GE Delivers Coal-Fueled, Solid Oxide Fuel Cell (SOFC) Prototype
by John Laumer, Philadelphia on 10.25.06
Technology Review captures it nicely: "GE's advance allows for a solid-oxide fuel cell to use coal-based fuels at costs approaching that of conventional power plants". This is a 6 kW prototype fuel cell, delivered for their partner, the US Department of Energy, to test. Positives include a nice breakthrough in fuel efficiency (49%, vs 35% for a conventional coal-fired electricity generating plant); a dramatic lowering of manufacturing costs compared to previous SOFCs (down to about $800/kW); and, the ability to utilize a hydrogen by-gas stream from a "clean coal" syngas plant. Drawbacks: the feedstock processing step is capital intensive, and has a large environmental footprint (as does all coal); any sulfur in the coal-based fuel would eventually "poison" the SOFC's electrolyte, requiring near-perfect desulferization efficiencies at the syngas plant. Bright side analysis: assuming that the syngas plant effectively sequesters sulfur as a co-product or safe, solid waste stream, the GE SOFC design offers a strong incentive for operators to keep per kW sulfur emissions associated with the SOFC to zero. Dark-side analysis: if the Federal Government offers slack air and water discharge permit conditions to coal syngas plants, the precedent will likely never be overcome, and sulfer acid gas emissions per kW will be not much better than existing coal-fired generators. Note: chemical markets need only so much elemental sulfur or sulfuric acid and any excess if these will eventually have to be disposed of. Typically, sulfuric acid would be neutralized with limestone to create gypsum, or calcium sulfate. If a syngas plant's aqueous acid stream contained heavy metals from coal washing and off-gas scrubbing, the gypsum so-created may not be suitable for soil amendment purposes and, instead, may have to be managed as hazardous waste. Unless, of course, yet another permit exemption were offered. In other words, we can't call the prototype SOFC a "green" technology until we see what the syngas plant footprint is. Photo credit: GE, via Technology Review.
There's also probably an efficiency benefit because these would most likely be used where the power is needed (saving on transport).
But still, I can't say I'm very excited about this. There's so much we could do before having to use coal in such a way. Maybe after big investments in wave power, wind power, solar (nano solar, eventually).. Maybe even those thorium nukes we heard about recently.
I am actually very excited by this, despite the big ugliness of coal.
The reason is, as the previous poster suggested, the potential for onsite power generation. Onsite generation does improve electrical efficiency somewhat, by eliminating transmission losses.
But the real benefit is the potential for co-generation. These fuel cells operate at high temperature and produce significant waste heat. 50% electrical efficiency is REALLY good, but the other 50% of that energy is given up as heat. In a central utility situation, that heat is generally dumped, and lost. With distributed cogeneration, that heat can be captured for use on site, for hot water, space heating, or refridgeration (with adsorbtion chillers). This offsets fuel that would otherwise be burned for the purpose, and gives you a total system efficiency of 80-85%, which is almost THREE TIMES better than average grid power. That's a big deal, even if the damn thing does burn coal.
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Agree completely. GE is otherwise vested in coal fired electricity equipment and USDOE currently is, shall we say, 'coal focused'. So, this pairing seemingly is a natural framework of the partnership. On the otherhand, biomass makes syngas just as well as coal, maybe more cost effectively; and biomas bypasses the coal-associated mountain top removals and the mercury, sulfur, flouride, chloride, arsenic, and lead emissions issues entirely. Go go for it GE.
Forgive the late submission. I just stumbled upon this article.
Everyone is missing the HUGE potential of this system. The potential is not for coal. That is better used in centralized power plants. The potential is in converting wood waste or other waste to electricity on site. Many manufacturing plants and processing plants make a huge amount of waste. Currently, many of these plants pay to dispose of this waste. This technology could be easily converted to gasifying wood waste (almost zero sulfur) and converting it to electricity.
I know this because I am a Research Manager who is developing a system for this nich market. The one HUGE problem is the SOFC. Currently, that technology just is not developed enough to take advantage of the gasifier system we have developed. This technology would overcome that barrier.