100% renewable energy sources require overcapacity (Vol. 48 No. 2)

Germany's greenhouse gas (GHG) emissions from 2002 to 2015 and the political target for 2020 (bars)

To switch electricity supply from nuclear to wind and solar power is not so simple

Germany decided to go nuclear-free by 2022. A CO2 -emission- free electricity supply system based on intermittent sources, such as wind and solar — or photovoltaic (PV) — power could replace nuclear power. However, these sources depend on the weather conditions. In a new study published recently, the author analysed weather conditions using 2010, 2012, 2013 and 2015 data derived from the electricity supply system itself, instead of relying on meteorological data. By scaling existing data up to a 100% supply from intermittent renewable energy sources, the author demonstrates that an average 325 GW wind and PV power are required to meet the 100% renewable energy target. This study shows the complexity of replacing the present primary energy supply with electricity from intermittent renewable sources, which would inevitably need to be supplemented by other forms of CO2 - free energy production.

F. Wagner, Surplus from and storage of electricity generated by intermittent sources, Eur. Phys. J. Plus 131, 445 (2016)