German power grids increasingly strained by solar and wind generation
By Paul-Frederik Bach
30 May 2012 With a steep growth of power generation from photovoltaic (PV) and wind power and with 8 GW base load capacity suddenly taken out of service the situation in Germany has developed into a nightmare for system operators. The peak demand in Germany is about 80 GW. The variations of wind and PV generation create situations which require long distance transport of huge amounts of power. The grid capacity is far from sufficient for these transports. The result is a remarkably large number of curtailments of RES (Renewable Energy Sources). Reports from the European Network of Transmission System Operators for Electricity (ENTSO-E)[1] and the German Grid Agency[2] reflect concern for the operational security of the power system. The risk of a prolonged and widespread power blackout was earlier recognized by the German Bundestag and discussed in an interesting report[3]. This note will present main conclusions from the three reports combined with data, collected from the German system operators. Since January 2012, all 4 German system operators have published estimated PV generation based on representative samples. The data will give research environments a new opportunity to analyse the impact of RES in Germany. Some observations are possible […]:
- Wind power peaks seem not to be simultaneous with PV peaks. This means that PV does not add its full peak capacity to the grid problems during high wind periods.
- The main part of the German wind power is installed in the northern part of the country while the main part of the PV capacity is installed in Bavaria. The nuclear moratorium has created the most serious supply problems in the southern part of Germany. This observation suggests additional PV generation to relieve the supply problems.
- PV generation cannot reduce the need for peak capacity. The reason is that there is no PV generation during the evening peak load.
- The regulating work which must be made by controllable power sources grows considerably with the growth of wind power and PV. TenneT is one of Germany’s 4 main grid operators. In the TenneT area a calculation for April 2011 has shown that wind power alone would extend the regulating range by more than 50%, while the actual combination of wind power and PV has doubled the regulating range. […]
