By Danny Bernardini
Posted: 10/13/2009
Garbage trucks from Solano and San Mateo counties dump their loads at the Potrero Hills Landfill in Suisun in September. (Rick Roach / The Reporter)
The folks at Potrero Hills Landfill have signed an agreement to turn waste into watts.
After signing a 25-year contract with DTE Biomass Energy, Waste Connections Inc. on Monday announced it would eventually start converting methane gas into electricity that will power about 7,000 homes per year.
It isn't known exactly how long it will take to get the operation up and running, but the Suisun City landfill should be producing energy in two or three years, said Worthing Jackman, chief financial officer for Waste Connections.
He said the effort falls right in line with California's goal of becoming a leader in renewable energy. He said it also helps the landfill, which is responsible for getting rid of the methane gas one way or another.
Waste Connections operates 17 renewable energy projects across the country.
"This is one of the avenues between wind and solar," Jackman said. "You do it anyway because it makes sense. Clearly it's a more established business lately."
Most of the details, above harvesting the gasses, will be handled by DTE and it is believed the energy would ultimately be generated by turbines. Those turbines would be fueled by the collected gas, which is now burned off as waste, said Steve Bouck, president of Waste Connections.
Bouck explained the process as beginning with sinking wells into the trash heaps. That can only be done at locations that have had trash stored there for a significant amount of time so enough methane is produced. Damp conditions also increase the amount of gas created.
The gas is then piped upward into headers, before being forwarded on to mechanisms provided by DTE. It goes through chemical processes before being condensed enough to ignite and power the turbines, which charge a generator.
"You're mining it out of the landfill. There is a series of steps it goes through to make it a fuel," Bouck said.
DTE will make a deal with power companies to transmit the electricity, completing the transition. "They will be responsible for getting that into the grid," said Bouck.
DTE, with headquarters in Michigan, has been in the landfill energy business since 1988, operating 25 sites in 14 states.
Using the methane to create electricity is a responsible thing to do, Bouck said, explaining that the methane gas has to be disposed of anyway, before it leaks into the environment. The normal method, he said, is to burn it in a process called "flaring."
"Methane was actually a problem, it would leak off site. It was an issue," he said. "Initially people collected it to flare it. Now you have a wonderful energy source you are flaring."
