Solar Efficiency and High Temperature

I spoke, briefly, to BBC journalist Tom Singleton about our solar panels and how they're coping in the heat.

BBC headline "Why record heat doesn't mean record solar power".

The good news is that solar panels work when it is sunny (duh!) - but the bad news is that electronics are generally less efficient when it is hot.

Here are a few examples.

July 16th was a few days before the heatwave:

A beautiful summer's day. Not a cloud in the sky. And it generated over 25kWh of electricity.

So how did the soaring temperatures change things? July 19th was the hottest day on record. Here's how the panels performed:

Not bad at all! Around 12% lower on the hotter day than the cooler day. You can see from the graph that the maximum generation at solar noon is lower on the hotter day.

I don't regularly monitor the weather - but perhaps I should! It is on cooler days that our panels can hit their maximum generation. In May, because it is cooler, the photovoltaic conversion is more efficient:

As you can see, the panels clip off just under 4kWp. That above example has a lot of cloud cover. Let's take a look at July a few years ago. A a few clouds in the sky, with the temperature hitting about 19°C:

Significantly better energy generation!

So, based on all my data, it's apparent that solar panels continue to work well in the new extreme heat that we have. They work better when it is colder.

Well, OK, not in the extreme cold!

4 thoughts on “Solar Efficiency and High Temperature

  1. I wonder if solar panels in sunny places like, say, California or Morocco are configured differently to those in temperate northern Europe to account for this phenomenon?

    1. @edent says:

      I know places use water cooling - and then capture that as thermal energy. I think in sandy places, the biggest issue is keeping the panels clear and free of abrasions.

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