sixties. We need to set forth an agenda, a time-line, and a goal. We need not have all the answers, we need not specify how we will accomplish it, but only what it is we will accomplish. We need to make it not only a national priority, but a national agenda, and a national passion. We have spent many billions propping up our financial systems. Whether that was necessary is not the subject of this dialog. However, moving forward, we need to dedicate the same level of resources, financially, politically, and spiritually, to achieving not only energy independence, but responsible, renewable, abundant energy. We CAN do it. We have the technology - now. We have the need – now. We only need the intestinal fortitude from our politicians, our government, our leaders, our industry, and our citizens, to make the commitment, and follow through.

So, there it is. My Ten steps to a better, cleaner, more vibrant and sustainable energy future. I am available for consulting work if the fee is right. Drop me a line!

No, really, I want your thoughts. Please comment!

Starship Power Systems

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Not everyone has a chance to visit a Federation Starship. So I thought I would give a brief description of how they generate and use energy. Naturally, this is just a brief description. If you are interested in learning more detail, you would do well to peruse the many official Federation Documents available on the web,

The energy that powers a typical starship is created by a standard matter-antimatter reaction. The reactants in this case are deuterium and anti-deuterium, used due to their ability to supply the large amounts of power needed by warp drive,  energy weapons, and the various structural fields. The reaction takes place in a reactor vessel (the warp core) where the fusion reaction is contained by powerful magnetic containment fields. The deuterium is contained in a large tank inside the vessel.. Bussard collectors mounted on the warp coil nacelles are used to collect a small amount of replenishment deuterium as well as hydrogen from space via the ram effect.  Although important for other ships functions (see maneuvering thrusters) This is not sufficient to completely replace the deuterium that is consumed. For this reason a Federation starship has to be refueled approximately once every three to five years, depending on class.

The Anti-deuterium is an isotope of hydrogen which contains one antiproton and one antineutron in its nucleus, and one positron orbiting the nucleus. It is manufactured onboard in a catalytic fuel reactor from hydrogen, and then stored in special anti-matter pods. These pods can be ejected from the ship in times of emergency. The pods have a magnetic containment system to contain the anti-deuterium. Normally this system is powered from the primary EPS, but each pod has a small self contained power generator that can also maintain the containment, even if the pod is ejected, or if all other ships power fails.

An important element of the matter-antimatter reactor are the di-lithium crystals used to control and moderate the reaction. Without these the reaction would rapidly get out of control. Di-lithium is used for it’s ability to absorb the anti-deuterium protons while withstanding the immense heat of the plasma. They operate in much the same way that graphite is used to moderate the nuclear fission reactors we all learned about in grade school. As an aside, anyone who has assembled a fission reactor knows very well the necessity of these moderating elements. Some have found out the hard way – to the great dismay of their parents, and  the insurance company.

The resulting plasma from the matter-antimatter reaction is distributed to various other parts of the ship through plasma conduits. These conduits also use magnetic containment to direct the plasma flow. The largest of these, known as Jeffries tubes, are used to transfer the large amount of plasma needed, and it’s concurrent energy, into the warp nacelles. From those, the plasma is metered into the actual warp coils via the Gravimetric Field Displacement Manifolds. These serve as the controlling element to control the size and shape of the warp field that is generated. I will not get into the mechanics of the warp drive itself. For most readers, the basics of warp propulsion have already been well covered in their secondary schooling.

Smaller, but still fairly large, plasma conduits supply power to the transporter, the primary structural integrity field generators, and to the weapons bays for use by the phasor emitters. Two completely separate plasma conduits (one for backup) are used to power the primary deflector field emitter dish at the front of the ship. As you are well aware, this is a critical component when travelling at warp speeds, so the backup conduit is not an option. A further large plasma conduit system is used to supply energy to the gravimetric field generators. These coils are used to supply artificial gravity throughout the vessel, and are strategically located near the lower surfaces (as defined by the primary 3-dimensional co-ordinates)  of all the primary hull structures.

Smaller plasma conduits, known as EPS (Electro-Plasma System) conduits, run throughout the ship distributing energy to where it is needed for things such as lighting and electronics power, replicators, waste management, water, and environmental systems These conduits are arranged in a tree fashion, called the power transfer grid, and are controlled and monitored at various points by Jamieson power junctions.

