Can supply be secure with so much electricity provided by wind and solar energy?
Germans can count on a continued reliable supply of electricity in the future. The country’s energy supply is one of the best in the world. Over the 8,760 hours in a year, its supply is down for an average of only 12 minutes. Indeed, power cuts have been reduced even further in recent years, despite the increasing amount of electricity generated by wind and solar energy.
Power cuts are very rare in Germany
Average length of power cuts in minutes in 2013
Power cuts are rarely caused by fluctuations in electricity generation. They mainly result from external factors or human error. This was also the case during the last major blackout in parts of Germany on 4 November 2006. This power cut, which lasted for around two hours, was caused by a planned routine disconnection of a power line. This overloaded other power lines and led to a chain reaction in the European grid. Since this incident, the security mechanisms in Germany and neighbouring European countries have been improved even further.
For example, Germany has set up a fixed reserve of additional power plants in order to prevent shortfalls. These plants are particularly important during the winter months when consumption is especially high and German wind turbines are at their most productive. If the power grids are overloaded because they are transporting large amounts of electricity from northern to southern Germany, these back-up plants cover demand in the south.
How does generation by renewable energies fluctuate?
Power generation by all sources of energy and power consumption in Germany over the course of 2014
Renewable energy already provides over 60 percent of Germany’s electricity supply at certain times, and this share will continue to increase in the coming years. The various renewable sources complement each other. Pilot projects have shown that it is possible to combine power generation from the various types of plants, thus enabling them to provide a far more reliable supply of electricity. At times when there is no sunshine or wind, flexible conventional power plants bridge the gap. Gas power plants work particularly well in such cases, but pumped storage plants and bioenergy plants are also able to provide electricity quickly. However, the plan is that storage systems will bridge the gap during such periods in the future.
Electricity consumers also play an important role. They can be given incentives to use electricity when supply is high, such as times of high winds. Large-scale consumers – factories or cold storage warehouses, for example – can significantly reduce the burden on the overall system in this way.
The great challenge is to restructure the electricity market. Flexibility is important. All actors in the electricity market must react as well as possible to the fluctuations in the electricity generated by wind and solar energy. At the same time, there must be competition between the various balancing options in order to keep the overall costs low.
Transnational grid expansion and the integration of what were previously separate regional electricity markets in Europe are also bringing about greater stability and flexibility in Germany.