“And in Germany (for years) we have been acting as if the question of adding secured power is something that can be postponed. We can already see very clearly today what happens when power is switched off and no backup is provided for renewables.”
Markus Krebber, CEO RWE AG
On November 6, the price of power rose to €800 MWh because of a 12-day wind drought. That’s Markus Krebber, CEO of the German multinational energy company RWE AG RWE.78%, writing an open letter about the state of Germany’s energy sector.
In early November, a 12 day weather event called a “Dunkelflaute” made it impossible for wind farms to work in the UK, Germany, and other northern European countries. This is also called a “dark wind lull,” and it happens when the wind speeds drop so low that windmills can’t make much power.
It meant that wind farms could only meet 3-4% of the U.K.’s energy needs during the morning and evening peaks on November 5. Instead, gas-fired plants had to be turned on to meet about 60% of demand. Grid openness data shows that the rest was made up of power from nuclear and biomass plants, solar farms, and imports through interconnectors.
The same thing happened in Germany, where wind farms only produced 7% of their capacity because the wind speed was so low. The Telegraph newspaper says that 31% of the morning’s power needs were met by warming up coal-fired power plants. Natural gas provided 18% of the power, and solar farms provided 12%.
It’s static high-pressure systems that cause “dunkelflautes.” These systems cover large areas and make the winds and weather cloudy and weaker than usual.
Complete drops in wind generation are very rare, but sharp drops in output are a known problem and one of the main issues grid planners are trying to solve as they switch to renewables that depend on the weather.
China and Germany both use fossil fuels and renewable energy to make power. Wind and coal are the main sources of electricity in China. Germany gets three times as much power from wind and sun as the rest of the world combined. The country has also been a leader in offshore wind and solar power production.
