First published in the New Scientist, 7 July 2011.
Chancellor Angela Merkel’s government claimed to be “ushering in the age of renewables” as German MPs passed legislation this week to phase out nuclear power by 2022 – but the basic arithmetic of the energy-switch policy suggests the country will struggle to fill the hole left by nuclear power – and emissions may rise in the interim.
The vote means that by early next decade Germany will lose 20 gigawatts of nuclear power, which supplied the country with 23 per cent of its electricity last year. Renewables supplied Germany with 17 per cent of its electricity in 2010, so the country generated 40 per cent of its electricity from zero-carbon sources.
Under existing targets, which pre-date the nuclear U-turn, the government plans to double renewable electricity to 35 per cent by 2020. In fact, in its Renewable Energy Action Plan submitted to the European Commission last year, Germany projected that renewables could deliver almost 39 per cent by that date. That was on the basis that gains in energy efficiency would cut demand by almost 9 per cent, which may not be achievable in a growing economy.
Either way, it seems unlikely that electricity from renewables alone can completely replace the 40 per cent of electricity now generated from a combination of nuclear and renewables before the last nuclear station closes. That’s because renewables require far more generating capacity than the technology it replaces as wind and solar are intermittent.
Germany will plug the gap by building coal and gas-fired power plants with a combined capacity of 20 gigawatts for cloudy or windless days. Opposition to carbon capture and storage in Germany – where the technology is seen as an excuse to justify continued reliance on coal – means the carbon emissions from these plants may not be collected.
So it looks as if the country will at best have about the same level of zero-carbon generation in 2020 as today – 40 per cent – and that emissions will rise in the interim.
Had Germany been prepared to retain its nuclear capacity and achieved its renewables target, the zero-carbon share could have risen to 58 per cent.