FRANKFURT, Nov 19 (Reuters) - German transmission network operators (TSOs) have been calling on additional power capacity reserves after storm winds have been too strong for some wind turbines, forcing them to switch off.
The use of reserves for the past 11 days was to keep grids stable and was expected to be complete by Nov. 20, the TSOs said on Thursday.
Electricity demand in Europe’s biggest market is high and erratic renewable supply requires a backup in the winter months, for which the four TSOs have signed up a total 7,500 megawatts (MW) of additional capacity for the 2015/16 winter season.
Wind volumes of late have been running at 30,000 megawatts (MW) on a daily level, compared with installed wind capacity of nearly 40,000 MW.
“Based on wind feed-in forecasts, we have been calling on 200 to 2,200 MW (additional capacity) daily,” said the TSOs that are supervised by Germany’s energy regulator, in a joint statement.
The scheme under which designated generators hold spare capacity for short-term use is funded by consumers.
It became necessary from 2011 onwards, when Germany shut 40 percent of its nuclear power capacity following the Fukushima disaster.
Since then, utilities have also been closing coal and gas-fired plants, due to competition from fast-growing renewables.
Another problem is that power network expansion between the north and south has been too slow, which poses the risk of shortages for heavily consuming southern industries while most German wind power is located in the gusty North.
“Although the security of supply is not acutely endangered, the risk potential for power grids and supply...has risen significantly,” the TSOs said.
They are utility EnBW’s TransnetBW, 50Hertz, the former grid unit of Vattenfall Europe, TenneT, formerly part of E.ON, and Amprion, previously owned by RWE. (Reporting by Vera Eckert, editing by William Hardy)