By Geert De Clercq
PARIS (Reuters) - Renewable energy is far from being able to replace nuclear energy in France's electricity mix, utility EDF's head of nuclear said on Thursday.
Dominique Miniere said a 2015 study by state energy agency ADEME, which showed France could switch to 100 percent renewable energy by 2050 for the same cost as relying on nuclear for half of its power, was not realistic.
"A certain number of points in that study are not based on technological realities," EDF executive committee member Miniere told reporters in reply to a question.
Energy minister Segolene Royal delayed publication of the controversial study until after parliament voted last summer for the energy transition law, which pledged more support for renewables but maintained reliance on the atom for about three quarters of French electricity.
"We do not believe in a 100 percent renewables mix by the horizon (ADEME) indicates. However, we want to extend the lifespan of our reactors in order to allow a gradual increase of renewables in the mix," Miniere added.
He said replacing nuclear with renewables too quickly, citing Germany as an example, ends up boosting carbon emissions from fossil fuel.
He said Germany's 80 gigawatt installed renewable energy capacity is about 1.3 times installed French nuclear capacity, but produces three to four times less power per year because solar and wind operate only about 15 percent of the time compared to about 80 percent for nuclear.
Miniere said that in 2010 French power production emitted 10 times less carbon than Germany's, but that as Germany has switched on more coal and lignite plants to compensate for closed nuclear reactors, France now emits 30 times less carbon.
Miniere - whose name was not on a letter of EDF engineers supporting EDF's project to build nuclear reactors in Hinkley Point, UK - denied he did not back the project.
He said the letter was signed by staff who had worked on Hinkley Point or EDF's new nuclear plant in Flamanville, France.
"These people had the credibility to sign," he said, adding there was no internal opposition between managers of the existing fleet and managers in charge of new nuclear projects.
EDF's unions and some of its senior staff want the company to delay Hinkley Point by several years in order to avoid further stretching EDF's balance sheet.
(Reporting by Geert De Clercq; Editing by Ruth Pitchford)