Solar panels are increasingly failing on sunny days because the electricity grid cannot accommodate the green energy and the grid voltage is too high. About 200,000 solar installations regularly broke down last year, more than twice as many as two years ago. “The number of installations with outages will increase,” says Han Slootweg, director of grid strategy at grid operator Enexis.
The installations shut down if the mains voltage in the neighborhood exceeds 253 Volts, 10 percent higher than the regular voltage of 230 Volts. The inverters of the solar installations then switch off for safety reasons. If they continue to operate at too high a voltage, they will break or pose a fire hazard.
The solar panels no longer supply power when the inverter breaks down. Only when the voltage in the neighborhood has dropped, because the sun shines less brightly or electricity consumption increases, will the inverters switch on again.
Last year, the grid operators received 15,000 complaints about too high voltage, causing the solar panels to fail; that is more than double compared to 2021. The majority of people with solar panels do not realize that the installation no longer works during the sunniest moments. Only by viewing the yield of the solar panels on the app can you see that the panels do not supply power during the sunniest hours.
1 in 15 has problems
Two years ago, one in twenty solar power installations suffered from failures because the flood of solar power pushed the grid voltage too high. “We estimate that one in fifteen inverters now shut down on the sunniest days,” says Han Slootweg, director of grid strategy at grid operator Enexis.
The problems are increasing because 600,000 houses have been fitted with solar panels in the past two years. Electricity is now generated on the roofs of 2.6 million homes. And the more houses with solar panels in a street or neighborhood, the greater the chance that installations will fail due to excessively high mains voltage.
Two years ago there were outages at 75,000 installations, now at around 200,000 solar roofs. And that number is rising quickly. If no action is taken, in six years there will be 750,000 solar panel installations that do nothing at the sunniest moments. “The number of installations with outages will increase. We can no longer solve the faults in a few weeks. We will also tell our customers that. Once a problem has been identified in the neighborhood, we will need a few summers to solve the problems.”
The problems can be solved by using thicker cables in the ground or by adding extra or heavier transformer houses. It is impossible to predict which solar installations and how many will fail in a street or neighborhood. Anyone who lives close to a transformer house and therefore close to the ‘exit’ has less chance of outages than someone who lives further away.
No compensation
The outage usually lasts several hours. The inverter, which is the device between the meter cupboard and the solar panels that converts direct current into alternating current, automatically switches on again. Older inverters can sometimes remain off for hours. According to Netbeheer Nederland, the loss of power is manageable. For example, only 1 percent of households that suffer from outages would miss out on more than 5 percent of hours of sunshine and thus at least 60 euros per year, but in some cases this could also be much more. There is no financial compensation scheme, because it concerns ‘force majeure’.
The yield you lose is limited
Han Slootweg
Grid operators map the overvoltage reports from smart meters to solve the biggest problems and, if possible, to strengthen the grid preventively. Anyone who wants to purchase solar panels and wants some certainty that they will continue to work even at the sunniest moments can check with the grid operators based on their postal code whether there are voltage problems in the neighborhood or complaints about failing installations.
Slootweg emphasizes that the problems are not a reason to abandon solar panels. “The installation will not work for a limited number of hours. If it takes two years before we solve the problem in the neighborhood, you won’t have any problems for many years to come. You take panels for 15 years or longer. The yield you lose is limited. And it is lower than the feed-in tariff that more and more energy companies charge. If you look at the facts, the failure is not a reason to abandon solar panels, especially when you see that energy prices are rising and solar panels are becoming cheaper.”
He also advocates using electricity when the sun is shining, which can also limit outages. “Charge that car when you work from home and it is sunny. Even do that if you don’t have solar panels, because you help the entire network.” Grid operator Stedin started a public campaign this week with the same aim: use the solar power if it is available.
View our Q&A about energy here: Buying solar panels is still so attractive:
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