Subsidies levied on German consumers to support renewable power will rise by 47% next year, putting pressure on Chancellor Angela Merkel's ruling coalition to keep energy costs in check ahead of a federal election next year.

Merkel's decision to abandon nuclear power following last year's Fukushima disaster has led to a growing need for alternative energy sources, causing higher charges that are tagged on to consumers' energy bills.

Germany's surcharge for renewable energy will rise to 5.3 cents per kilowatt hour (kWh) in 2013 from 3.6 cents in 2012, Germany's four leading high voltage network operators said on Monday, confirming a Reuters report from last week.

Overall, the so-called 'Umlage' will reach €20.36 billion ($26.40 billion) next year, the operators said.

"It is clear that companies can't compensate the strong increase in the regulated component of power prices and are forced to pass it on to customers," said Hildegard Mueller, head of energy industry association BDEW in a statement.

Germany's No.2 utility RWE said it would keep electricity prices stable at least until early 2013 for about 1.5 million of its customers. A spokesman for E.ON, the country's largest utility, could not say when and to what extent it would pass on higher costs to customers.

Coming a year ahead of a federal election in which Merkel will seek a third term, the sharp rise in the surcharge has become a major issue, potentially forcing the government to find ways to limit costs for consumers.

It has also opened divisions in the coalition with the Free Democrats (FDP), junior partners to Merkel's conservatives, calling for steeper cuts in government-mandated incentives and a more sweeping reform of the renewable energy law (EEG).

Opposition parties have accused the government of letting private consumers bear the brunt, after it exempted energy-intensive heavy industry from green energy and network usage tariffs.

Representatives for Germany's steel and chemicals associations warned of higher energy costs for their sectors, calling for a review of Germany's renewable energy act.

Germany's four network operators are 50Hertz, owned by Belgian Elia and Australian fund IFM; E.ON's former high voltage grid unit TenneT ; RWE's former unit Amprion, and EnBW's grid unit TransnetBW.