Energy regulators from four U.S. states have signed an agreement on to cooperate to promote energy efficiency and reduce greenhouse gas emissions from power plants, Reuter’s reports.

The move by the public utilities commissions of California, Oregon, Washington and New Mexico is likely to draw in other states in the West, officials said.

Michael Peevey, president of the California commission, said the Western states “can’t wait for the feds” to work for emissions standards, energy efficiency programs and more renewable energy.

California is the only state that has ordered caps to reduce greenhouse gas emissions, by 25 percent by 2020, and the state is working on forming a cap-and-trade program with market-based emissions trading.

Peevey said California is studying a regional emissions trading system being formed by eight states in the Northeast and Mid-Atlantic – the Regional Greenhouse Gas Initiative.