State legislators Monday backed off a provision in an energy bill that would have benefited a New Jersey company that is planning to buy an aging power plant in Salem and replace it with a new, cleaner-burning generator.

The initial provision was intended to make it easier for power companies to close older electric plants that were fueled by coal or oil and replace them with modern generators that emit less pollution. Utilities would have been required to enter into long-term contracts with those new facilities built on the sites of closed coal- and oil-fired plants.

That language would have benefited Footprint Power LLC, a New Jersey company that is planning to purchase the 60-year-old Salem Harbor Power Station, scheduled to be closed in 2014, and build a state-of-the art gas-powered plant in its place.

But Massachusetts lawmakers Monday agreed to amend the provision after criticism from environmentalists and competitors in the power industry that it gave an unfair advantage to Footprint. Now the provision simply allows state regulators to prod utilities into long-term contracts with power plants if they determine the Boston area and North Shore need more electricity supplies.

The legislation includes other benefits, including extended tax subsidies, to help Salem deal with the potential loss of the power station, its largest taxpayer.

Footprint Power could not be reached for comment. But the state representative who had sponsored the original language said he was pleased with the compromise because it accomplishes the same goals: cleaning up the power plant site and protecting Salem’s tax base.

“It gets to the points we were trying to get to — which was stabilize the property tax and clean up the property,” John D. Keenan, a Democrat from Salem, said Monday just before the House of Representatives took up the energy bill. “And hopefully, if necessary or needed, there will be a power plant built there as well.”

But some opponents of the original provision were unhappy with the amended language because they suspect it will still lead to Footprint getting a long-term utility contract.

“All those things are steps in the right direction but it’s a fundamentally flawed policy overall,” said Dan Dolan, president of the New England Power Generators Association, a regional trade group of electric-plant owners. “It’s still something that’s going to [result in] an out-of-market contract.”

But having lost the political battle before the Legislature, Dolan said his members will now concentrate on pressing state regulators not to show favoritism to Footprint.

The energy bill awaits Governor Deval Patrick’s signature.