During anaerobic digestion, digester gas is produced which is approximately 50 percent methane, a valuable fuel. This digester gas is predominately used to generate electrical power using two 350 kW CAT biogas engine generators housed in the Energy Recovery Building. Waste heat, a by-product of power generation, is recovered from the engines and exhaust to heat the digesters..
The electricity and heat which are produced by the cogeneration system are utilized in the plant to reduce purchased electricity and natural gas. Electricity produced by the generators is fed into the plant electrical distribution system for use where needed. Heat from the gas engines is recovered and used for heating the digester and the Energy Recovery Building. Over 90 percent of the plant’s electrical need is met by the onsite generation of electricity. Due to existing regulations, excess power cannot be exported off premise to the grid.