A roaring fire that consumes Twin Cities trash every year may soon be extinguished, sending mountains of extra waste into the metro area’s landfills.

Great River Energy (GRE) says it will close its Elk River waste-to-energy operation if no one steps forward to buy it by this fall. The two likeliest bidders — Anoka County and Hennepin County — aren’t interested. If the incinerator and metal recovery facility close, more than 250,000 tons of extra trash will likely head instead to the region’s landfills.

Burying more municipal trash is the opposite of what state environmental officials want — they prioritize burning refuse that isn’t recycled or composted. Garbage incineration comes with its own pollution concerns, but state regulators say Minnesota’s burners meet rigorous federal pollution standards while extracting recyclables and energy that are otherwise lost.

Plus, they argue, tossing trash in the dump doesn’t make it go away.

“The land that’s going to be taken up by landfilling … that’s going to be a legacy we’re going to leave to our grandchildren,” said Sig Scheurle, planning director with the Minnesota Pollution Control Agency (MPCA).

The other primary trash incinerators that serve the metro area are already operating at capacity. Twin Cities trash that doesn’t get burned ends up mainly at four landfills in Elk River, Burnsville, Inver Grove Heights and Glencoe. They took in a million cubic yards of compacted municipal trash last year, enough to fill the IDS Center tower about 1.5 times, according to a Star Tribune analysis of MPCA data.

If Great River Energy shuts down its burner, state regulators expect the four landfills to reach their permitted capacity in just over six years — more than two years earlier than anticipated — since haulers will have few other alternatives. Landfills must ask the state for additional allowed space, and two have already indicated they will.

“As much as anybody, I would love to see the plant stay in operation and do the environmentally responsible thing and avoid landfills,” Anoka County Commissioner Jim Kordiak said at a recent board discussion. “But there are too many pitfalls.”

Despite the state’s emphasis on incineration vs. landfilling, the economics of GRE’s trash-to-energy project have become unsustainable. Anoka County helped create the facility in the 1980s and, along with two other counties, subsidized the incinerator for years so it could compete with cheaper landfills.

Those subsidies have disappeared, and wholesale electricity prices are low. Now the burner can’t earn enough from the electricity it generates or attract enough garbage from haulers to stay viable, said Tim Steinbeck, GRE’s director of resource recovery. Great River Energy, which has owned the facility since 2010, is a cooperative energy company with member owners.

“We’re hoping others step up and want to keep it going,” Steinbeck said, adding that it will close early next year without a buyer. He said some private parties have expressed interest but declined to say who they were.

County commissioners in Anoka and Hennepin have been reluctant to take on a project that GRE had trouble keeping afloat.

“For Hennepin County it’s not economical to step up and try and keep this facility going that the private sector apparently could not keep going,” said Hennepin County Board Chairwoman Jan Callison. The county’s own trash burner, in Minneapolis’ North Loop, runs at capacity.

The county is pursuing some of the most aggressive efforts in the state to steer recyclables and organics out of the trash, and Callison said it aims to keep trash out of landfills until all other options have been exhausted.

“It’s going to be a little bit harder for us to achieve that without having GRE as a resource,” Callison said.

About half of the seven-county metro’s waste was recycled or composted last year, according to MPCA data. Another 23 percent was landfilled and 28 percent was burned.

In its most recent plan for managing the metro area’s garbage, completed last year, the MPCA aimed to reduce landfilling to just 2 percent by 2020.

“It’s not just that we’re going backwards in terms of meeting the goals to landfill less waste,” Scheurle said. “We’re also losing the recovery of metals and electricity that we derive from the waste.”

Yet burning garbage has its own critics, due to pollutants like nitrogen oxides and sulfur dioxide that the plants release into the air.

“We know that has very real health consequences,” said Margaret Levin, executive director of the Sierra Club North Star Chapter. “So from a public health perspective, there are serious concerns both with combustion of solid waste and with landfilling.”

State officials recently became more aggressive about diverting trash from metro landfills. The MPCA began enforcing for the first time a 1980s-era law that bars landfilling metro trash that could be incinerated. It fined local landfills, citing the unused capacity at GRE’s burner in Elk River.

Metro landfills — owned by corporate giants Waste Management and Republic Services — sued to block the effort. In April, a district judge agreed with their arguments that the MPCA had improperly punished landfills. An appeal is pending.

State officials will likely have to decide in the coming years whether to grant additional landfill space for municipal trash.

Pine Bend landfill in Inver Grove Heights recently won city consent to amass additional trash on a steeper slope, which will likely need state approvals. And Waste Management has told the MPCA it intends to seek more space at its Burnsville landfill.

“That has been Waste Management’s business plan for a long time,” said company spokeswoman Julie Ketchum. “It has nothing to do with the situation at GRE.”

Burnsville will have a meeting about the plan Oct. 15.