Solar panels still too often do not perform as well as they should

Why we write about this topic:

At parties, solar panels are a regular topic of conversation. Nowadays, more and more people decide to install them in the hope of saving some costs. Last week we wrote about how much they generate compared to last year, but they are still not performing as expected.

The need to switch to renewable energy sources such as wind and solar has never been more urgent. As the gas tap is slowly being turned off, electricity is becoming more expensive and the effects of the warming climate are becoming painfully visible, more and more people are buying solar panels. Now a press release from TU Eindhoven shows that solar panels are still not performing as expected.

Inaccurate forecasts

In the Netherlands, one in five households already has solar panels on their roofs, making us the European leader in installed solar energy capacity per capita. Before people decide to install solar panels on their roofs, often spending thousands of euros, they want to know how much power they will generate. An accurate yield estimate will tell them how many years it will take to recoup their costly investments.

In practice, however, yield estimates are often based on standard test conditions that do not take into account the exact situation on the ground. Actual performance often falls short of people’s expectations because of variations in solar radiation, heat effects, dirt, shade and module degradation.

Solar panels in Netherlands already generate more electricity than last year

In the first eight months of this year, 12.6 terawatt hours (TWh) of solar electricity was generated in The Netherlands. That is 12.5 percent more than a year ago at the same time.

Results fall short

Researcher Bin Meng decided to test the solar panels carefully. He found that the performance of the tested PV systems was, on average, 6 percent lower than expected: “The first thing I could see from my analysis is that the actual performance falls short of what is commonly predicted by simulation models. We even found a 6 percent difference from the expected performance! This implies that sellers of PV systems tend to overestimate the efficiency of solar panels on rooftops in typical Dutch residential communities.”

“This is not only bad news for customers, but it can also cause problems for manufacturers and installers if not delivering the expected performance leads to a breach of contract,” says Meng.
Click here to read the entire press release.