Biogas forms as a result of biological processes in sewage treatment plants, waste landfills and livestock manure management systems. The biogas can be captured and burned for electricity generation.
MGE purchases electricity from the Dane County Rodefeld Landfill where generators run on methane gas. Dane County taps into the methane gas produced naturally in the landfill. The generators export the energy to MGE's distribution system. On average, the Rodefeld generators produce more than 31 million kilowatt-hours (kWh) per year, or enough electricity to serve nearly 4,800 homes.
Collecting and using landfill gas reduces the amount of methane that is released into the air. Methane is one of the greenhouse gases associated with global climate change.
MGE will take energy from an innovative manure digester that will be run by Dane County to power homes and businesses and to help clean area lakes. The digester is located on a farm in the town of Springfield near Middleton. It will convert cow manure from local farms into electricity. Construction began in May 2013.
MGE will purchase this electricity from Dane County at a cost of over $1 million annually. This locally produced renewable energy will significantly reduce phosphorus runoff into local waterways and improve water quality. Currently, most of the phosphorus from these farms discharges to the Yahara Watershed causing green algae and other weed growth in Dane County's lakes.
The manure digester will generate 11 million kWh of electricity annually which is enough to power approximately 1,600 homes. The energy will be added to MGE's community energy grid.