Chattanooga Project Demonstrates Methane-To-Electric Moment

Methane-to-electric projects are a hot topic in the wastewater sector these days.

“The idea — using methane from sewage waste to generate electricity — seems to be having its moment, with Chicago (with the world's largest wastewater plant) and Los Angeles announcing plans, and Washington, DC, starting up its facility in October. Chicago may add an additional twist — mixing in waste grain from the area's breweries to boost the methane level in its waste,” the Chattanooga Times Free Press recently reported. “Gresham, OR, is doing something similar, using grease and fat trucked in from restaurants in nearby Portland.”

Methane-to-electricity projects have traditionally been challenging, but that’s changing. “The methane produced from wastewater was too ‘dirty’ to burn,” the report said, citing said Jeff Rose, wastewater plant deputy director in Chattanooga, TN. "The industry is just now getting the technology to clean up the gas enough so this is sustainable," he said.

Officials at the Moccasin Bend Wastewater Treatment Plant in Chattanooga are trying to get on board. Officials just got greenlit to apply for funding for a methane-to-electricity project.

What would the Chattanooga project look like? First of all, new equipment would be needed.

“Chattanooga will need to increase its methane production to make the project workable, Mike Patrick, director of the wastewater plant in Chattanooga, said. The site's current digesters are about 12 years old and need replacing. Newer units can produce 600,000 cubic feet of methane every day, making the project cost-effective,” the report said.

Still, funding questions remain.

In December, “the City Council unanimously authorized the Department of Public Works to apply for a Tennessee Valley Authority grant that would pay more than half the cost of a $6.1 million methane-to-electricity project, leaving the city's share at nearly $2.7 million, according to Public Works Director Lee Norris. The methane would be burned, producing steam to turn a turbine and generate electricity,” the report said.

Supporters say the project would have a range of benefits.

The project would ultimately be a cost-saver for the plant, according to supporters. “The electricity generated from the methane would reduce that by $1 million every year, so the payback would be less than three years with the grant, or seven years without,” the report said.

"This takes advantage of waste gas we're going to produce regardless," Patrick said, arguing that the city should move forward, regardless of grant funding. "It is a very green project, and it is economically feasible."

The city could see major benefits, as well. “In the event of a major power outage, it would allow the Moccasin Bend facility to generate a quarter of its electricity needs onsite, keeping at least some of its pumps operating,” the report said, citing Patrick.

Methane-to-electricity projects are sprouting up across the country, from Munster, IN, to Orange County, CA.