ALBANY, N.Y. – New York officials have released preliminary draft rules for implementing the Regional Greenhouse Gas Initiative to cut power plant emissions of carbon dioxide, which are considered a major contributor to global warming.

Seven Northeast states, including Maine, agreed to set up a system designed to cut greenhouse gases through a cap-and-trade system of emission permits that would cover electric generating units with a capacity of 25 megawatts or more.

States would issue one allowance, or permit, for each ton of CO2 emissions allowed by the cap. Companies that do not have enough allowances to cover CO2 emissions must either reduce their emissions or purchase allowances.

New York’s Department of Environmental Conservation this week issued a proposed draft rule that includes the auction of 100 percent of emissions allowances on the open market, an approach urged by some environmentalists. Public comments are due by Jan. 12.

Regional emissions of carbon dioxide would be capped at current levels – about 121 million tons annually – from 2009 to 2015. Incremental reductions over four years would then aim to curb emissions by 10 percent by 2019.

Other states that signed the regional memorandum of understanding for the initiative RGGI are Connecticut, Delaware, Maine, New Hampshire, New Jersey and Vermont.

The Maine Department of Environmental Protection will hold a fourth and final workshop on Dec. 19 before DEP staff present their recommendations on the draft rules to the state Legislature.

The staff is still debating whether to auction off 100 percent of the emissions allowances or give some away.

“New York State has proposed an innovative, consumer-friendly approach to distributing the emissions allowances that power plants will need to help curb pollution that contributes to climate change,” state Department of Environmental Conservation Commissioner Denise Sheehan said.