Prices for electricity in Germany have dipped below zero more than 100 times this year alone, according to EPEX Spot. Customers are being paid to consume power which is the result of low demand, unseasonably warm weather and strong breezes that provided an abundance of wind power on the grid.
This Sunday, factory owners and other major consumers were at times paid more than 50 euros, about $60, per megawatt-hour, a wholesale measure, to consume power off the grid. Negative prices are not the norm in Germany but recently they have become less rare due to high investments in green technologies throughout the country.
Demand is particularly low on weekends and holidays, when factories are idle and offices empty. The energy supplies that Germany depends on, however, are less predictable than they used to be.
Particularly interesting is the wind-energy infrastructure, the output of which is highly dependent on changes in weather and is very unpredictable. Giant spinning turbines produce, on average, about 12 percent of Germany’s power, but on windy days, they can generate several times more.
Other main sources of the country’s electricity supply, especially some coal and nuclear power plants, are unable to dial back quickly enough, which results in negative prices on the market.
The major drawback of both wind and solar power is that they wax and wane with the breeze and sunshine, and not in response to when they are most needed.
Solar production is known to be non-existent during the night, but daytime variations can be huge depending on various factors, most important of which is the cloud cover.
The saddest part is that energy storage units have not yet advanced enough to take in all of the excess generation. Because older power plants running on fossil fuels take a long time to ramp up and reduce electricity generation, they are not able to respond decisively enough to the shifting supply.
“We have a lot of stress on the grid,” said Ulrike Hörchens, a spokeswoman for Tennet, a large grid operator in Germany and the Netherlands.
For now, technological improvements that would help store additional power, and better distribute it across and between countries, are lagging.