Well, the Bloom Box – Now called the Bloom energy server – was formally revealed on Wednesday. Most of the technical details are now on their website. So, naturally, after all my previous commentary, I must comment once more.
It is, indeed a Solid Oxide Fuel Cell (SOFC). It generates 100 Kilowatts of power. According to the specs it requires 661000 BTUs per hour from the natural gas input (apx 700 Cu Ft). That is 193 KWh worth of Natural Gas in, for 100 kWh out for an efficiency of 51.8 percent (Which is, indeed “greater than” 50% as quoted on the web site).
I assume this is the total efficiency of the unit (including inverter), and, as such, it is a modest increase over other Solid Oxide fuel cell efforts I have seen. Good for them.
It weighs Ten Tons! And, my head weighs as much as I bow it to apologize for a mis-statement in an earlier post. I stated that the device would still need a reformer to produce hydrogen for the fuel cell. For most fuel cells this is true. However, because of the high temperatures a SOFC works at, they can apparently do “self reformation” within the cell itself. A small “pre-reformer” is still necessary, but not all the complexity of a complete steam reformer. I was not aware of this, although apparently to the people who actually design these things, you know, scientists, it is common knowledge. Neither do I know how this process works – yet. But, I do apologize for the inaccuracy.
CO2 emissions are 773 pounds per MWh. A typical coal plant, according to the EIA, emits about 2000 pounds per MWh. So this emits about 1/3 the CO2 of a coal power plant. The same source quotes natural gas turbine plant CO2 emissions at 1300 pounds per MWH, so it is about half as much as those, although I am not sure I quite buy their CO2 emissions number. Since the carbon is not used in the process, I would think it would be closer to the natural gas turbine plant. Still, much less than coal, and I’m no chemist.
One problem with a SOFC is the extreme temperatures they operate at.- up to 1800 degrees F. At those temperatures reliability has been a problem with other designs. There is no mention of this on their web site. Bloom is offering a 10 year guarantee on the units. Time will tell how reliable they are.
So far, so good. But, then, there is a matter of cost. Oh, there is always a rub. No where on their web site can I find information on cost, so I went looking elsewhere. According to an article on Forbes (as well as a couple of others I found), the box costs approximately $700,000. ($7,000 per kW) There are reports that Bloom is hoping to get the cost down to about $2,500 per kW in about five years. That would put the cost of the box at $250,000. Now there are government rebates and subsidies. Especially in California, which is where all of the initial units have been installed. You can read the Forbes article below for info on that.
But, let us look at the economics of the Bloom Energy Server. Specifically as relates to a residence, as their stated goal is to use these to replace the electric grid to homes.
My only reference to the cost of natural gas and electricity is my own residential bills. To Produce 100 kWh of electricity, which at my rate of 8 cents per kWh would cost $8.00, the box requires 6.6 CCF (hundred cubic feet) of gas. That gas, at about $0.90 per CCF delivered would cost me $5.94. So for every 100 kWh of electricity, I would save $2.06. - Stay with me- I currently average using about 1400 kWh per month. That means I would save $28.84 every month. Or $346.08 per year getting my power from the Bloom Energy Server rather than staying with the grid. OK, not a lot, but still a savings. So, let’s rip out the grid connection. But wait, there’s more, I have to purchase this thing. And, therein lies a rub or two.
Certainly, I wouldn’t need this big of a unit. However, if I were to replace my electric service with a Bloom Energy server, it would have to supply my entire 200 amp home service. That is 44,000 watts worth. See, while I normally don’t use that much at once, there is the electric stove, water heater, air conditioner, power tools, and they might have to all be on at once. That is why we have the 200 amp service, and since we are replacing the electric grid entirely, we need to replace it’s entire capacity. So, 44 Kilowatts times even his target price of 2,500 per Kilowatt is an $110,000 investment.
I still have to pay for the fuel, so my savings stay the same - $346.08. So, that works out to a Payback (break-even) time of 317 years. Wait, did I do that right, yep. 317 years. For a box guaranteed for 10 years?
That is the rub with completely replacing the electric grid, especially to a home. See, I don’t normally use anywhere near 44,000 watts at once. But, sometimes I do, or at least come close. So, the capacity has to be there for those times. With the electric grid I do not have to purchase ALL that capacity, just what I need at the moment. My capital cost is spread out over all the users. With the Bloom Energy Server (or any other private power plant). I have to make that entire investment up front.
OK, that would be silly. So lets make one more calculation, one closer to reality. Lets stay connected to the grid for those high power times, and we will put in a more reasonably sized Bloom Energy Server to supply my average needs, Like, say, 2500 watts. Now, the good thing is I can sell excess power back to the grid – store it there if you will - so that 2500 watts running constantly should just about eliminate my electric bill. I might even make a little extra. Sell it back. But, I still have to pay for the gas, so my actual savings are still $346.08 per year (Minus whatever the electric company charges me just to stay connected). The box costs $6,250. At $346.00 per year, that payback time is still 18 years. And, what about those days the stove and a/c are running? I may still have to purchase some electricity from the grid. Or, if I get a new Plug In Hybrid, or a hot tub. I will need to purchase the extra power from the grid. I am sure, with subsidies, and proper financing the numbers can work out a bit better, but it is still not a very viable proposition, and we do not know if the box will even last that long, or what maintenance costs are incurred,
Other than the economics, and despite the unwarranted hyperbole, I think Bloom may have a winner here. But are there enough customers? It will not work for a typical home or small business. It may not work for the average factory. It is only going to work, even then with modest savings, in a place with a steady, continuous and predictable electrical load – like an office building, or a data center… Hmmm.
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