China will expand its installed hydropower capacity to 300 million kilowatts by 2015 from the current 200 million in an effort to cut carbon dioxide emissions, the country's top energy official said Wednesday.

Zhang Guobao, director of the National Energy Administration (NEA), told the popular web port Sina.com in an on-line interview that such an expansion is needed for China's goal to reduce its carbon dioxide emissions per unit of gross domestic product (GDP) by 40 to 45 percent by 2020.

China promised at the Copenhagen Conference on global climate change last year that it would generate 15 percent of its power from non-fossil sources by 2020, up from the current 7.8 percent.

"We will take the initiative to deliver that promise even though the task is not easy at all," Zhang said. "But we still have a lot of basic work to do."

China has long relied on coal to fuel its economic growth as about 83 percent of its electricity output is produced by coal-fired power stations.

China's non-fossil sources-generated energy include hydropower projects, nuclear power stations, wind power and solar plants, with hydropower accounting for about three fifths of the total.

Zhang said China would step up its efforts to develop hydropower projects across the country under stricter approval procedures, which focus on the protection of the environment, rights of relocated immigrants and land resources.

Of China's 542 million kilowatts of exploitable hydroelectric potential, only 400 million kWh is suitable for hydropower construction, Zhang said.

"So China can only develop a maximum of 400 million kWh of installed hydropower capacity," Zhang said. "The final hydropower generation would likely be between 300 million and 350 million kWh."

Zhang said the NEA is still studying the feasibility of raising the on-grid price for hydropower to the same rate as electricity produced by thermal power plants.

Such proposal, if adopted, would benefit hydropower operators but increase costs for grid operators and the public.

"Views on raising the on-grid price for hydropower vary among different government departments, and the public at large," Zhang said. "We should take into account what society can afford."

China's feed-in tariff for hydropower projects is mostly between 0.2 yuan and 0.3 yuan per kWh, but the rate for coal-fired power plants ranges higher between 0.3 and 0.4 yuan per kWh. Feed-in rates for wind and solar power are even higher.

China maintains rigid price controls on energy resources including power, gas and oil. On-grid power prices often vary by plant and retail rates differ between region, industry and even users.

Any electricity rate hike must be approved by the National Development and Reform Commission, China's top economic planner. Zhang himself is also deputy director of the commission.