CASPER — An effort by lawmakers to defend Wyoming’s leading industry gained ground Monday after a pair of bills aimed at slowing coal plant closures cleared the House.

Wyoming is the nation’s leading producer of coal. For years, the state’s thermal coal resources have been burned to make electricity for Americans. But since peaking around 2008, coal production in Wyoming has been declining, with annual production now about half what it was just a decade ago.

Inexpensive natural gas and renewable energy can also be used to create electricity and have gradually taken over the electricity market. Utilities tend to favor the commodity that is cheaper.

The drag on coal demand has hit Wyoming particularly hard. The state relies overwhelmingly on fossil fuel production to fund its budget each year.

Two bills passed by the House on the 23rd day of Wyoming legislative session in an attempt to slow this trend.

If passed into law, House Bill 166 would require utilities to take additional steps before they can receive approval from state regulators to retire aging coal or natural gas plants.

That includes providing evidence to the Public Service Commission that closing a coal or natural gas unit would deliver “significant cost savings” for customers and not threaten power reliability.

In other words, the bill will not allow the state commission to give a green light to fossil fuel plant closures unless the utility can present a certain amount of proof in support of the action.

Rep. Steve Harshman, R-Casper, sponsored the bill.

During comments provided at a committee meeting, state regulators emphasized the Public Service Commission already had the obligation to make sure utilities provide customers power at “just and reasonable rates.”

Another piece of legislation advanced on Monday, House Bill 207, would give half a million dollars to Wyoming’s governor and attorney general to potentially sue other states restricting the import or use of Wyoming coal.

Bill sponsor Rep. Jeremy Haroldson, R-Wheatland, initially proposed allocating $1.2 million to the effort. But the House Appropriations Committee only approved $500,000 from the general fund after voicing concerns over the bill.

Wyoming has already a lawsuit pending against Washington, alleging the state violated the interstate commerce clause by blocking the development of a coal export terminal.

The Senate still needs to vote on the proposed pieces of legislation before they have a chance to become law. Senate leadership assigned the two bills to the Minerals, Business and Economic Development Committee on Monday.

Another bill also proposed this year to save Wyoming coal, House Bill 155, was advanced from committee. This bill would ask state regulators to analyze how closing a coal or natural gas power plant could affect grid reliability in Wyoming and nationwide before giving a company the OK to retire it. Prior to giving a utility company permission to shut down an aging power plant unit, state regulators would have to consider whether the closure would increase the risk of power outages.

The bill passed its first reading Monday evening.