China spent almost twice as much as the United States on clean energy investments last year, and is now set to take the lead as the world's premier green energy power, according to a report released on Thursday.

In 2009, China invested $34.6 billion on expanding its renewable energy capacity, out of $162 billion invested globally, said a study released by the Pew Charitable Trusts, which measured the growth of clean energy investments in the world's major economies.

The U.S. invested $18.6 billion last year, losing the top spot for most investments for the first time ever. India invested $2.3 billion, ranking tenth among the G-20 group of countries. “There are reasons to be concerned about America's competitive position in the clean energy marketplace. Relative to the size of its economy, the United States' clean energy finance and investments lag behind many of its G-20 partners,” said the report. “The U.S. is on the verge of losing its leadership position in installed renewable energy capacity, with China surging in the last several years to a virtual tie,” it noted.

In the year of the global downturn, China expanded its renewable energy capacity significantly, with its $586 billion stimulus plan devoting an estimated $30 billion to green projects.

China's clean energy investments increased by 50 per cent last year. In the U.S., however, investments fell by 42 per cent.

The report attributed China's success to “ambitious, mandatory targets for wind and solar power and the ample availability of credit.” It blamed an “uncertain” policy framework in the U.S. “with comprehensive legislation stalled in Congress,” for the decline there.

Now, China trails the U.S. by less than 1 GW in terms of overall renewable energy capacity, with 52.5 GW of installed capacity. Of this, 12.2 GW is in wind energy, which has grown rapidly following a government plan to support a fixed-rate feed-in tariff.

The government here has targeted increasing the installed capacity for wind to 30 GW by 2020. India only slightly trails China in this sector, with 11 GW installed. This is forecast to reach 17.6 GW by 2012. The report ranks India fifth overall in terms of installed capacity, with 16.5 GW.

The report found that overall global investment in clean energy fell by only 6.6 per cent last year, in spite of the downturn. It forecasts a 25 per cent growth in the coming year, estimating a $200 billion investment in 2010.