Nine northeastern US states are said to have reached a preliminary agreement to curb power plant carbon dioxide emissions.

The initiative, led by New York Governor George Pataki and launched in 2003, will see emissions levels frozen at current levels from 2009 to 2015 and subsequently reduced by 10% by 2020 under a cap and trade system.

With some 600 generation facilities spread across the nine states of Connecticut, Delaware, Maine, Massachusetts, New Hampshire, New Jersey, New York, Rhode Island and Vermont, concerns have been raised that the scheme could boost power prices, although this could be offset by the proceeds from the sale of emission allowances, with some considering selling 20% or more of the allowances.

Initially, the so-called Regional Greenhouse Gas Initiative would see emissions capped at 150 million tonnes of carbon dioxide a year, roughly equal to the average emissions in the highest three years between 2000 and 2004.

Pataki said there had been “a tremendous amount of progress” on the proposal, but warned there was still work to be done before the deal could be finished. State officials have given it preliminary approval, but some details are still unresolved and legislatures of the nine states would need to approve the scheme for it to move forward, a process that could begin early next year. One issue to be resolved is thought to be how pollution allowances will be allocated and companies are also understood to be concerned about proposed restrictions limiting their ability to import power from coal-fired plants located outside the regional pact.

Nonetheless, a number of states have already sued coal-fired generators in the Midwest over air quality problems seen in the east of the country. And, elsewhere, California, Washington and Oregon are also thought to be exploring a similar regional programme. Representatives of the three plan to meet in Sacramento in mid-September to hammer out the details.

Meanwhile, with the states acting independently of the federal government, the administration is busy forging its own path with regard to emissions control. The US-backed Asia-Pacific Partnership on Clean Development and Climate signed by the USA, Australia, China and India among others is being perceived by some as a serious threat to the Kyoto Protocol, the international treaty on climate change that is deeply opposed by the US administration.

With signatories to the Asia Pacific Partnership due to hold a first ministerial planning meeting in November, concerns have been raised for the Kyoto process to succeed post-2012. For Kyoto to combat climate change, agreement on more substantial cuts after 2012 involving developing as well as industrialised nations is crucial, but although only six nations have joined the Asia Partnership they account for around half of global energy use and emissions and their technology-led approach to climate change dramatically differs from the Kyoto Protocol’s mandatory emission reduction targets with legally binding reduction targets.