According to Dane County Executive Joe Parisi, the landfill used by the city of Madison should have already reached capacity.

“We were reaching capacity, we had about two to three years left on the landfill when I was elected about 3 1/2 years ago,” Dane County Executive Joe Parisi said.

Dane County’s Rodefeld Landfill broke ground on an expansion project this week in an effort to increase longevity and decrease environmental impact from waste emissions.

The landfill, located in the town of Cottage Grove off of Highway 12, will include new features such as gas extraction, electricity conversion and a facility to extract waste.

According to a statement from the Dane County Executive Office, the expansion will cost $20 million and extend the life of the landfill for another 30 years. The alternative was siting a new landfill, which would have cost more than $100 million and taken nearly a decade to develop. The process could have also resulted in the loss of at least 200 acres of prime farmland, the statement said.

Ald. Mike Verveer, District 4, said Madison has depended on the county landfill for many years, and the city’s streets division has been the largest customer of the landfill for several decades. Verveer said last year the city and the county negotiated jointly to expand the landfill, partly because some Madison park land is included in the expansion.

Parisi said there are two county buildings being built across the street from the landfill: a medical examiner’s office and a highway garage. Heat collected from waste materials will be used to heat the buildings through a piping system.

Another unique feature of this landfill is the way collected methane gas will be utilized. Verveer said Madison has been collecting methane on the site for years already, but now through the expansion, the methane will be used to create energy and fuel county vehicles. The stored methane will be located at the highway garage and used as a fuel stop.

The landfill will also look to improve clean energy efforts by utilizing renewable energy production. According to the statement, the expansion allows the county to nearly double its production of renewable energy from decaying trash at the Rodefeld facility. The landfill currently generates $3.3 million in electricity annually that is purchased by MG&E, which is enough to power 4,000 homes.

The energy savings will be shared by Madison residents and students as the plant produces recycled energy more efficiently, Parisi said.

“This will help lower energy costs for people in Dane County. We are saving money on energy, and we earn money on electricity we sell at the landfill,” Parisi said. “We are one of the greenest, hardest-working landfills in the state.”