ESSEN, Germany, Feb 6 (Reuters) - Germany's power grids have coped with the coldest winter in Europe since 2012, though they have had to turn to costly back-up supplies more frequently than last winter, the country's energy regulator said on Monday.
The Bundesnetzagentur said there had been 68 days so far this winter when back-up supplies were needed to balance the network, compared with 47 days for the whole of the October-March period in 2015-16.
"There have been significantly more network balancing efforts than last winter," said Jochen Homann, president of the Bundesnetzagentur authority which oversees grid system operators.
"But we seem to have mastered the most difficult winter period," he told Reuters during a conference.
Power market operators and traders have been concerned about possible capacity shortages in the interconnected western European region where nuclear-reliant France has been struggling to keep up sufficient supplies amid increased reactor downtimes.
This poses challenges because power cannot be stored and reserves need to be activated rapidly if there are regional shortfalls.
Germany is Europe's default power exporter because it has built up surplus capacity due to its rapid expansion of renewable power generation.
The Bundesnetzagentur has signed up providers of 5.4 gigawatts (GW) of winter reserve capacity from Germany, Italy, Switzerland and Austria for the six month period.
This additional generation capacity, which is coal-, gas- and oil-fired, can be called upon on during shortages.
The cost of these supplies is added to grid fees, which are shared by consumers as part of their final bills.
A maximum of 3.4 GW has been called upon on any one occasion this winter, showing provisions had proven adequate, Homann said.
The Bundesnetzagentur has said 216 million euros ($232 million) were spent on coping with winter demand in 2015/16.
In the fourth quarter of last year, France saw its lowest nuclear power availability in 10 years, 5 GW below the previous winter. The country traditionally relies on a high percentage of electric heating.
French supply has been rising in early 2017, but a new cold weather period is on its way this week.
Homann said the Bundesnetzagentur and French peer RTE were in close contact, should the need arise to tackle network problems jointly.
$1 = 0.9318 euros Reporting by Vera Eckert; Editing by Mark Potter