Can Solar Power Save Our Power Grids in Times of Crisis?
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Solar plants are repeatedly suspected of being a problem for power grids because they are comparatively difficult to regulate. When the sun is shining, they supply a lot of electricity, but when the sky is cloudy, their grid input remains low. The consequences of those fluctuations are felt all across the power grid.
On sunny and windy days, the grids are flooded with so much energy from solar and wind power plants that electricity prices on the Leipzig electricity exchange slip into negative territory. In such situations, industrial consumers are happy to receive money when they purchase energy. However, overloading the grids poses an enormous risk to their stability, as the major blackout across Spain, which happened a few months ago, showed.
Heatwave leads to rising electricity consumption
However, the problem with renewable energy is often more complex, as an analysis of the last major heatwave by the think tank Ember, which swept across Europe from June 24 to July 2, 2025, shows. The enormous amount of solar radiation set records for electricity production. Around 45 TWh were generated across Europe, an increase of 22 percent compared to June of the previous year.
These figures underline the fact that concerns about grid stability during periods of high solar radiation are not entirely unjustified. A look at Germany shows this. At the height of the heatwave, solar installations fed up to 50 gigawatts into the grid at peak times, which accounted for between 33 and 39 percent of the country's total electricity demand. Unneeded electricity can currently be distributed to battery storage systems with a capacity of 14 gigawatts and to pumped storage systems. The latter can store up to 10 GW of energy.
Nevertheless, the additional energy has not become a problem for the grids, as the authors of the study highlight. This is because energy demand also changes with high temperatures. In Spain, demand rose by an average of 14 percent, while peak loads were 15 percent higher; in France, the figures were nine and twelve percent, respectively. In Germany, an increase of six percent was recorded, while demand rose by nine percent at peak times.
France's nuclear power plants cannot deliver
In addition, the heatwave meant that energy production had to be limited elsewhere, particularly in France, which relies heavily on nuclear power to generate energy.
Production was curtailed at 17 of the 18 plants currently in operation because the water in the rivers used for cooling had heated up too much. The Golfech nuclear power plant in the south of the country even had to be taken off the grid completely. This meant that around 15 percent of France's nuclear power plant output was not available, resulting in a total capacity shortfall of 23 gigawatts.
More networking for more stability
The supply shortfall was also clearly reflected on the electricity exchange. During the period under review, some major German customers had to pay up to 400 euros per megawatt hour. This corresponds to a surcharge of around 175 percent.
Networking within Europe helped to ease the situation considerably. This is because the energy could be directed to the regions with the highest demand. An even more developed European energy network could therefore be part of the answer to supply bottlenecks and stability problems.
What is your opinion on renewable energy? Do you think the US and Europe should invest more in solar and wind power? Let us know in the comments below!