A note: There is some controversy over application of the EPS terminology. In older starships the entire power conduit system was known as the EPS system. These older vessels used a relatively few amount of plasma conduits, and powered the major systems (except the warp drive) via standard electrical distribution and EPS power taps.

However, this discussion centers on newer designs where there are separate conduits for the major elements as noted above, and for general ships power, which is now generally called  the EPS. Modern starships distribute plasma to many more points than older models there.

At points where normal electrical power is necessary, EPS Power taps, similar to the seebeck devices used in your own home, are installed. These are used to convert the heat from the plasma into an electric current. These devices are mounted in the sides of the plasma conduits to supply electrical power.

It is interesting to note that the Impulse engines are separate, and powered  by their own Nuclear Fusion reactors. These reactors supply the impulse drive directly. As you know, the impulse engines are conventional magnetoplasmadynamic engines which provide thrust by using electromagnetic coils to emit bursts of accelerated matter. The impulse reactors can also supply enough power, via the EPS system and power transfer grid, to the rest of the ship, to maintain essential ships functions, life support, and some weapons capability. The impulse reactor systems also supply primary power to the inertial dampers that are necessary to counter the effects of time dilation caused by use of the impulse drive at higher, but sub warp,  velocities. The inertial dampers on older vessels were powered from the primary EPS. This setup was changed after a notable incident with the Enterprise “B” model, where the inertial dampers failed at a critical trans-warp period. This situation nearly caused the loss of the entire ship and crew. The failure was later traced to inadequate output from the warp core.

Ship’s maneuvering Thrusters, on the other hand are  high-efficiency reactant propellant types of thruster using on-board propellant created from some of the hydrogen that the Bussard collectors provide.

It should be noted that there are various other small fusion reactors throughout the ship. These reactors are of the Tokamak variety, and are essentially self-maintaining. Their primary purpose is to provide an uninterrupted flow of power to critical systems such as the EPS containment fields, and of course, the warp core. This entire system, the CIAS (Containment integrity assurance system) is completely self managing, and rarely mentioned in basic texts. It was instituted early in the starship program after the tragic loss of the USS Pernicious due to an EPS Conduit breach.

Before ending this discussion, it would be prudent to mention the ship’s computer systems. Although the interfaces to the computer core, as well as the core itself, are optical in nature, a large amount of energy is necessary to power this highly critical component. To that end, via the EPS, and a separate, redundant, DIPS (Data integrity power system), the ships computer core can draw on any number of power sources to maintain it’s functioning. This power flow is essentially uninterruptable, and completely automatic in function.

US Electrical Supply & demand

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Where does electricity come from ?

Electricity is not a source of energy. It is a transport mechanism, and way to move energy from one point to another. Along the way, the energy gets converted many times. Each time, there is a little energy lost. Electricity is generated by an energy source - Coal, wind, water power, nuclear reactions, etc. The energy derived from these sources is then converted to electricity by a power plant, or generation source. This may seem to be a trivial distinction, but it is very important in understanding how we use energy.

Let's take one example. A power generation station burns coal. That coal creates heat, which heats water into steam. The steam then turns a turbine which converts the heat into mechanical energy to turn a generator which converts that mechanical motion into electricity. The electricity travels across the distribution grid to your home, through the wires inside your home to your washing machine. Inside the washing machine a motor converts that electricity back into mechanical motion to wash your clothes.

It is also an important note that electricity cannot be stored by our national electric grid. Literally every time you turn that washing machine on, a generating plant - somewhere - starts making a little more electricity to make it run. An amazing thought - but one that is important to many of our discussions of alternative energy. It is the function of operations centers and their computer systems throughout the country to balance this supply and demand.

Not being able to store that electricity makes a significant impact on how we generate it. First impact is, we have just enough generation to meet the demand. It does not make economic sense to build a power plant to create electricity that is not needed! So, if we, as a country, start using a lot more electricity, someone will have to invest in building a power plant to meet that new need. For example, a widespread acceptance of plug-in hybrid cars would use more electricity. Someone will have to build more power plants to meet that need.

