HARRISBURG - Gov. Tom Wolf’s administration wants the centerpiece of the Democrat’s plan to fight climate change to take effect immediately, but it is being held up in a growing legal dispute by an agency that answers to the Republican-controlled Legislature.

On Friday, Wolf’s secretary of environmental protection, Patrick McDonnell, wrote to the Legislative Reference Bureau to insist that it publish Wolf’s regulation to impose a price on carbon dioxide emissions from fossil fuel-fired power plants.

Publishing it in the Pennsylvania Bulletin would mean the regulation takes immediate effect, and would make Pennsylvania the first major fossil fuel state to adopt a carbon pricing policy. The bulletin is published weekly as an official record of actions by government agencies.

However, Republicans who control the Legislature oppose the regulation and argue that they have more time, months even, to take votes on it. McDonnell wrote that the legislative review period has expired and that Republicans’ interpretation of the law is wrong.

“It is a violation of the separation of powers doctrine, unnecessarily impeding the executive branch’s ability to execute its rule-making authority,” McDonnell wrote.

House and Senate leaders, however, did not back down Monday from their interpretation of the law and its timeline.

Lawmakers ultimately cannot block the regulation unless they are able to muster a two-thirds majority, which they have been unable to do.

The plan has won approval from regulatory bodies and signoff by the governor’s office of general counsel and the attorney general’s office under reviews for form and legality.

It still could face a legal challenge in the courts from opponents, who contend that it is an illegal use of regulatory authority.

The regulation allows Pennsylvania to join a multistate consortium, the Regional Greenhouse Gas Initiative, which sets a price and declining limits on carbon dioxide emissions from power plants.

Under the cap-and-trade program, dozens of power plants fueled by coal, oil and natural gas would be forced to buy hundreds of millions of dollars in credits in the coming years that the state could then spend on clean energy efforts.