A windfarm in China – a new report by Pew said the country has overtaken the US as the top clean technology investor. Photograph: Keren Su/Getty Images/China Span RM

China has overtaken the US for the first time in a league table of investments in low-carbon energy among the G-20, according to a new report by not for profit group the Pew Charitable Trusts published this week.

The report found that despite an overall 6.6 per cent global decline in clean energy investments last year, China invested almost twice as much as the United States in clean energy during 2009.

Pew blamed the worst financial downturn in over half a century for the reduction in clean techinvestments, but echoed growing confidence in the sector, predicting investments will bounce nback to around $200bn this year.

The report, entitled Who’s Winning the Clean Energy Race?, said that last year China invested $34.6bn in the clean energy economy, placing it top of the clean energy investment league and well ahead of the US in second place with investment of $18.6bn.

Phyllis Cuttino, director of Pew Environment Group’s US Global Warming Campaign, criticised the US government for failing to deliver stronger national policies to support renewable energy. “I’m worried that we are going to fall further down the list next year,” she said. “We really need to pass policy.”

The US administration has been locked in a year long battle to pass a climate change bill that would impose a national carbon pricing mechanism and introduce new incentives for low carbon projects. However, the bill has faced staunch opposition from Republicans and some Democrats and while a compromise version of the legislation is expected to be unveiled in the next few weeks commentators remain sceptical that the bill can pass this year.

The Pew report also expressed concern about America’s competitive position in the clean energy marketplace, noting that relative to the size of its economy the US clean energy finance and investments lag behind many of its G20 partners.

In relative terms, the UK invested three times more than the United States last year, and overall 10 other G20 members devoted a greater percentage of gross domestic product to clean energy than the United States in 2009.

The Pew report said those countries with strong, national policies aimed at reducing global warming and encouraging the use of renewable energy – including the UK, Germany and Spain – had succeeded in establishing stronger competitive positions in the clean energy economy.

“Nations seeking to compete effectively for clean energy jobs and manufacturing would do well to evaluate the array of policy mechanisms that can be employed to stimulate clean energy investment,” the report stated. “This is especially true for policymakers in the United States, which is at risk of falling further behind its G20 competitors in the coming years absent adoption of a strong national policy framework to spur more robust clean energy investment.”