* China likely to exceed 2015 hydropower targets by 5-10 GW
* Pace of construction falling behind as new approvals slow
By David Stanway
BEIJING, March 10 (Reuters) - China's premier said more hydropower plants would go into construction this year as the country tries to wean itself off polluting fossil fuels and catch up with an ambitious target to raise hydro generation capacity by half before 2020.
China, already the biggest hydropower producer, is on course to exceed a target to raise its hydro capacity by 70 gigawatts (GW) over 2011-2015, but a slowdown in project approvals means it is behind on its longer-term goals.
New capacity approved for construction over 2011-2013 accounted for less than a quarter of the amount originally scheduled in a five-year energy plan published two years ago.
Li Keqiang said in his annual address to the National People's Congress last week that China would start construction on a number of hydro and nuclear power projects this year, with cleaner energy a key part of its new "war against pollution."
Heavy and hazardous smog in major cities has put the government under severe pressure to ease China's dependence on coal. Giant hydropower projects are considered the most effective option, despite the huge costs of resettling migrants and the added risks of earthquakes and ecosystem losses.
China has already built the world's biggest hydropower facility at the Three Gorges on the Yangtze River, with 22.5 gigawatts (GW) of capacity. The third biggest, the Xiluodu project in Sichuan province, will be completed this year.
China said in its five-year plan for 2011-2015 that it would raise total capacity from 220 GW to 290 GW. Capacity had already reached 280 GW by the end of last year, up 12.3 percent from 2012, according to official data.
"Looking at the major projects in the pipeline including those on the Yarlong, Dadu and Jinsha (rivers), which could complete construction by 2015, China would meet and exceed its target ... by as much as 5-10 GW," said Grace Mang, China Program Director with advocacy group International Rivers.
Hydro accounted for about 22 percent of China's total power capacity by the end of last year, with thermal power reaching 862 GW or nearly 70 percent.
CONSTRUCTION FALLING BEHIND
To meet a 2020 target to raise capacity to 420 GW, up 50 percent from the end of last year, the government is committed to putting 120 GW of new plants into construction over the 2011-2015, but tougher approval rules mean it has fallen behind.
"I think hydropower construction will see a relatively large increase this year compared to last year," said Zhang Boting, vice-secretary general of the China Society for Hydropower Engineering. But meeting the five-year construction targets will be difficult, he added.
China has promised to crack down on developers launching construction on big projects before feasibility studies and environmental impact assessments have been passed.
Only 4.82 GW of new hydropower capacity was actually given the go-ahead for construction last year, according to data released by the engineering society last month. Since 2011, only 26.8 GW of new capacity has gone into construction, it said.
While China has started building more plants on major rivers in the southwest, controversial projects on the Nu River in Yunnan and the Brahmaputra River in Tibet are not expected to get the go-ahead in the near term, experts said.
The two projects have been named as possible 2011-2015 building targets, but only one turbine on the Nu is expected to start construction before 2015.
"Looking at it from the current situation, there isn't much chance that those projects will launch construction in the near future," said Zhang. (Editing by Tom Hogue)