Dive Brief:

• Lawmakers in the Montana House on Tuesday rejected legislation that would have allowed NorthWestern Energy to purchase more energy from the coal-fired Colstrip plant a day after they gave the bill preliminary approval. 
• Environmental advocates say the vote caught them by surprise and it was unclear why the measure failed. Several conservative Republicans who had supported the bill reversed their vote, according to the Associated Press.
• NorthWestern declined to comment on the bill's defeat. The utility owns 222 MW of Colstrip 4, a 778-MW unit, and SB 331 would have allowed it to add a 150 MW share. 

Dive Insight:

Debate over the Colstrip bill is the latest in a string of state efforts to preserve retiring coal generation. Its rejection came just one day after a preliminary vote on the matter passed 62-38.

Environmental advocates called SB 331 "a terrible deal for NorthWestern customers," but after the Montana Senate approved the measure in March and the House gave an initial thumbs-up Monday, the measure was expected to pass.

Speaking just after the vote, Anne Hedges, deputy director and lead lobbyist for the Montana Environmental Information Center, welcomed the result.

"Yes, this was a surprise," she said, adding it's still not clear what changed the tide.

"There was a revolt. ... The Republicans finally figured out that this bill was toxic. It was anti-consumer and anti-constituent. It was going to raise utility bills, and that's a tough thing to run on," she told Utility Dive. "This bill was unanimously disliked outside the walls of the Capitol."

A NorthWestern official said the utility was still tracking activity on the bill and could not comment.

Like many coal plants, plans are being made to permanently close Colstrip. SB 331 was known locally as the "Save Colstrip" bill. 

According to Hedges, there are still ways the legislation could be resurrected and there are one or two bills that could be "hijacked" by supporters of the Colstrip legislation.

Puget Sound Energy and Talen Energy co-own Units 1 and 2 of Colstrip, which are scheduled to be closed by 2022. PSE, Talen, Portland General Electric, Avista Corp., PacifiCorp and NorthWestern Energy co-own Units 3 and 4, which are slated to be shuttered by 2035 or sooner.

Tuesday's vote was a win for environmental advocates, but Hedges said there is no guarantee the legislation wont come back up.

"There is certainly the possibility they attach it to a different bill. There are two weeks left in the session, and this is the time when mischief occurs," Hedges said. But, she said it appeared lawmakers had come to an agreement on the bill. 

"Every once in a while, left meets right."