To stop gas and coal power plants and switch completely to electricity from solar and wind, the Netherlands and Germany need more large batteries and more green hydrogen. To avoid power shortages, companies should scale back or shut down production during dark and windless periods. Electric cars should then charge less and supply power back to the grid.
This emerges from by grid operator Tennet into an energy system without CO2 emissions (net zero) that is both reliable and affordable. It is the first study ever to look at the security of electricity supply once all power is generated CO2-free. Because it is not yet known when that will be, the study does not name a specific year. However, it assumes scenarios that predict it will be sometime between 2030 and 2050 in the Netherlands and Germany, the two countries where Tennet manages the high-voltage grid. The question posed in the study was: how can we get all of our power from renewable sources in the future and still continue to supply enough electricity?
First climate-neutral continent
To meet the Paris climate goals and limit global warming to 1.5 degrees, Europe wants to reduce its CO2 emissions by 55 percent by 2030. With the and the , the EU even wants to be the world's first climate-neutral continent by 2050. In other words, with zero CO2 emissions. To achieve that goal, countries must stop coal and gas power plants and get their electricity from solar, wind and other renewable sources. In the Netherlands and Germany, 20 and 46 percent of electricity was green in 2020, respectively. By 2030, that should already be 80 percent. Germany wants its energy system to be completely climate neutral by 2045. In the scenarios currently being examined, the growing demand for power from electric driving, electric heat pumps and electrification of processes in industry has already been factored in.
Although on sunny and windy days there is a surplus of green power and the price of electricity is even , there are also periods with little sun and wind. Those periods are referred to with the German word "," a combination of "Dunkelheit" (darkness) and "Flaute" (little wind). At such times, there is a threat of a shortage of electricity in the near future. The study indicates how the Netherlands and that Germany can get through those periods without electricity failure.
Batteries and hydrogen
At present, gas-fired power plants are used to generate electricity at such times. Those will soon be gone. According to the report, nuclear energy is an important constant CO2-free source of electricity in the Netherlands - Germany is stopping it - but you can't just turn nuclear power plants on and off. Therefore, according to the study, with long-term storage capacity are needed. Preferably batteries that can store power for 24 hours or longer. Small home batteries that can store power for 2 hours at most play no role in the security of power supply. Yet it is not batteries but green hydrogen power plants that should provide most of the power during extended periods of "Dunkelflaute. Between 4 and 16 gigawatts in the Netherlands and between 8 and 56 gigawatts in Germany. The power plants should have considerable capacity, but are only needed a few times a year, according to the study. As a result, they end up supplying only 10 percent of all electricity. That hydrogen must be made from water via electrolysers using wind and solar power to avoid emitting CO2. To control costs, it must be done at times when there is a surplus of green power.
To have enough green hydrogen on hand, both countries must increase their storage capacity. Germany must be able to store 44 to 90 terawatts of green hydrogen, the Netherlands 22 to 44 terawatts. That is a fraction of current gas storage capacity, but it is not always suitable for hydrogen. It is also questionable whether hydrogen can be stored in empty salt mines and gas fields. Therefore, new investments are needed.
Reducing demand for power
One of the most important and cheapest ways to supply enough power, according to Tennet, is to reduce demand when there is little supply from solar and wind. In jargon, this is called demand-side response (DSR). At times like that, industry has to reduce its demand for power or even shut down production. Sometimes for days at a time. Shutdown is called that. Electric cars have to slow down or even stop charging and feed power back to the grid via bi-directional plugs. They act as driving batteries at that time, although the question is how many vehicles are connected to a charging station or the grid at such times. According to Tennet, this must become the first priority if both countries want to secure the supply of power.
Saving a quarter of power
"We have to adjust the demand for power to the supply during 'Dunkelflaute,'" said Tennet spokesman Jorrit de Jong. "The biggest hit then is in industry. We charted that earlier. By scaling back or switching off production, we can save 3.5 to 4 gigawatts of electricity. That's almost a quarter of the total power demand of 12 to 18 gigawatts." He acknowledges that this is not a fine message for companies. "But several companies are already doing it. Companies with a heat boiler turn down the temperature at times like that, freezer houses start using more when the price of power is lower, and a company like AkzoNobel has an electrolyser in the Botlek that allows it to scale up or down its power consumption 10 percent," he says.
International power highways
The final link in the energy transition is the high-voltage grids that allow the Netherlands and Germany to obtain green power from abroad during windless and sunless periods. International power highways, Tennet calls them. These can solve 25 percent of the power shortage. But if it is not windy or foggy in the Netherlands or Germany, it is obvious that this is also the case in neighboring European countries and that they also have a power shortage. Therefore, both countries should get green power from countries like Norway and France, where there is more hydro and nuclear power available. Those countries would have to have a surplus.