by Jesse Jenkins
Bloom Energy at the eBay headquaters. Photo courtesy BloomEnergy via Flickr
Cross-posted from WattHead.
With all the hype today around the release of the “breakthrough” Bloom Energy fuel cell (which has become known as the “Bloom box” and is referred to by Bloom as an “Energy Server”), it’s good to find a couple of posts looking at some real details:
Todd Woody, writing for the NYTimes GreenInc blog, has some details on the design of the Bloom Box solid oxide fuel cells from his look inside the Bloom Energy facilities this week. And Lux Research has this post looking at the economics of the Bloom Box, which is a good read.
It
appears that the unsubsidized price of the Bloom Box is about
$7-8,000/kW so their 100 kW units cost $700,000-800,000 without
subsidy. As a fuel cell, it also needs fuel to run, in this case
natural gas or another source of methane (such as landfill gas or
biogas from anaerobic digesters).
After federal subsidies for
fuel cells (they can claim the same 30 percent investment tax credit that
solar gets) and a $2,500 California rebate, and assuming $7/mmBTU price
for natural gas, a 100 kW Bloom Box unit generates electricity at 8-10
cents/kWh. That compares favorable to commercial electricity rates in
many parts of the country, (average about 11 cents/kWh across U.S. with
higher rates in several states, including California, New York, and
Hawaii) so there could be good market for the Bloom Box in distributed
generation applications in a variety of places, assuming federal/state
subsidies holds out.
Unsubsidized cost would be 13-14 cents/kWh,
with about 9 cents/kWh from the capital costs of the Bloom box and 5
cents/kWh from natural gas costs, according to Luz Research. If natural
gas prices rise or fall 50 percent (gas prices are often volatile), overall
price would fluctuate from 11.5-12.5 cents/kWh to 20.5-21.5 cents/kWh.
That unsubsidized price is still too high to compete in most markets
with retail electricity without subsidy. However, this is the first
generation, and if Bloom can bring prices down (and/or natural gas
prices are stable/low), there could be a significant market for this
fuel cell.
As far as climate benefits, supposedly it generates electricity at 50-55 percent conversion efficiency. CO2 emissions when running on natural gas would be just under 0.8 pounds/kWh,
which compares favorably to electricity from central station coal-fired
plants (2 lbs/kWh) or natural gas plants (roughly 1.3 lbs/kWh) and the
national average for on-grid electricity (around 1.3-1.5 lbs/kWh).
Clearly, though the Bloom Box is still not a zero emissions tech and
would only cut emissions by roughly 50 percent relative to the national
average, unless it runs on landfill gas or biogas or hydrogen from
electrolysis fueled by zero-carbon electricity (which would be much
more expensive as you have to add cost of electrolysis unit, higher
cost electricity, and about 30 percent conversion losses in electrolysis).
It
is also worth noting that the average emissions rate of grid
electricity in some states is less than the Bloom Box’s 0.8 lbs/kWh.
According to EPA’s eGrid database, that list of states includes
Vermont, Idaho, Washington, Oregon, California and New Jersey. However,
EPA does not account for imported electricity across state borders,
which tends to increase the emissions rates of most of these states.
California, for example, has an emissions rate of about 0.65 lbs/KWh
according to eGrid—which is notably less than the Bloom Box’s
emissions rate running on natural gas—but more like 1.0 lbs/KWh when
imports of mostly-coal-fired electricity from out of state is factored
in (author’s calculations). When imports are factored in, this author
calculates that average emissions rates for on-grid electricity in
Vermont, Washington, and Oregon still fall below that of the Bloom fuel
cell (but emissions rates vary within each state from utility to
utility as well).
Solid oxide fuel cells have notoriously faced challenges with durability, since they operate
at very high temperatures, which the Bloom box will also have to
overcome to prove profitable. Todd Woddy writes:
In seven months of [pilot test] operations, Bloom has replaced a few fuel-cell wafers, but the machines have otherwise operated without a problem, Ms. Skoczlas Cole [of Ebay] said.
Bloom executives said the company spent years developing a proprietary seal made from low-cost materials to prevent cracks and leaks. They estimate that the Bloom boxes will have a 10-year lifespan and that the company will have to swap out the fuel-cell stacks twice during that time.
Mike Brown, an executive with UTC Power, a leading fuel-cell maker, said the fuel cells need to last at least four or five years for the technology to be competitive.
The advantage of solid oxide fuel cells running so hot is that all that waste heat can potentially be put to good use. When co-generating heat and electricity, solid oxide fuel cells can reach combined efficiencies upwards of 85 percent, which is excellent, but no word yet whether or not the Bloom fuel cell will co-generate heat. At this point, it appears that it does not (particularly given it’s use to power data centers and the like, which can’t put the heat to very good use; cooling is more of an issue for data centers!). That’s a shame, but perhaps another model of the
product at some point in the future will be suited to co-generation
applications (e.g. to provide process heat to industrial facilities or
neighborhood district heating schemes). [Update: commenter Amazingdrx at Grist reminds me that waste heat can indeed be used to provide cooling using the common absorption refrigeration technique (which I should have recalled, since the entire campus at my alma
mater, the University of Oregon – Go Ducks! – was cooled using
absorption chillers run by our natural gas plant). So the waste heat from these fuel cell stacks should be used to cool the data centers they also power, increasing the efficiency and economics of the system…]
I also hear that it may require zirconium oxide as a membrane (can anyone confirm that?) and zirconium doesn’t grow on
trees, nor is it processed quickly, which may hamper production volumes.
So
is the Bloom Box the solution to all the world’s energy problems? Of
course not. But could it finally move fuel cells for stationary power
generation a big step forward? It looks like the chances are good. Only
time, and the tests of the market, will tell …
It’s worth
noting though that with the idea initially funded through NASA’s Mars
program and initial product launch only enabled by public deployment
incentives, the Bloom Energy fuel cell is another good example of how public investments in technology R&D and deployment can catalyze significant private sector investment, innovation and
entrepreneurship to drive forward a new technology with potential for
widespread application as costs come down.
Related Links:
Bloom: Thinking inside the box
What the heck is a Bloom Box and will it solve the world’s energy problems?
Ask Umbra’s pearls of wisdom on nuclear energy
