China and Japan stepped up spending last year in renewable energy but overall global investment declined due to economic and policy uncertainties in the West, a study said Wednesday.

The annual report by the Pew Charitable Trusts found that China reclaimed from the United States its place as the nation with the most clean energy investment, which climbed 20 percent from a year before to $65.1 billion.

But worldwide investment declined 11 percent last year because of factors including economic woes in Europe, political sensitivities about energy prices in Germany and uncertainty over the extension of a tax credit in the United States, it said.

At the same time, the clean energy industry installed a record 88 gigawatts in capacity last year as prices for the technology declined.

"That's the interesting thing -- we had an investment decline but we still had more gigawatts installed than we ever had," said Phyllis Cuttino, director of the clean energy program at the Pew Charitable Trusts.

"So the investment dollar is going further and that's particularly true with solar," she said.

For the second consecutive year, solar topped wind energy in investment as costs due to rapid declines in price.

But the lower prices, coupled with US and European charges of unfair Chinese government support, has also caused havoc for some solar companies. China's Suntech, once the world's largest solar panel producer, filed for bankruptcy last month.

The report said clean energy production in Japan rose by 75 percent last year as the government encouraged solar energy following the Fukushima nuclear disaster following the March 2011 earthquake.

An earlier Japanese government set a goal of moving away from nuclear power, but Prime Minister Shinzo Abe, whose conservative Liberal Democratic Party won December elections, supports nuclear energy.

Clean energy investment by South Korea rose by 50 percent, although the total level remained near the bottom among Group of 20 economies.

Investment in clean energy also cooled in India and fell sharply in Indonesia, where the government put its focus on geothermal power.