The Supreme Court’s recent ruling against the EPA’s mercury regulations came as much-needed good news for Tri-State Generation and Transmission, Colorado’s second-largest electricity provider.

Tri-State filed an emergency motion July 31 asking for a special exemption from the 2012 Mercury and Air Toxics rule for its 110-megawatt coal-fired Nucla Station. The energy co-op has until Sept. 1 to decide whether to spend millions to install a pollution-control device on the seldom-used plant or to shut it down at a future date. In April 2016, the new control equipment would need to be installed, or the plant would be unable to operate.

On June 29, however, the court ruled that the EPA cannot ignore cost when determining which power-plant regulations are “appropriate and necessary” under the Clean Air Act.

In its motion, Tri-State asked for a suspension of the compliance obligation “unless and until the EPA makes a new ‘appropriate and necessary’ finding.”

The Nucla Station “has the lowest mercury emissions rate of any coal-fired unit in the country and easily meets the MATS standard for mercury,” but not for HCI.

Rural residents already pay more for their energy than customers in urban and suburban areas and many of Tri-State’s customers in Colorado, Nebraska, New Mexico and Wyoming are already having trouble making ends meet, the power company pointed out.

“Requiring these customers to pay even more for their electricity would be a substantial hardship given that a significant percentage of Tri-State’s residential customers live at or below the poverty line,” Tri-State argued.

“Such customers would be irreparably harmed if Tri-State is forced to purchase new equipment unnecessarily and they must help to pay the cost,” the motion said.

Tri-State is fighting to save its Colowyo coal mine from a court order that threatens to shut it down. In a video released last week by the American Energy Alliance, miners and Moffat County residents defended the mine’s environmental record and stressed its economic importance to the region.

– valrichardson17@gmail.com

CORRECTION: Tri-State would have to install new equipment by April 2016 or shut down the plant. A prior version of this story had an earlier potential shut-down date.