Climate Change Evaporates Part of China's Hydropower

The nation's hydropower production dropped by 25 percent thanks to an unusual drop in river flow

Nov. 8, 2011 - Coco Liu and ClimateWire - scientificamerican.com

SHANGHAI -- China has set ambitious goals for itself to develop hydropower to help mitigate the risks of climate change, but increasing extreme weather events likely rooted in climate change are now sabotaging the goals' foundations.

The latest blow came in September, when many major rivers across China ran into an unusual shrinkage, with less than 20 percent water remaining at some stretches. As a result, the nation's hydroelectric generation dropped by almost a quarter compared with last year. There has been an ever-widening decrease in power each month since July, according to a recent government statement.

As water stocks in key hydro stations decline, the regular dry season is approaching. The resulting stress on hydroelectric generation will last into next year, the statement said.

The Chinese government has yet to explain why the water flows slumped. But experts blamed it on climate change, warning of more future droughts in areas traditionally blessed with water.

If this expectation comes true, it will hamper China's hydropower sector, which contributes most of the country's carbon-free electricity. It will also threaten a national strategy in transmitting electricity from resource-rich western China to feed the country's power-hungry manufacturing sector, most of which is in the east.

For Guangdong province, located on China's east coast, this threat has already turned into a daily reality. Since its western neighbors this year failed to send as much electricity as usual, the manufacturing hub, with a capacity to produce more than half of the world's desktops and toys, is forced to conserve electricity.

Turbines left high and dry
China Southern Power Grid, the region's electricity distributor, attributed the energy shortage partly to the evaporation of hydropower.

As of July, on average, not even half of its installed hydropower capacity found water to turn turbines, the company's statistics show. And several major hydro stations, built as part of the west-to-east electricity transmission plan, failed to do their jobs.

Goupitan, the largest hydroelectric generator in Guizhou province, reportedly produced only 10 percent of its normal output per day, due to shrinking water flows. And in another hydro station called Longtan, located in the Guangxi region, this year's missing rain dropped its reservoir's water level to a point dozens of meters lower than previous years.

"This will definitely negatively affect our hydroelectric production from now to next summer," said Li Yanguang, who is in charge of public relations in the power station. Asked whether next summer -- a regular rainy season -- could make the situation better, Li answered in a cautious tone.

"This totally depends on weather," he said. "We can't predict that."

Hydro growth plan sticks despite falling power output
But Lin Boqiang, one of China's leading energy experts, is confident that the nation's hydroelectric generation may just go in one direction: getting worse.

"If climate change caused this year's water flow decreases, which I think it did, and then its impact [on rivers] will be a long term. It will take a toll on China's hydroelectric output, and also push up the cost of using it," explained Lin, who directs the China Center for Energy Economics Research at Xiamen University.

But still, from Lin's point of view, such setbacks can't compete with the Chinese desire for tapping more water power. China, already the world's largest hydropower user, plans to add another 120 gigawatts by 2015 -- a crucial step toward greening 15 percent of its power mix by the end of the decade.

Yang Fuqiang, a senior climate and energy expert at the Natural Resources Defense Council, agreed that China's hydropower plan will stand, though not primarily for energy supply concerns.

So what's the point of keeping hydro?

"In the future, the importance of hydro projects won't be on power generation, but on water management," Yang explained. "It helps control floods, ensure ships transportation and reserve water -- a function that [water-scarce] China needs badly."