Pioneers in Converting Landfill Methane to Electricity
EnviroNZ was the first operator in New Zealand to generate electricity from methane gas produced from the degradation of waste in landfills. We started in 1992 at the Rosedale and Greenmount landfills in Auckland where we had 4 megawatts and 6 megawatts of generation capacity installed respectively.
Today we have 7 megawatts of generation capacity installed at our Hampton PARRC (power and resource recovery centre) facility in the North Waikato, where we produce sufficient electricity to power 5,000 households.
Landfills produce methane gas as a result of the natural anaerobic decomposition of organic refuse. In today’s modern landfill, this gas is managed to ensure safety and protect the environment. The gas is extracted from the landfill under vacuum via a reticulation network and used to fuel engines that generate electricity. Any extracted gas not used to generate electricity is flared.
At Hampton PARRC the electricity produced is transmitted under the Waikato River to Bombay, where it enters the national grid.
The production of gas within landfills typically increases as refuse is placed and then peaks shortly after the landfill’s closure. This is followed by a slow decline over subsequent years. The commercial lifetime of a landfill gas field is typically 10 to 20 years from closure. We still generate approximately 1 megawatt of electricity every hour from the closed landfill at Greenmount some 10 years after its closure.
EnviroNZ is extremely proud of the role we have played in developing innovative gas to energy technology in New Zealand.
Four of the seven gas engines at Hampton PARRC