BERLIN An uncontrolled renewable power expansion in Germany could threaten the stability of energy grids, the head of energy agency Dena told Reuters on Wednesday.
Failure to connect new capacity near demand centers or near transport grids or storage facilities would waste assets or put at risk the grids' stability, said Dena's director, Stephan Kohler, in an interview on the sidelines of a sector conference.
"My demands for the new renewable energy laws would be that additional capacity is to be built only where there is an existing network infrastructure," he said.
"Another prerequisite would be that it must be possible to absorb the new capacity through demand side management or integrate it in storage systems at a European level," he added.
Dena assumed in 2007 studies that an additional 45,000 megawatts (MW) of new German wind power would be added by 2020.
But thanks to generous subsidies -- to be enhanced by Germany's shift entirely away from nuclear -- there has been runaway growth of both wind and solar power.
Dena has now learned that two northern and the eastern German states alone plan on adding possibly 50,000 MW of onshore wind power and 8,000-10,000 MW of offshore by the year 2020, he said.
"In other words, we stand to get 60,000 MW of power capacity where the power is not consumed," Kohler said.
These regions are sparsely populated, unlike Germany's south, the home of most energy-intensive industry.
"We could get an economic problem because we would have to switch off turbines in a storm because we can't transport the power...that would be both costly and unintelligent," he said.
MISSION NOT IMPOSSIBLE
Similarly, solar power expansion is due to cost taxpayers and power consumers dearly, and to bring engineering problems.
The government assumes that operators will add 2,000-3,000 MW to the existing 18,000 MW of capacity by the end of the year, but Dena, which is half controlled by Berlin ministries and half by financial institutions, expects growth by 3,000-4,000 MW.
Kohler said that power inverters to avoid a simultaneous switch-off on overly sunny days will have to be refitted.
Capacity drops must be cascaded so as not to stress the system, or cause overusage of expensive balancing power.
Kohler said he did not want to be alarmist. Dena was trying to suggest viable solutions and supported the government goals.
"The strategy change can work when there is an acceptance and if the population participates actively,...we have to take people along," he said.
Dena is lobbying for acceptance for high voltage grid expansions by 3,700 kilometers by 2025 of which it thinks 850 km could be realized by 2015, if more efficient laws are passed.
Citizens would have to do their part -- buying new gadgets, home insulation and smart meters, to assist the transition.
Dena believes that power cost hikes for householders arising from the disappearance of nuclear power, grid expansions and renewable subsidies can be limited to 20 percent up to 2020.
(Reporting by Vera Eckert)