A large power plant is only efficient (makes a profit) if it is running at near it's capacity. This is true of Coal and nuclear plants, and somewhat true of hydroelectric (since they still have to be maintained). This gives rise to power companies supplying two kinds of generation capacity. Baseload is the average amount of electricity this country uses 24/7. This is the demand that large scale plants are built to supply. However, there comes a time most every day when our demand exceeds that. It is most often in the late afternoon, early evening. This additional demand is called Peak Load. Power companies maintain many, many, small power generators called "peaking plants". These plants can be quickly brought "on-line" to supply that excess energy. Most of these Peaking plants are run by gas turbines, similar to a jet engine. They supply around 1 - 3 megawatts of power each. Most of these turbines are powered by natural gas. The majority of the natural gas that is used for electricity generation in this country is used to run these "peaking plants".

Since we cannot store the electricity, control is very important. Power companies have to be able to not only increase the supply as demand goes up, but reduce that supply as demand goes down. They do this in real time. As the washing machine example above shows, it is an amazing process. The need for this control has a large impact on our ability to incorporate variable electricity sources such as wind power. We cannot just hook up large electrical supplies to our national grid. They must be controllable. Smart Grid technology is one way the power companies hope to allow better control, and the addition of many small power supplies to our grid - Distributed generation.

But, I digress. Let us first look at what supplies this country with electricity, and then where all that electricity goes.

This country has a total grid connected generation capacity of slightly more than 1,000,000 Megawatts (1,000 gigawatts). Additionally, many companies and factories generate their own power. To that end there are an additional 8,000 megawatts of privately owned generators that are not connected to the grid, and 12,000 megawatts of privately owned generators that are connected to the grid.

Here is a report on installed generation capacity:

http://www.eia.doe.gov/cneaf/electricity/epa/epat2p2.html

A note about the above. The generation capacity cited is from the EIA, and called "nameplate capacity". That is the maximum amount the particular generator CAN produce. However, breakdowns, planned maintenance and repairs, and other factors (such as a lack of fuel) reduce the amount of energy that is actually available. This is called Capacity Factor. Various technologies have different capacity factors. In 2008, For Coal that factor is 72%. For nuclear it is 91%. Combined cycle gas plants achieved 42%, while single cycle stood at 10%. All renewables together were at 37%. By my figures, the average across all types of generation plants is currently about 55%. This makes our total actual generation capacity at about 550,000 megawatts, or 4,818,000,000 megawatt-hours per year.

• In the US nearly half of our electricity is generated by Coal fired plants. (49%)
• Nuclear power plants supply about twenty percent of our electricity.
• Natural gas accounts for 21% of our generation - Much of this as a fuel for Peaking Plants.
• Hydroelectric plants comprise six percent of our capacity.
• Renewable energy sources - besides Hydroelectric - comprise 2.5 percent of our capacity.
• Contrary to some beliefs, very little petroleum is used for generating electricity - about 1.9%.
• Much of that petroleum is used in places where Diesel Generator plants are the only reasonable source of power.

In 2008, this country's electric plants generated a total of 4,110,259,000 Megawatt-hours of electricity. And, we used every last watt of it. This represented 86% of our total electrical generation capacity based on my calculation of average capacity factor. Another way of looking at it is we have a 14% safety margin.

Well, where did it all go?

First, some perspective. (EIA Facts and figures: http://www.eia.doe.gov/cneaf/electricity/esr/table5.html)

• There are 123,949,916 residential electricity users in the US. The average residential consumer uses 949 kilowatthours (KWh) of electricity a month. (Your mileage may vary). That electricity costs an average of 10.65 cents per KWh.
• There are 17,377,219 commercial customers who each use an average of 6,408 KWh per month at an average 9.65 cents per KWh.
• Finally, there are 793,767 industrial customers in the US. They each use an average of 107,907 KWh a month at an average cost of 6.39 cents per KWh.

