Germany's environment minister raised eyebrows on Sunday by conceding that some of the targets that are part of the government's policy of phasing out the use of nuclear energy, while at the same time cutting emissions of greenhouse gases, may not be achievable.

"It has to be questioned whether we'll really succeed in reducing electricity use by 10 per cent by 2020," Peter Altmaier said in an interview with the Bild am Sonntag newspaper.

"If we are going to somehow achieve this, it will take tremendous effort, " he said.

Altmaier also admitted that the government had a long way to go in efforts to convince a large number of Germans to switch from vehicles powered by internal combustion engines to electric cars.

They're may be "significantly fewer" electric cars on the road by 2020 than the government had previously assumed, the minister said.

Chancellor Angela Merkel's center-right coalition had previously said that it was on track to put a million electric cars on the road by 2020. Official figures put that number at just over 4,500 at the start of 2012.

Rising consumer costs a possibility

Altmaier also warned of the danger of rising energy costs for consumers.

"If we aren't careful, the energy reforms could develop into a social problem," he said, admitting that in efforts to replace nuclear energy with renewables, "the question of energy affordability had been overlooked."

He also said that turning off a number of nuclear plants meant that power shortages could not be ruled out in the coming winter.

"Last winter there were a few critical moments, which we have learned from," he said, adding that preparations were underway to ensure this doesn't happened again.

Opposition criticism

The opposition Social Democrats (SPD) were quick to seize on Altmaier's words.

"He's admitting the government's energy overhaul has utterly failed," SPD chairman Sigmar Gabriel said.

Altmaier, who only took up the post this past May, after Chancellor Merkel sacked his predecessor, Norbert Röttgen, admitted that mistakes had been made in the past. He added that he would be judged as environment minister on how successful he was in putting this right.

Chancellor Merkel's government decision to phase out the use of nuclear energy by 2022 followed the partial meltdowns of nuclear reactors at Fukushima in Japan last year.

pfd/msh (dpa, AFP)