Grid as a bottleneck Why the feed-in of solar power should be slowed down
On sunny summer days, solar power systems supply more energy than the grid can absorb. It should therefore be possible to throttle these small power plants remotely. This is a loss for the owners.
No time? blue News summarizes for you
- At peak times, solar power plants in Switzerland generate more electricity than the grid can absorb.
- That's why solar installations can now be throttled by the grid operator if they generate too much electricity.
- This means a loss for the owners concerned, as they will not receive any feed-in remuneration.
- As it is currently not yet possible to throttle remotely, new systems will probably not be connected at all for the time being.
This is good news for the energy transition: solar installations in Switzerland generate as much energy as the Beznau nuclear power plant and are expected to overtake it by 2025. However, the amount of solar power is a major challenge for the electricity grid. This is because it does not flow evenly, but fluctuates depending on the amount of sunlight.
During the midday hours, the solar systems bring the electricity grid to its limits in some areas. This is because the lines in neighborhoods or villages are not designed for such volumes of electricity. Transformer stations must also be powerful enough to absorb and transmit the amount of solar power on long summer days.
The expansion of the electricity grid is therefore part of the energy transition. According to a 2022 study by the Swiss Federal Office of Energy, this could cost between CHF 30 and 45 billion.
PV systems overload the grid in summer
The costs are heavily dependent on how much electricity the grid should be able to absorb at any given time. In other words, whether it should be able to cope with the feed-in peak at midday in summer. If it were dimensioned in this way, grid capacity would lie idle for a large part of the year because much less electricity would then flow into the grid from the PV systems.
A cost-efficient grid, on the other hand, is not designed for the absolute peak, but for the optimum over the course of the year. However, if solar systems can no longer deliver their full output, it must be possible to either store the electricity locally or regulate it down.
For the owners of the systems, this means that they cannot sell electricity for which they receive money in less productive times. The legal basis for this was created by the voters with the blanket decree. The details are regulated by the new Electricity Act, which is expected to come into force on January 1, 2025.
Some PV systems are not connected for years
Grid expansion is also about how quickly it grows with the increasing amount of solar power. By throttling systems, the pressure on those who are driving and financing the expansion of the distribution grid is reduced, as a representative of BKW explained to SRF.
The alternative to throttling is that new plants are not connected to the grid at all because it cannot absorb any more electricity than it already does on peak days. As a result, some people wait years for their system to be connected to the grid and to be remunerated for the electricity they feed in, as the NZZ writes.
Other proposed solutions include flexible tariffs. In times of surplus solar power, this would then hardly be remunerated or not at all. If system operators want to react to this, they also need a technical solution.
Owners of PV systems who always want to use their full output must store the electricity at certain times. However, these batteries are still very expensive. Nevertheless, the industry association Swissolar, for example, has been communicating for years that system owners benefit financially the more they consume of their self-generated solar power.