I have decided to just list a few common users of electricity, and what percentage they use. Some of thes figures are from 2008, some from 2007. In no particular order:

• About 215,000,000 megawatt-hours (MWh) of electricity were used for lighting by the residential sector. This was equal to 5% of total U.S. electricity consumption.
• 311,000,000 megawatt-hours were consumed for lighting of commercial buildings. That is 7.5% of the total.
• Residential customers bought 1,379,307 megawatt-hours of electricity - 33%
• Commercial customers bought 1,352,453 megawatt-hours. - another 33%
• Industrial users bought 982,150 megawatt-hours - 23%
• Transportation consumed 7,652 megawatt-hours - .1%
• The rest was produced on site, unaccounted for, or otherwise not bought or sold. - 11%

The EIA Electric Power Summary for 2008. - Good reading!

http://www.eia.doe.gov/cneaf/electricity/epa/epa_sum.html

Finally, an Interesting factoid:

Appliances account for 64.7% of electricity consumption in the average American household in 2001. Refrigerators consumed the most electricity (14%), followed by lighting (9%).

Here is a report, a little old, about where electricity goes in your home from the EIA:

http://www.eia.doe.gov/emeu/recs/recs2001/enduse2001/enduse2001.html

About this blog

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Another energy blog. How mundane. Why should you be excited to find THIS ONE?

Energy is a large and fascinating subject. It is important to our way of life, our economy, and our future. I think we have a bright energy future ahead of us, but we need to start DOING things now to make it happen. I do not believe that just "wishing it so" is going to have any impact. In the immortal words of a Steve Martin skit "Forget it, that's not going to happen ".

There is a lot of misinformation, many myths, some sleight of hand, and plenty of political rhetoric surrounding energy. My most important task here will be to "open the curtains". Inform, educate, and maybe even entertain, as I present the facts, dispel those myths, and shed light on the rhetoric. I intend to apply logic, data, science and physics to these discussions.

To be sure, you will get the impression there is a lot of "negativity" on this blog. It is not intentional. I believe in alternative energy, and I enjoy the entire energy picture immensely. However there are myriad problems, roadblocks and snags along the way. Before we can address these issues, we have to understand what they are, what effect they have, and what the options are. I do not intend to pull punches, and I certainly do not intend to look at anything through rose colored glasses.

I will, however, continue to use way too many metaphors, quotes, and figures of speech. Yes, I am like that in real life also. It drives my wife crazy. I also write, talk, and illustrate, in groups of three. I do not know why, how, or for what reason, I just do…

So, First of all, the "nots".

• I am not going to just post a link to every little scrap of news about energy that is out there.
• I am not going to mindlessly accept, and dutifully write about, just any information I find.
• I am not going to follow the herd, toe the political line, or ride the "spin" train.

And, here is what I intend to accomplish.

• I will post, talk, dissect, and opine about, significant news in the world of energy.
• I intend to educate about energy, not simply throw things out there.
• I will apply my knowledge of science, physics and technology to dissecting and analyzing energy information where appropriate.
• I hope to consistantly add basic articles explaining energy and technology.
• I promise I will supply plenty of facts, figures, and quotable statistics.
• I will cite references and supply links to support what I say.
• I will not be hesitant to supply MY opinion, but I will strive to support it with facts.
• I will welcome comments, discussion, and dissension. That dialog is what's important!.

I will try to keep order to this blog. There is a Table of contents page. I will keep it updated the best I can, but it is a manually generated page. It is possible that the one or two LATEST entries in this blog have not made it to the Table Of Contents.

If you are looking for something specific, I will keep the postings categorized, hopefully well. But, I just KNOW that is going to get out of hand. Hopefully I will come up with a better way.

I have also added a Glossary Page to define terms, and a Reference page with some useful facts and figures. And, do not forget my store, where you can purchase Books & Videos about energy and science, as well as many other things.

I just started this blog the end of January 2010. I am still trying to fit it into my schedule. I already have much planned to write about. Some of it still involves significant research. I hope as time passes I will be able to afford more time for it. My goal is to have at least one or more interesting posts added a day. I am far from that yet, but... I will get there!

This blog is in addition to my MCC Workshop Electronics hobbyist site - A website I have also neglected as of late, but that I have hopes of pursuing once again when I have the resources. It IS a process :-). If you enjoy electronics and science, or if you are setting up a workshop, enjoy vintage equipment, or vintage (retro) computers, drop by there for a visit!

