Fuel cells generate electricity using an electrochemical reaction, not combustion, so there are no polluting emissions, only water and heat as by-products. Many fuel cells are fueled with hydrogen, which can be derived from a wide range of traditional and renewable sources, including biogas.
Many facilities, such as wastewater treatment plants (WWTP), landfills, food/beverage processing facilities, wineries, breweries, dairies, large industrial factory farms and confined animal feeding operations (CAFOs), generate tons of organic waste as a byproduct of daily operations, be it sewage, effluent, food or animal waste, all of which can be expensive to remove and burdensome to store. These sites often use an anaerobic digester to convert the organic waste into methane or anaerobic digester gas (ADG), and then burn the ADG, in a combustion-based generator or flare it into the atmosphere to dispose of it. Although ADG is considered carbon-neutral since it is derived from an organic (non-fossil) source, flaring or burning leads to releases of direct and indirect GHGs and other air pollutants. Since ADG contains hydrogen, which is the fuel of choice for fuel cells, a cleaner, more efficient option is to use the gas in a fuel cell to generate electricity and heat for the plant, following a gas cleanup step.