Residents of the Des Moines metro area will soon be receiving more renewable electricity from Polk County’s methane gas recovery facility. In a partnership with Waste Management, the county has green-lighted a $7 million expansion of its waste-to-energy plant located at the Metro Park East landfill. The new expansion will double the amount of electricity produced through the burning of landfill gas in the region.

Many locals view the expansion as a positive addition to the region’s renewable energy profile. The process of extracting and using the landfill’s methane gas is viewed as a sustainable energy alternative due to its low greenhouse gas emissions. And the only waste byproduct from the process is the trash from Des Moines’ dumpsters; a byproduct that is already secured and decomposing inside the landfill.

Cross-sectional diagram of a landfill gas extraction well.

Cross-sectional diagram of a landfill gas extraction well.

The original facility was built 20 years and was designed to produce 6 megawatts of electricity at peak capacity. But the facility is currently collecting more methane gas than it has the capacity to burn, prompting the creation of a second plant to handle the huge volume of gas churning up from the site.

Waste Management operates the Metro Park East landfill plant through a lease with the Metro West Authority which oversees energy and waste disposal operations in the Des Moines area. WM currently pays $250,000 a year to operate the current facility, and will most likely pay double to the MWA once the second plant is online.

The facility will be built with three 20-cylinder engines at the start and will be capable of generating 4.8 megawatts of energy. But room will be set aside for an additional engine that will put the facility at a maximum capacity of 6.4 MW. Each engine is purpose-built for burning methane gas, as opposed to liquid gasoline. The resulting energy is used to drive an electric turbine that generates the electricity. This electricity can then be transferred to the region’s electric grid for distribution.

There are several other landfill gas extraction plants operating in the state of Iowa, with many more planned. Waste Management itself operates over 140 such facilities nationwide, putting it in a prime position to capitalize on the renewed interest in renewable energy. As more states and municipalities look for new ways of creating cheap and low-emission electricity, they will ultimately end up looking at turning their landfills into power plants.

Source via: Des Moines Register