So, bookmark this blog, come back often, set up a feed, and/or follow me on twitter. (http://twitter.com/Altenergyblog ). I promise you are in for a fun, informative, and useful ride. And, please do not hesitate to add comments, discuss things, or disagree with what I say. I welcome debate, and I am happy to discuss things. This blog also has a Facebook group at: Understanding Energy - The Energy Blog You are of course welcome to join it!

Please read the "About the author" page to learn more about me and my interests and credentials.

You can also visit my personal hobby website at http://mccworkshop.com

Hydraulic Fracturing of Natural Gas wells and The Marcellus Shale (Paper)

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This link is to a very good, and informative paper on Hydraulic Fracturing of Natural Gas Wells. It concentrates on the Marcellus Shale region of the Northeast US, but, it covers many general topics about shale gas (including a map of deposits in the US).

http://www.wvgs.wvnet.edu/www/datastat/GWPC_092008_Marcellus_Frac_Arthur_et_al.pdf

The Marcellus shale region which stretches from the Middle of NY State, through much of West Virginia and Pennsylvania, and on into the middle of Ohio is one of the largest natural gas reservoirs in the US. Covering an area of about 95,000 square miles, it is estimated to contain 225 to 500 Trillion cubic feet of natural gas. Getting that gas OUT of shale, however, involves some what are called unconventional methods. Horizontal drilling being one, and hydraulic fracturing of the rock formation (fracking) being the most controversial. 

Hydraulic fracturing involves pumping large amounts of water under high pressure into the wells. This causes the rock to fracture, and allows the gas to escape up the well. Of course, it is not just water, that would be too easy. Mixed with the water are various chemicals and additives designed to make the process work better.  Also included are "propping agents" designed to keep the fractures open. Many of the concerns about this process revolve around these additives, and their potential to contaminate our drinking water. This paper describes some of those additives.  There is currently no requirement for drilling companies to disclose what chemicals they are using (under the guise of being "proprietary"). Fracking has become a common way to improve recovery (or allow recovery) from wells.

The potential is certainly there, and in a widespread area. The studies indicate a need for up to 16 wells for every square mile (640 acres) of the development. Each of these wells will have to be fraced individually. Each well could use from 500,000 to 1,500,000 gallons of fracturing fluid. And it may have to be done on an ongoing basis. 

Much of the area in question receives 40 inches of rain a year.  This amounts to 731,000,000 gallons of water falling on each square mile. (http://mo.water.usgs.gov/outreach/rain/index.htm). 16 wells could contribute at least 24,000,000 gallons of fracturing fluid to the groundwater. This is 3% of total rainfall. A lot? No worries? Will it escape to the groundwater? Therein lies the debate.

Read the paper. For a view from another perspective, read these :-)

http://www.earthworksaction.org/hydfracking.cfm

http://www.earthworksaction.org/FracingDetails.cfm

Finally, here is Natural Gas dot org's article on wells.

http://www.naturalgas.org/naturalgas/well_completion.asp

Time will tell.

More recent articles about fracking: While I have not made up my mind one way or the other, the only information I can find on this process is either about the process itself, or negative.

http://www.chem.info/News/2009/10/Chesapeake-Energy-Succumbs-To--Fracking--Pressure/

http://industry.bnet.com/energy/10002189/full-disclosure-schlumberger-hydraulic-fracking-and-the-public-access-debate/

http://www.forbes.com/2009/09/28/cabot-hydraulic-fracturing-business-energy-fracking.html 

http://www.hcn.org/issues/41.20/frack-2-scene-1 

http://www.ombwatch.org/node/10353

http://www.propublica.org/feature/is-the-marcellus-shale-too-hot-to-handle-1109

Incandescent Light Bulbs - new lease on life?

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With the passing of the Energy Independence and Security Act of 2007, many thought that incandescent light bulbs were going to disappear, because they could not meet the new efficiency standards. While it is true that many styles of lamps have already gone away, this article I came across appears to give the incandescent lamp some hope for the future.

http://www.nytimes.com/2009/07/06/business/energy-environment/06bulbs.html

See, manufacturers can often make more efficient products if they set their minds to it. Unfortunately economics says they continue to produce what they always have, and what they have an investment in. That is, until something happens to make their old standby products obsolete.

