Todd Woody at the NY Times has had a couple of stories in the last few days on The Bloom Box, or Bloom Energy Server, a solid-oxide fuel cell designed as an on-site distributed generator. Present costs are still rather pricey - $7 to $8 capital cost per watt (or $7000-$8000/kW - I had this mixed up earlier - see this analysis from Jesse Jenkins for details) plus the cost of natural gas as fuel and any operational and maintenance costs (and they're only claiming a 10-year lifetime). Efficiency is quoted at 50 to 55%. Higher efficiency and lower capital costs would be essential to making it truly useful. Still, I find this a good step forward in the technology. Why?
A few points that distinguish this type of fuel cell from some of the others that have been discussed:
- it is fueled by natural gas, not hydrogen. I.e. the fuel to run these already has a distribution system, and renewable sources (bio-gas) are possible.
- it doesn't require precious metal as catalysts (it runs hot, instead, to get the electro-chemistry going)
- it is stationary - waste heat can be used for local co-generation purposes (and it's at relatively high temperatures)
Right now a simple gas turbine generator would probably be a better choice for local generation (less costly and not much less efficiency), and a combined-cycle gas turbine runs at even higher total efficiency in conversion to electricity. But there is no way to improve the efficiency of those systems, while a fuel cell in principle can get much closer to 100% efficiency. So this sort of fuel cell may be a good choice for further R&D work, if there is real potential for prices to drop further and the efficiencies to improve; it's not very far away from being the first truly competitive large-scale fuel cell technology.
But it's not quite there yet.