Elegant as this solution is – eBay is using natural gas, true, but it's using natural gas as efficiently as possible – it only highlights the challenge of running fuel cells on biogas. Even directed biogas can be hard to come by in the U.S., despite the fact that potential sources are abundant. The National Association of Clean Water Agencies estimates that energy generated at U.S. wastewater treatment plants could meet as much as 12 percent of U.S. energy demand.
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Germany is the world's biggest user of biogas, which accounts for around 4.5 percent of the country's electricity, typically generated using combustion motors. That's a solution with modest capital costs, but FuelCell Energy, the fuel cell provider for the Wyoming project, notes that generating electricity by burning biogas isn't as efficient as using biogas in an electrochemical reaction, nor as clean.
Don Collins of the Western Research Institute, a participant in the Wyoming pilot project, highlighted another potential advantage of using fuel cells: Certain types of fuel cells can capture carbon dioxide and deliver a very pure CO2 stream, which could theoretically be utilized to take the whole system from zero to negative carbon emissions.
—Pete Danko, Breaking Energy