The Solar Eclipse Is Today: What It Means for Your Solar Panels and Battery
We’re expecting a lot of people to Google this today:
“What happens to solar panels during an eclipse?”
Here’s the answer.
They generate less electricity while the sun is obscured. Then, a few minutes later, they’re back to work.
That’s it. No damage. No drama. Just a temporary dip in output, roughly the same as a heavy bank of cloud rolling over.
Because solar isn’t measured in moments. It’s measured over months and years.
Tonight the UK is in the path of a partial solar eclipse, with up to 96% coverage depending on where you are. It’s the most significant eclipse visible from British soil since 1999, and the next one won’t come until 2090. Most of us won’t be around for that one.
Your panels will be fine. But tonight is a genuinely useful reminder about something worth thinking about.
What’s Actually Happening Tonight
The UK is in the path of a partial solar eclipse, meaning the Moon won’t fully cover the Sun from our vantage point. But “partial” is doing a lot of heavy lifting there. Across most of the country, coverage will be between 90% and 96%.
Here’s how it breaks down by city, with peak eclipse times:
| City | Coverage | Peak Time (BST) |
|---|---|---|
| Cardiff | 93.2% | 19:13 |
| Belfast | 93.1% | 19:08 |
| Liverpool | 91.8% | 19:10 |
| Birmingham | 91.8% | 19:11 |
| London | 91.4% | 19:13 |
| Manchester | 91.4% | 19:10 |
| Glasgow | 91.4% | 19:06 |
| Edinburgh | 90.7% | 19:05 |
If you’re in Cornwall, you’ll see up to 95.8% coverage, making it one of the deepest partial eclipses anywhere in mainland Britain tonight.
The eclipse runs from roughly 6pm to 8pm BST, with maximum darkness around 7:10pm. That’s a roughly two-hour window where your panels will be working at a fraction of their normal capacity.
To be clear: the eclipse won’t damage your panels. Solar cells don’t care whether output drops because of clouds, evening shade, or a once-in-a-generation celestial event. They’ll ramp back up the moment the Moon moves on.
What It Means for Your Solar Output
A typical 4kW system on a clear summer evening generates around 1.5-2kW at 7pm. During tonight’s peak eclipse, that drops to as low as 100-200W. The equivalent of pulling thick curtains across the sky.
And 7pm is not an idle hour. People are home. Kettles are on. Ovens are firing. Demand is climbing exactly as your panels go quiet.
This is the mismatch that exists every single day, not just during eclipses. Panels peak around midday. Demand peaks morning and evening. The eclipse just makes it visible.
Panels only: you’re back on the grid
No drama. No flickering lights. The grid covers the gap automatically. But you’re now paying 24-30p/kWh for electricity you’d otherwise be generating for free. For one evening, fine. As a daily pattern across autumn and winter? That’s real money leaving your home.
Panels and battery: you don’t notice a thing
A well-charged battery absorbs surplus solar all day. By the time the eclipse kicks in, it’s close to full. When panel output falls, the battery takes over quietly, automatically, without touching the grid.
That’s the whole point of storage. Not just for eclipses. For every cloudy afternoon, every winter morning, every evening when the sun is down and your home is still running at full tilt.
The eclipse is a two-hour demonstration of a gap that exists 365 days a year.
Why a Battery Changes the Maths
Our battery customers save an average of £1,032 in their first year. Not a projection. What we actually see across installations nationwide.
Here’s where that saving comes from:
- You use your own electricity instead of exporting it cheap. Most export tariffs pay around 15p/kWh for surplus solar. You buy it back at 24-30p. A battery means you keep it and use it yourself.
- You cover your evenings without touching the grid. Panels peak midday. Demand peaks morning and evening. A battery bridges that gap every day of the year, not just during eclipses.
- You can charge overnight on cheap tariffs. Systems like Octopus Go let you fill your battery at off-peak rates and discharge during expensive peak hours. That alone adds hundreds on top of the solar benefit.
The Energy Saving Trust estimates UK households generate 3,000-4,500 kWh from solar per year. Without a battery, a large chunk of that gets exported at 15p. You then buy it back at 24-30p. A battery closes that gap permanently.
What about backup power?
One thing worth knowing: a standard grid-connected solar system will shut down during a power cut. That’s a safety feature, not a fault. It prevents electricity flowing onto lines while engineers are working on them.
If backup power matters to you, that requires a battery with islanding capability and the right inverter configuration. It’s entirely possible to design a system that keeps your essentials running during an outage. It just needs to be specified correctly from the start.
If you’re not sure what size battery makes sense for your home, this guide walks through it. Or if you’re still weighing up whether storage is worth it at all, here’s the honest answer.
Go Outside and Watch It
Before we wrap up: please do go and watch this. Events like this are genuinely rare. The last comparable eclipse over the UK was in 1999. The next won’t come until 2090.
The peak hits between 7:05pm and 7:13pm BST depending on your location. Get outside a few minutes before, face west, and use proper eclipse glasses (ISO 12312-2 certified) or a pinhole projector. Never look directly at the Sun, even when 90%+ of it is blocked.
The Royal Museums Greenwich have a great guide on safe viewing if you need one.
Your panels will handle themselves. They’ve seen worse on a grey November Tuesday.
Thinking about adding battery storage? Whether you want to make the most of today’s solar generation or just stop selling your electricity cheap and buying it back expensive, we’d love to help. Get in touch with the Project Solar UK team for a free quote and find out how much a battery could save you in year one.
