US carbon emissions have fallen 13 per cent over the past five years to reach their lowest levels since 1994, according to a new report published by Bloomberg New Energy Finance on behalf of industry group the Business Council for Sustainable Energy (BCSE).
A doubling of renewable energy capacity and increases in the use of natural gas have reduced reliance on coal and oil, while improving energy efficiency has seen demand for energy fall steeply.
Renewables represented the largest single source of new growth last year.
Costs are also falling: large solar power plants produced electricity at an average of 14 cents per kilowatt hour in 2012, compared to 31 cents/kWh three years beforehand.
In contrast, from 2007 to 2011 coal's share of the energy mix declined from 22.5 per cent to 18.1 per cent and oil fell to 36.7 per cent from 39.3 per cent.
Meanwhile, energy demand decreased by 6.4 per cent from 2007 to 2012 largely due to efficiency gains and despite economic growth.
The report notes energy efficiency is increasingly becoming a business priority, particularly among large power consumers such as manufacturers. US utility budgets for efficiency expenditures reached $7bn in 2011, while the energy intensity of commercial buildings has fallen by more than 40 per cent since 1980.
Emissions cuts also came in the transport sector, where sales of hybrids and plug-in vehicles reached 488,000 units in 2012.