Several businesses and municipal facilities already use fuel cells to make electricity and heat from biogas. When organic matter decomposes, it produces a greenhouse gasA gas in Earth's atmosphere that traps heat and can contribute to global warming. Carbon dioxide and methane are two GHGs. that is mostly methane and CO2. In some instances, like at landfills, the decomposition takes decades and the GHG releases slowly. In other places, such as agricultural processors and wastewater treatment plants, biogas is quickly produced as a result of anaerobic digestion, a process that uses microorganisms to stabilize wastewater before final disposal.

Companies and municipalities are aware that releasing biogas has environmental consequences, and that biogas can be a source of energy. To reduce the GHG impact, some facilities flare the biogas; simply burn it without harnessing the energy. Other facilities burn the biogas in a combustion engine to produce electricity, a process that is about 20% efficient. Several municipalities and businesses are using their biogas in a high-temperature fuel cell to produce electricity and heat, a process that is almost 50% efficient. When they recover and use the waste heat, the efficiency nears 80%.

The City of Tulare, California, installed a 900 kW molten carbonate fuel cell as a combined heat and power system. It produces heat and power, generates 40% fewer greenhouses gases than grid electricity and has 97% availability. (Recently, Tulare purchased a second fuel cell, bringing their energy output to 1 MW.) The City expects a return on its investment in less than five years. Sierra Nevada Brewing Co. estimates that its biogas fuel cells save $400,000 a year in electricity costs.

The next step is a tri-generation system introduced by and developed at the National Fuel Cell Research Center at the University of California, Irvine. It is a high-temperature fuel cell that produces heat, electricity and hydrogen on demand. FuelCell Energy is beta-testing the first unit, which will be installed soon at Orange County Sanitation District in Fountain Valley.

Using biogas from the wastewater treatment plant, the tri-generation system will create heat for treating wastewater, 300 kW of green power for the pumping stations and up to 135 kg of renewable hydrogen for fuel cell vehicles every day.  The project is a collaboration between Air Products, FuelCell Energy and the NFCRC, and co-funded by  the U.S. Department of Energy, California Air Resources Board, and South Coast Air Quality Management District with contributions from Sempra Energy.

Fuel cells operating on biogas offer a pathway to renewable electricity generation. With federal incentives of $3,500/kW or 30% of the project costs and the California Self Generation Incentive Program that provides $4500/kW for fuel cells using renewable feedstock, businesses and municipalities can achieve a reasonable payback period of less than five years while reducing GHG emissions and providing green energy and fuel.