Category Archives: shortage

Climate Change Evaporates Part of China's Hydropower

Climate Change Evaporates Part of China’s Hydropower: Scientific American.

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WATER FALL: Unusually low water levels in many Chinese rivers has contributed to a big drop in hydropower production. Image: Tomasz Dunn/Flickr

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.

Although a climate-resilient approach is factored into the designs of hydro projects, China is still likely to suffer from hydroelectric output decline, says Yang. But the nation can seek more clean energy from the sun or wind, which won’t be affected by climate change, and get the electricity generated elsewhere via a smart grid, he said, referring to an advanced transmission infrastructure China has been building.

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.”

Reprinted from Climatewire with permission from Environment & Energy Publishing, LLC. www.eenews.net, 202-628-6500

Heat waves pushes Texas power grid to the limit

Heat waves pushes Texas power grid into red zone | Reuters.

HOUSTON | Thu Aug 4, 2011 4:56pm EDT

(Reuters) – The Texas power grid operator has scrambled this week to meet soaring electricity demand in the face of a brutal heat wave, and residents of the second most populous U.S. state are one power plant shut-down away from rolling blackouts.

Power demand for Electric Reliability Council of Texas, Inc, or ERCOT, which runs the power grid for most of the state, hit three consecutive records this week as Texans cranked up air conditioners to escape one of the hottest summers on record.

The grid operator on Thursday cut power to some big industrial users, and businesses and households face a repeat of the rolling blackouts they faced in February, when a bitter cold snap interrupted power supplies.

Though ERCOT has done a good job balancing supply and demand, “You always have to expect the unexpected can happen,” said Arshad Mansoor, senior vice president at the Electric Power Research Institute (EPRI). “A unit can shut. The wind may not blow.”

It’s been a year of extreme weather for the Lone Star State, already suffering from the worst drought on record.

Ice storms in February crippled dozens of power plants, forcing ERCOT to impose rolling blackouts for hours as electric supplies dropped below demand for the juice.

Now a protracted heat wave with temperatures topping 100 degrees Fahrenheit (37.8 Celsius) for several weeks in a row in many cities has stretched power supplies to the limit.

Power usage in ERCOT reached its highest level ever on Wednesday at 68,294 megawatts, almost 4 percent over last year’s peak.

The Texas grid faces at least one more day of extreme stress before temperatures cool a bit over the weekend. Temperatures in Houston, the state’s biggest city, should return to near normal levels in the upper 90s over the weekend, according to AccuWeather.com.

The state’s biggest power generators, including units of Energy Future Holdings, NRG Energy, Calpine Corp and others, have been running flat out to cash in real-time prices that have hit the $3,000/MWh cap in recent days.

But the state’s reserve margins have been running razor thin. On Wednesday ERCOT came within 50 megawatts of interrupting flows to industrial customers. That’s equal to the output of about 25 industrial-scale windmills.

One megawatt powers about 200 homes in Texas during hot weather when air conditioners are running for long periods.

More generation supplies would come in handy, but state power generators can’t be expected to prepare for every extreme, said Kent Saathoff, ERCOT’s vice president of system planning and operations.

“You have to determine if it is worth spending millions or billions to avoid a one in 10-year event,” Saathoff told reporters on Wednesday.

RECORD BREAKING PRICES

With record-breaking demand came record-breaking prices. Prices for Thursday power topped $400 per megawatt hour, the highest in at least a decade. Friday’s power prices approached $600.

Real-time prices also hit the $3,000 market cap over the past few days.

ERCOT has about 73,000 MW of natural gas, coal, oil, nuclear and wind generating facilities, but not all of that capacity is available all the time.

Texas has the most wind power in the country, but the wind does not blow during the summer. Ercot said it got about 2,000 MW from wind during the peak hour on Wednesday. Those wind farms can produce about 9,000 MW when all turbines are spinning.

Moreover, the ERCOT power grid is a virtual island with only a few small transmission links to neighboring electric grids, making it tough for Texas to pull energy from neighboring states in times of need.

Connecting Texas wires to the rest of the U.S. grid would cost at least as much as a state transmission investment program to carry Texas wind supplies to cities like Dallas and Houston, pegged at about $6 billion, Saathoff said.

(Additional reporting by Scott DiSavino in New York, editing by Chris Baltimore; Editing by David Gregorio)