http://www.corporate-ir.net/ireye/ir_site.zhtml?ticker=fcel&script=412&item_id=913867
Biogas from brewery waste digestion is being used in direct fuel cells, and the waste heat is used to generate steam for the plant.
Turbines can be added to harvest the waste heat as well, generating extra power. Then the heat from the turbine exhaust can heat hot water.
By using the cO2 in the exhaust to enhance the growth of algae in solar collectors, biodisel and biomass to put back through the fuel cell can be produced. Putting all these systems together would provide liquid transportation fuel as well as a backup distributed generation source for wind, solar, and water power.
The same biogas cycle can be initiated with manure, sewage, garbage, or farm waste as well. Lots of small distributed systems at landfills, farms, sewage plants. and even skyscrapers would provide a great renewable biomass "battery" for the renewable grid.
Dig the green skyscraper with microturbines.
http://thefraserdomain.typepad.com/energy/2007/01/zero_energy_chi.html#comment-28026046
