Last year China overtook the United States in the race to invest in wind, solar and other renewable sources of energy to become the world's biggest investor in clean energy, according to a report published by a US-based think tank.

According to the Pew Charitable Trusts, China's investment and financing for clean energy rose to $34.6 billion in 2009, nearly double the $18.6 billion spent by the US, which ranked second on the list.

The US still dominates venture financing and technology innovation for clean energy, but in manufacturing it lags behind China, which has become a powerhouse in production of both solar cells and wind turbines.

"China has published a series of policies and regulations supporting the development of clean energy during the past five years, which have spurred strong investment into the sector," said Yang Ailun, director of the Climate and Energy Program at Greenpeace.

"Countries with a strong clean energy industry and related technologies will secure an edge in global economic competition in the coming decades," said Yang. "China now holds the opportunity to become a leader in the global clean energy sector."

China has formulated a 10-year program under which clean energy will account for 15 percent of the total consumption mix by 2020, according to Zhang Guobao, head of the National Energy Administration.

To realize the goal, the government will invest billions of yuan in the construction of nuclear power stations, wind farms, solar power plants and research of renewable energy technologies, Zhang said.

Official figures show that renewable energy accounted for 9.9 percent of total energy consumption last year, compared to 8.5 percent in 2008. Amid the global financial crisis, the government has decided to develop renewable energy as part of a stimulus package to keep the economy on the fast track.

For instance, China has led the growth of wind power in 2009 with an astonishing 13,000 megawatts of new wind capacity, the first time any country has built more than 10,000 megawatts in a single year, according to the Chinese Wind Energy Association.

With 25,000 megawatts overall, China has doubled its total installed wind capacity in each of the last five years, bringing it into third place behind the United States and Germany.

Despite a worldwide recession, global clean energy investments reached $162 billion in 2009, and are expected to reach $200 billion this year, according to the Pew report.

It also found that countries with strong nationwide policy frameworks, including renewable energy standards, carbon markets, priority loans for renewable energy projects and mandated clean energy targets, have the most robust clean energy sectors.