Make no mistake. If you are a manufacturer, and you have a huge investment in factories to produce a product, changing those factories to manufacture a new product can be expensive, time consuming, and a bit daunting. We cannot blame a business for wanting to stay viable, and make a profit on their investments. This is one area where reasonable, and responsible, legislation is not only proper, but can force change in a positive direction.

Wiki article on Incandescent light bulbs: http://en.wikipedia.org/wiki/Incandescent_light_bulb

This is a link to the ENTIRE Energy Independence and Security Act of 2007. Good luck trying to read it:

 http://frwebgate.access.gpo.gov/cgi-bin/getdoc.cgi?dbname=110_cong_bills&docid=f:h6enr.txt.pdf

Since the act is, as usual, highly indecipherable, a summary of it's provisions is handy.

And, here it is: http://energy.senate.gov/public/_files/RL342941.pdf

The Energy content of some fuels

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ENERGY CONTENT OF SOME FUELS

• 1 Gallon of Gasoline contains 124,000 BTUs
• 1 Gallon of E85 Ethanol contains 84,000 BTUs (72% of gasoline)
• 1 Gallon of Fuel Oil (Heating) contains 140,000 BTUs
• 1 Gallon of LNG contains 75,000 BTUs
• 1 Ton of coal contains 20,000,000 BTUs
• 100 Cubic Feet of Natural Gas (Therm) contains 102,000 BTUs
• 100 Cubic Feet of Hydrogen contains 32,500 BTUs
• 100 Cubic Feet of Propane contains 250,000 BTUs
• 1 Cord of Hardwood Contains 24,000,000 BTUs
• 1 Cord of Softwood Contains 15,000,000 BTUs
• 1 Cubic foot of Hydrogen at atmospheric pressure = 319 BTU
• 1 Square foor of Sunshine in space contains 428 BTU/Hr or 127 Watts/Hr
• 1 Square foot of Sunshine on earth (US average) contains 298 BTU/Hr

                 ---- A couple of energy Equivalents ----
• 1 Gallon of gasoline equals 126.67 cu ft of Natural Gas (Methane)
• 1 Gallon of Gasoline equals 33.7 KWh of electricity.
• 1.012 kg (2.2lb) of Hydrogen equals 1 gallon of gasoline.
• 1kg of hydrogen compressed to 2200 PSI takes 2.8 Cu Ft of volume.

ENERGY TRIVIA

• A Boeing 747-400 burns aproximately 5 Gal of fuel per mile
• An F-14 Tomcat at full throttle burns 80 Gal of fuel per Minute
• A top Fuel Dragster gets the equivalent of 1/18 MPG (18Gal/Mile)
• The fuel pump on that same Top Fuel car pumps 65 GPM
• The average US household uses 92 Million BTUS of Energy per Year (2001)
• 48% of this countrys electricity is produced by coal. 20% is Nuclear
• 18% of electric production is from natural gas, and 11% is Hydroelectric
• 7% of our Total energy comes from renewable resources -
• 40% of ALL the energy we use comes from petroleum
• Energy required for 1 Galaxy Class Warp drive: 4,857 Quadrillion BTUs/Minute

 

ABOUT THE BTU

A British Thermal Unit (BTU) is the amount of heat energy needed to raise the temperature of one pound of water by one degree F. This is the standard measurement used to state the amount of energy that a fuel has as well as the amount of output of any heat generating device. In the context of heating devices the output is normally express in BTUs 'per hour' (BTU/h).  The BTU has largely been replaced by the Joule in scientific circles. It is still widely used however when comparing fuels, and in various industries.

A BTU is a fixed amount, or quantity, of energy. BTUs 'per hour' (BTU/h) is a measure of the amount of work done.

• 1 BTU = 1055 Joules
• 1 BTU = 252 calories
• 1 BTU = Amount in 1 Wood Match
• 1 KWH = 3414 BTUs
• 1 KW = 56.9 BTU/Minute
• 1 Watt = 3.414 BTU/H