Blackout scenario: Weather-dependent power plants

When the European power grid collapses, it’s called a blackout. This catastrophe is no longer a fiction but a real danger. But how can such a gigantic power failure come about? There are many blackout scenarios. One of them are weather-dependent power plants.

The power grid can collapse if there is a power shortage. That simply means: more electricity is consumed than is produced in the power plants. You can find out why this leads to a blackout in our article: 5 steps to blackout – the security concept of the power grid

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Weather-dependent renewable energies

Renewable energies such as wind turbines and solar systems can lead to such an undersupply. Since these types of power plants are dependent on the local weather, they sometimes produce more and sometimes less electricity. When the sun shines strongly in summer, the solar systems generate more electricity than on dark winter days. Wind turbines also generate more electricity when the wind blows strongly and less or often nothing at all when the wind is calm.

A dense cloud cover quickly ensures that solar systems can no longer produce electricity

All of this is of course also clear to the power grid operators. And that’s why there are power plants that provide control energy in the power grid. These power plants compensate for the difference between electricity demand and electricity generation and therefore sometimes produce more and sometimes less electricity. Since these power plants are already connected to the grid, you can always react quickly to changes in the power grid. The control energy is used until an additional power plant has been started up or shut down.

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So how can a blackout happen? The answer is obvious: when there is not enough balancing energy available and reserve power plants cannot start up quickly enough. It is particularly critical when there is an unforeseen lull in the wind, because the balance between electricity demand and electricity production takes fractions of a second. On August 14, 2021, an unexpected change in weather led to such an incident. To stabilize the network, several industrial companies had to be disconnected from the power grid by load shedding in order to prevent a blackout. The first 3 levels of the 5-level security concept have already been triggered.

The dark doldrums caused problems in the power supply as early as the beginning of 2021

The weather is not always predictable. You know it all too well from the local weather report. Often the weather report reports bright sunshine and yet it is raining. You can roughly predict the weather, but an exact forecast for all of Europe, for every single wind turbine and every single solar system is simply impossible.

At the beginning of 2021 there was a dark lull. Solar systems and wind turbines produced less electricity. In order to get the power grid under control, shutdown coal-fired power plants were reconnected to the power grid. These coal-fired power plants should actually be taken off the grid as part of the energy transition. It was still possible to use these power plants to compensate. However, the coal-fired power plants and the nuclear power plants are all to be disconnected from the power grid and ultimately demolished or dismantled.

In addition, you can’t just switch such a coal or nuclear power plant on and off as you want. It takes a long time before such power plants can produce electricity again. The water has to be heated, the generator or the turbine has to be set in motion slowly, the temperature has to be increased slowly. A coal-fired power plant takes 6 to 15 hours to produce electricity when the plant is not in operation.

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Blackout scenario: Weather-dependent power plants – conclusion

So it can happen that “bad weather” means that less electricity is produced by renewable energies. The balancing energy is not sufficient to close the supply gap and the necessary power plants are not available because they either no longer exist or because it takes far too long for the power plant to start up. Then there is a blackout, without any outside influence.

All of this does not mean that renewable energies should be avoided or that the energy transition will lead to a blackout. It is, however, the case that there is an increased risk of a Europe-wide blackout due to the weather-dependent power plants.

The more renewable energies you use to generate electricity, the more power plants you need in reserve in order to be able to take countermeasures in the dark and calm winds. In order to continue the energy transition, climate-neutral power plants are needed that produce electricity despite the dark and calm winds. That is why many countries rely on nuclear power plants that do not emit any CO2 for electricity production.

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