UPDATE 1-German renewable surcharge to rise by 47 pct -source

* Charge to rise to 5.3 cents from 3.6 cents -source

* Network operators all decline to comment

* Increase scheduled to be released on Oct. 15

* Politically sensitive move before next year's election

(Adds details, background)

BERLIN, Oct 10 (Reuters) - Germany's surcharge for renewable energy will rise by 47 percent next year, a government source told Reuters on Wednesday, putting pressure on consumers, who will bear the brunt of costs of the country's energy shift away from nuclear power.

The strong increase reflects the fact that increasing amounts of electricity are generated from renewable sources and that this power is bought from producers at guaranteed prices above market rates.

The so-called 'Umlage' -- charges levied on German consumers to support renewable power -- will rise to 5.3 euro cents per kilowatt hour (kWh) in 2013 from 3.6 cents in 2012, the source said.

The four leading high voltage network operators (TSOs) are scheduled to officially release the increase on Oct. 15.

They include 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.

All four operators declined to comment on the news.

Under German law, green power from sources like wind and solar must be fed into the electricity grid and paid above-market rates in a system partly administered by the TSOs.

The renewable surcharge covers the difference between guaranteed prices paid for renewable energy and market prices for conventional energy.

One year before a federal election in which Chancellor Angela Merkel will seek a third term, the sharp rise in the fee is politically-charged.

German media have made much of the cost to households from Merkel's abrupt decision last year to speed up the switch to renewables and switch off nuclear plants earlier than planned.

Opposition parties have accused the government of letting private consumers bear the brunt of the cost of the shift, not least because it has granted major exemptions to energy-intensive heavy industry.

(Reporting by Berlin bureau, Tom Kaeckenhoff in Duesseldorf and Christoph Steitz in Frankfurt; writing by Christoph Steitz; editing by Keiron Henderson)

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