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Meltwater won't be good news forever for hydropower
(China Daily)
Updated: 2009-10-27 09:32 Winners and losers The Swiss hydroelectric industry is part-funding Bauder's research, to help it take a long view on new projects in an industry where licenses often run for up to a century. Other risks researchers have identified include sudden floods from swollen glacial lakes. Demand for more pumping technology and dams is one response in countries which can afford them. Experts stress that forecasts so far ahead are highly uncertain, particularly in predicting precipitation, and note that some regions may even benefit. "With climate change, there will be some areas in the world with more precipitation year round," said Petra Doell, a professor of hydrology at the University of Frankfurt and a member of the UN climate panel. "That will mean more hydropower generation even if glaciers melt." For example Norway, which generates almost 100 percent of its power from hydroelectricity, is likely to get more rain and snow because of climate change even as glaciers retreat. But if glaciers do disappear, one main impact will be lower river flows in dry seasons - when irrigation is often needed for crops. That would particularly threaten people in the world's biggest rice-growing region, China and India. Nations with high power demand in dry seasons could suffer from lower flows, but Doell said hydropower reservoirs could be used to mute the overall impacts of melting glaciers downstream. "A reservoir helps to broaden the availability of water throughout the year," she said. "But there are few dams in south-east Asia, where the impacts of melting glaciers will be most severe." Ways to restore water From the Swiss perspective, the Lausanne study forecasts run-off from the Swiss Alps will fall by 7 percent to 2049, as glaciers recede and precipitation rises by 6 percent in winter and drops by 8 percent in summer. These wetter winters and drier summers may force changes in the way Switzerland stores and moves water. In the past, the country used to make sure its storage lakes were full in September to provide hydropower for heating as energy demand peaked in winter, while they were empty in April, ready to be replenished by melting snow and ice. "Since the electricity market was liberalized and listed companies involved, which are more oriented to earning money and delivering energy at the best price, it has been more difficult to fill the lakes in the winter," said Bruno Schaedler, a hydrologist from Bern University. The melting glaciers will be a bonus in the short term, but the hydro industry will have to manage water more efficiently: "When we don't have the reserves of the glaciers, we will need more storage dams," said Joerg Aeberhard, head of hydraulic production at Swiss energy company Alpiq. Swiss hydropower is not completely dependent on glaciers, he stressed: melting snow is more important and provides run-off with less sediment. "We are worried about climate change, but I am more worried as a citizen than as a generator of hydroelectric power." Reuters
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