China's increase in renewable energy is on course to surpass the European Union, the United States and Japan combined, says the International Energy Agency.

In its annual World Energy Outlook released Tuesday, the IEA said China will be the strongest driver in the worldwide trend in which renewable energy is expected to account for almost half of the increase in global power generation by 2035, China Daily reports.

China's 12th five-year plan, covering 2011-2015, calls for 30 percent of electricity to come from non-fossil fuels by 2015, up from 5 percent in 2001. By 2015, China also aims to cut its energy consumption per unit of gross domestic product by 16 percent and CO2 emissions per unit of GDP by 17 percent.

China is the world's largest emitter of greenhouse gases.

Fatih Birol, the IEA's chief economist, said in an interview with China Daily, "The good news for China playing an active role in developing renewable energy is that it will help decarbonize the global energy system."

The IEA report comes as delegates from some 190 countries attend the United Nations climate conference in Warsaw, Poland, which aims to lay the groundwork for a new global climate pact that sets post-2020 targets on emission cuts.

"The main challenge for global renewable energy today is that it is costly. If China builds a lot of renewable energy projects, it will help bring down the cost and enable it to compete with traditional sources of energy, namely coal and gas," Birol told the newspaper.

China, the world's biggest consumer of coal, has accounted for 82 percent of the increase in global coal consumption since 2011, the U.S. Energy Information Administration says.

Last year, coal accounted for around 67 percent of China's energy mix, but the dirty fossil fuel has been blamed for the country's massive air pollution.

As part of a plan released in September by China's State Council, or cabinet, the government aims to cut total coal consumption to below 65 percent of its total primary energy use by 2017.

In the China Daily report published Wednesday, Birol noted that China's decision to put a cap on coal consumption will also boost the country's natural gas market.

"The challenge is that the price of natural gas is much more expensive so it is a critical task for the policymakers to find a balance between consuming less of the dirty fuel and dealing with the increasing cost of economic development," he said.