Germany's water balance benefits from renewables expansion, fewer thermal plants – UBA

Germany's renewable power expansion, the finalised phase out of nuclear, and the ongoing decommissioning of coal and gas power plants have had a positive effect on the country's water balance, both in terms of water quantity and temperature, a report by the Federal Environment Agency (UBA) has found. The energy industry has historically withdrawn significant amounts of water for use as a cooling agent for conventional power plants and discharged heated water back into rivers in return. In recent years, however, a decline in water withdrawal quantities has been observed, UBA noted.

"The more consistently and rapidly the complete phase-out of the use of fossil fuels for energy applications is carried out and accompanied by an ambitious expansion of renewable energies, the faster the negative impacts of cooling water use on the water balance will be reduced," the report said.

The authors noted, however, that there is currently little reliable data on the water demand for the operation of renewable energy technologies, so it was not possible to determine how much water their operation requires. Wind turbines and solar panels need water for cleaning purposes but it was not clear how often this happens or how much water is needed. With bioenergy, water is needed to irrigate energy crops but, again, there are no official statistics to quantify water demand, the authors noted. Future water demand for geothermal energy generation would depend on which cooling technology prevailed as well as on the installed capacity.

While the water demand of renewable energy is hard to estimate, it is expected to be significantly lower than water withdrawals from thermal power plants, the authors concluded. "In order to preserve the positive effects of energy system transformation on the water balance, the influence on the water balance of alternative forms of energy and storage must be examined," they wrote.

Ground water levels in Germany are under stress from a range of factors, including longer dry spells caused by global warming and local withdrawal for energy generation purposes, which in the region surrounding Germany's capital Berlin has led to calls for increasing water prices to curb industry demand. With a national ‘Water Strategy’, Germany's government has aimed to improve the resilience of the country’s water supply.