RALEIGH — The future of legislation agreed upon by renewable energy interests and Duke Energy to extend the utility’s requirements to use more alternative power in North Carolina is in doubt as a key senator repeats his attempts to delay wind energy permits through 2020.

The bill to change how the nation’s largest electric utility purchases electricity through solar, biomass and other options cleared the House earlier this month by a wide margin. Bill managers had warned against making significant changes that could scuttle the agreement, reached after months of negotiations.

But the Senate version of the measure unveiled this week adds a moratorium on wind facility permits sought starting last year by Senate Majority Leader Harry Brown of Jacksonville, home of Camp Lejeune. Brown wants the wait to give time for an outside group to complete maps laying out locations where high-altitude wind farms could pose a threat to jet and helicopter missions and other operations of eastern North Carolina military installations.

With the military comprising the state’s second largest “industry” and a potential round of base closings and consolidations ahead, the state shouldn’t do anything to weaken the military’s capabilities in North Carolina and threaten jobs, Brown told a Senate committee Tuesday.

“Taking a step back to make sure that there’s a balance between the military and wind —making sure that they can co-exist — is important,” Brown said before the new edition of the measure was approved by the committee on a voice vote. “To not protect that (military) resource, I think, would be a huge mistake.”

But these and other changes in the Senate now cause renewable energy and environmental groups to oppose the new measure. They call the moratorium unnecessary and restrictions that would derail two developing pending wind farm projects — one in Perquimans and Chowan counties and the other in Tyrrell County.

Duke Energy spokesman Randy Wheeless said later Tuesday the Charlotte-based utility would prefer legislators stick with the agreed-upon House measure. That bill “struck a very delicate balance for all parties involved with renewable energy in North Carolina.”

The proposed legislation would create a new competitive procurement process for Duke Energy to purchase renewable energy. Despite the Senate changes, Wheeless said the measure should still save consumers $850 million over 10 years in what it would pay for renewable energy.

Betsy McCorkle, a lobbyist for both the North Carolina Sustainable Energy Association and the company developing the Perquimans-Chowan project, told the committee that military and local governments have raises no concerns about the project. Federal permitting already is required. The moratorium threatens the $500 million project, which could create up to 400 construction jobs, she said.

The updated bill “no longer moves our energy economy forward,” McCorkle said. “Instead, it adds a provision that will be costly to ratepayers and deprive rural counties of much needed investment and tax base.”

The measure next heads to the full Senate. Rep. John Szoka, a Cumberland County Republican and sponsor of the previous version approved by the House, urged senators to move the bill along in what’s expected to be the final days of this year’s General Assembly work session so that a compromise can be reached.

A large-scale wind farm near Elizabeth City producing power for Amazon to run its Virginia data centers is now operating and wouldn’t be affected by the moratorium.

Some legislators, including House Speaker Tim Moore and Senate leader Phil Berger, had written President Donald Trump’s administration urging it to shut down the wind farm because of its proximity to a radar installation. Still, Moore helped kick-start negotiations last year that resulted in the House bill.