Melting glaciers offer hydro benefit to Switzerland

Glaciers, as they melt, are creating new lakes in the Swiss Alps

Zinal Glacier in the Val d'Anniviers, at sunset 13 September: as the light of day fades, the glacier's melt lines become more apparent - to view full size:

BERN / LAUSANNE, SWITZERLAND – The heart-rending story of the disappearing Alpine glaciers, with some estimates saying they will be gone by the end of this century, may be hiding a promise that will help Switzerland as it moves away from nuclear energy. A graduate student at EPFL in Lausanne has been investigating the options offered by new lakes created by the glaciers as they disappear.

Anton Schleiss, director of EPFL’s Hydraulic Constructions Laboratory, is participating in the project. “Glaciers store water and transfer winter precipitation into summer runoff. Once they have disappeared, we will need to manage these new reservoirs, which will take over this water storage role.”

Switzerland’s commitment in 2011 to close its nuclear power plants by 2050 relies heavily on the country’s ability to use current and potential hydroelectric sources, EPFL states in a press release.

Civil Engineering student David Zumofen studied several options for how Switzerland can take advantage of new natural reservoirs to produce electricity.

EPFL, in a press release, describes the options:

“In the first scenario, the lake water would go through turbines on site, as part of the construction of a future Gletsch-Oberwald hydroelectric power plant. This would yield less energy, but would not require altering any existing structures between the Rhone and Lake Geneva.

“The second scenario would use the existing hydroelectric structures in place in Oberhasli, on the other side of the Grimsel Pass, at the drainage divide between the Rhine and Rhone watersheds. Because the water can pass through existing turbines several times on its journey downstream, this solution is much cheaper and could generate more electricity. The only problem is that the water will end up in the Rhine, depriving the Rhone of an important source of water.”

The Rhone glacier is one such potential source. It has been retreating rapidly for over 100 years, and in the past 10 years it has lost 6 percent of its mass, according to the research project on the risks and possibilities of these new mountain lakes, funded by The Swiss National Science Foundation.

“Today, its tongue has retreated far up the watershed. From previous studies we know that two large cavities, each more than 50 meters deep, are hidden beneath the glacier. One of them may be completely uncovered by 2065, creating a lake that could be used for generating hydroelectric power.

“‘We must be careful about making climate predictions, because what was true a century ago may well no longer hold 100 years from now,’ says Zumofen. ‘If current predictions are correct, however, one of the two lakes could hold up to 50 million cubic meters of water.’ Zumofen analyzed the outflow of the glacier both during melting and once the glacier is completely gone, confirming the advantage of exploiting the lake, which will remain large even when the glacier no longer exists.”