David Michael Miller
Dane County was one of the first in Wisconsin to begin using the methane its landfill produces to generate electricity.
“We actually produce enough electricity on our landfill to offset almost all electric use by Dane County operations, all Dane County functions countywide,” says John Welch, solid waste manager at Dane County landfill.
However, this is not what the electricity is used for. Dane County has a 10-year contract with Madison Gas and Electric, selling the electricity to it for about $3 million a year, Welch says.
As that contract comes to an end, Dane County is hoping to get a better deal. A proposed $18 million project in the 2017 budget would allow the county to turn the methane the trash produces into compressed natural gas, or CNG. That fuel could then be sold. It might even get piped to California, which is the leading market in the United States for the gas.
Dane County Executive Joe Parisi wants the project to be a model for fighting global warming.
“I funded this project in my 2017 Dane County budget because I want our county to be a national leader on confronting climate change, embracing green energy, and taking steps to cleaning the air we breathe,” Parisi said.
There are currently about 3,000 active landfills in the United States. About 80 of these are in Wisconsin. Most of Wisconsin’s landfills have been producing electricity for the past decade or two, but in low amounts.
Dane County’s landfill has been generating electricity for 26 years, currently enough to power 4,000 Dane County households, 24 hours a day.
That methane is produced by a steady stream of garbage — mostly household waste — that the county takes in. “We receive about 220,000 tons of waste per year or 700 to 800 tons of trash per day,” Welch says. “In the summer on a busy day this total can reach 1,500 tons.”
As this waste breaks down in the landfill, it produces a variety of gases, 55 percent of which is methane. Released into the atmosphere, it would contribute to global warming. But it is also valuable as fuel.
The county already converts some of its methane into CNG to fuel its fleet vehicles. “To date, we have acquired 65 vehicles that run on CNG, and by the end of next year will have 19 heavy-duty plows on the road running on carbon-friendly CNG,” Parisi says.
The county plans to continue fueling its vehicles with the landfill gas, but Welch says there’s still plenty of methane left over for other uses.
“We really think we’re creating a template for other communities to follow suit so collectively we can reduce carbon emissions and expand the use of biofuels as a viable, cleaner alternative,” says Parisi.
Dane County’s contract with MGE expires within the next two years. Welch says the county’s new plan for the gas will likely be more lucrative than the $3 million the utility now pays for it.
“We asked ourselves, ‘What can we do with our gas? How can we plan for the future of being able to continue to use our gas as a resource?’” Welch says. “We determined that the best use would be to take the gas and instead of using it in engines, we clean it up so our methane is pure.”
A natural gas pipeline owned by TransCanada runs directly underneath a portion of Dane County landfill’s property, but not directly under the actual waste. Welch says easy access to this pipeline is something the county can capitalize on.
“Then we can inject it into the pipeline to displace fossil fuel/natural gas,” Welch says. “The pipeline goes to California, and the methane will then be used [there] for vehicle fuel.
“Based on our projections, we believe we can sell over 2 million gallons equivalent of CNG each year, earning renewable energy credits and low carbon fuel standard credits without impacting the ability to power our growing county fleet that runs on CNG,” he says.
The methane Dane County landfill produces now is about 50 to 55 percent pure, Welch says. However, the methane used to power home furnaces is 95 to 98 percent pure.
In order to make the landfill’s methane purer and more marketable, the county needs to purchase new equipment. The 2017 county budget includes an $18 million project devoted to creating a purification system.
“We’ve hired a consultant and are reviewing proposals from vendors interested in selling us the equipment needed for the project,” Parisi says. “This new clean fuel program could earn county taxpayers millions a year in new revenue and reduce carbon emissions by 30,000 tons per year.”
Welch hopes to have the purification system in place before the contract with MGE expires in 2019. Ideally, the system would get approval from the Environmental Protection Agency in early 2019, Welch says.
“The goal is to leave the Earth a little bit better than how we found it,” Welch says. “I think it’s irresponsible to not think that way.”
