Prometheus 6

Of all biofuels, biogas delivers most energy per hectare of crops. It is also the least carbon intensive production path, with some biogas pathways actually delivering carbon negative bioenergy (earlier post). In Germany, some project the potential for biogas to be so high that it might replace all natural gas imports from Russia (see here).

Biogas powered fuel cell wins award, attracts attention from Sweden

Acumentrics Corporation, a leading developer of solid oxide fuel cells has won the 2007 New England Innovation Award from SBANE, the Smaller Business Alliance of New England. The company was one of 7 winners chosen from a pool of 171 applicants.

Acumentrics manufactures 5000-watt solid oxide fuel cell systems (SOFC) for power applications. It is also developing combined-heat-and-power units for the home market. Originally the company made power conditioners and backup for the military market. They acquired the fuel cell technology in 2000. Since then, they have increased the output of a single tube from 1 watt to 60 watts. Today they have over 30 fielded units.

One of their key innovations was making ceramic fuel cell technology shatter resistant. It is shatter resistant because of its shape - it is a tube, not a thin sheet as most other fuel cell manufacturers have used - with a special composition of layers that prevents them from flaking off (diagram, click to enlarge). Solid oxide fuel cells must handle temperature swings from 20 to 800ºC. Many other solid oxide fuel cells crack when they are cycled on and off, because of thermal shock.

Carbon neutral biogas
Another highly important feature of the SOFC's is that they do not require hydrogen or the hydrogen economy - which is mired in controversy because it requires huge investments in production, distribution and storage technologies. Acumentrics' fuel cells instead run on biogas, natural gas, propane, ethanol, diesel, and biodiesel - because they can disassociate fuels in the tube, via in-situ reformation (diagram, click to enlarge). While their systems can run off hydrogen, too, customers prefer to work with logistic fuels that are more affordable. Acumentrics fuel cells consume half as much fuel as a comparable small-engine generator, per kW. The combination of carbon neutral biofuels with highly efficient fuel cells makes for what is probably the cleanest and most efficient power system currently in existence.

The fact that SOFC's can be fed carbon neutral biogas instead of hydrogen has attracted the attention of the EU, and more in particular of Germany and Sweden, world leaders in biogas production. In Germany, the fuel cell was used with biogas in a world's first, to cool a server farm. The biogas is supplied by Schmack Biogas, global technology leader in the sector (earlier post). Another SOFC project making use of biogas and delivering both heat and power in a highly efficient way was launched late last year by German company MTU CFC in the District of Böblingen in Leonberg (previous post).