The US is fast developing green hubs, with states on the Atlantic and Pacific seaboards offering far more comprehensive environmental strategies than those in the Midwest and the south of the country.

That is one of the key findings of a new report from think-tank Environment America, which assessed individual state's adoption of renewable energy standards, clean car programmes, utility energy efficiency programmes, energy efficiency standards for appliances and building energy codes.

It found that just seven states – California, Connecticut, New Jersey, New York, Oregon, Rhode Island and Washington – had adopted strong policies in at least four of these areas. Meanwhile, just Massachusetts, Maryland, Maine, Pennsylvania and Vermont were highlighted as "silver star" clean energy states for adopting strong policies in at least two areas and meaningful policies in one to two others.

The report suggests a polarisation of US environmental policy, with clusters of states in the west and east adopting comprehensive climate change legislation, while the state governments in the rest of the country have made considerably slower progress. The findings are likely to further fuel calls from business leaders, frustrated by the prospect of a costly patchwork of different environmental policies, for a more unified environmental regulatory framework across the US.

Environment America executive director Margie Alt said that the findings highlighted the need for wider federal legislation to tackle climate change. " These states are rising to our nation's energy challenge, reducing energy consumption and promoting clean renewable energy," she said. "[But] while the states can and should do even more to meet our energy challenges, it's time for Congress to… deliver a strong energy bill this year."

Dave Hamilton, director of the Sierra Club's global warming programme, which contributed to the research, agreed that Congress should adopt many of the measures already being deployed by the leading state governments. "Congress can flip the switch on America’s clean energy future by increasing fuel economy standards to at least 35 MPG and requiring that we get 15 per cent of our electricity from clean, homegrown sources like wind, solar, and biomass by the year 2020," he said.

The report comes as a new study from the US Environmental Protection Agency (EPA) suggests energy efficiency measures could save the US economy $500bn in energy costs over the next 25 years.

The report, entitled the National Action Plan for Energy Efficiency Vision for 2025, sets out a best practice framework for states and utilities seeking to promote energy efficiency measures. It also includes a number of resources to help firms enhance their energy efficiency, including an energy efficiency benefits calculator and a series of best practice guides on assessing and implementing energy efficiency measures.