The New York Power Authority is testing a fuel cell power plant which burns the gas produced at a sewage plant. Tests on the fuel cell, which has been operating since May, show that levels of pollution emitted during power generation are significantly lower than those produced when the gas is flared.

The 200 kWe phosphoric acid fuel cell, built by ONSI Corp, is being tested at the Westchester County Wastewater Treatment plant in Yonkers. It burns anaerobic digester gas.

Preliminary measurements by the Environmental Protection Agency show that emissions of carbon monoxide and volatile organic components were below the detection limit of 0.5 ppm. Nitrogen oxide emissions were 0.4 ppm and sulphur dioxide emissions were 1 ppm.

A key part of the Yonkers installation is a prototype gas processing units which removes sulphur and moisture from the digester gas before it reaches the fuel cell, leaving only methane and carbon dioxide. Based on the performance at Yonkers, the US Department of Energy has awarded grants for similar projects in Oregon and California.