On 17 May 2026, Great Britain generated 89.74 GWh from solar in a single day — smashing the previous record of 87.6 GWh set on 1 April 2025. Here's what happened, why it matters, and what your panels contributed.
89.74 GWh. The UK just did that in one day.
I checked the Sun Hours app at about half seven this evening and did a double-take.
The bar had gone green. Not nearly there. Not almost. Green. 100%. Record broken.
89.74 GWh. That's the new number. The previous one was 87.6 GWh, set on 1 April 2025 — which itself felt enormous when it happened. Today we cleared it by more than 2 gigawatt-hours.
To put that in context: 2 GWh is roughly the daily electricity consumption of a city the size of Oxford. We generated that on top of the previous record, from sunlight, on a Sunday in May.
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What the numbers actually looked like today
The peak hit 10.67 GW at 14:00. That's 10,670 megawatts — enough to power 25.6 million homes simultaneously, in one afternoon, from panels on rooftops, fields, and yes, balconies.
The day built steadily from sunrise, the curve on SolarUK looking like a near-perfect bell. No weather drama. Just a long, warm May day doing exactly what May days are supposed to do — and an ever-growing fleet of solar panels doing exactly what they were designed for.
By the time cloud rolled in over the north-west, the total was already past the old record with hours still to go.
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Why May? Why now?
Here's the thing people get wrong about solar records: it's almost never the hottest day.
Panels hate heat. Above about 25°C, efficiency starts dropping. The absolute best conditions are cool, bright, and long — which is basically a description of a good May day in southern England.
Add to that the fact that the UK now has over 21.5 GW of installed solar capacity — up 13% on the previous year alone — and the maths makes sense. More panels pointing at the same sky means every clear day generates more than the same clear day last year.
The UK's instantaneous power record of 15,420 MW was set on 23 April 2026. Today's 10.67 GW peak didn't touch that — but today was never about peak power. It was about total volume across the whole day, and on that measure we just rewrote the book.
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Your plug-in panel was part of this
If you have a balcony solar kit or a plug-in panel on your south-facing wall, you contributed to today's 89.74 GWh.
That's not a small thing. GB solar generated over 18,000 GWh in all of 2025 — a 30% increase year on year. The residential and small-scale sector is a significant and fast-growing slice of that total.
Every 800W kit reducing your draw from the grid shows up in the national numbers. The 89.74 GWh includes balcony panels in Bristol, garage-roof kits in Yorkshire, and flat-roof setups in Manchester. Your panel was there.
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How many more records are coming?
A lot. The UK added roughly 1.9 GW of new capacity last year. That pace is accelerating — capacity is set to rise toward 60 GW over the coming decade, and solar industry bodies say records are now essentially guaranteed to fall each year.
Which means today's 89.74 GWh will probably look modest by 2027. Maybe even by this summer.
That's not a reason to be less impressed by today. It's a reason to pay attention. These records are being broken by infrastructure you can watch happen in real time, on a free website, every five minutes.
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Watch the next one
SolarUK shows live national generation, today's generation chart, and a running tally against the all-time record. When the next big day is building, you'll see it hour by hour.
The Sun Hours app shows your personal solar forecast — so on the next record-contending day, you'll know before it happens whether your panels are going to be part of it.
Today was special. There are more coming. ☀️
Watch the next record happen live.
SolarUK updates every 5 minutes straight from the national grid. When the UK is pushing toward another record day, you'll see it in real time — plus your own local forecast in the Sun Hours app. Free, no account.