Skip to Navigation

Solstice set to power up the UK with solar energy

21 June 2023

As the summer solstice hits, more sun and longer days result in more solar power for homes and businesses across the UK.

This year’s solstice also marks European Solar Day, a Europe-wide campaign promoting the use of solar energy for the production of electricity, heating and cooling.

Solar power made up 4.4% of the renewable mix in 2022, taking up just 0.1% of all land in the UK. It regularly accounts for more than a quarter of power generation.

This year is expected to set a new record for rooftop solar installations.

Energy experts predict a bumper solar boost to the UK’s energy grid as the nation looks forward to the summer solstice and the upcoming European Solar Day.

This Wednesday marks the longest day of the year, across the northern hemisphere. As the days get longer, skies are clearer, and there is plenty of sunlight, the UK is primed to generate the most solar power during the summer months. More than a quarter of the nation’s power demand is regularly met by photovoltaic technology when the sun is high in the summer.

With over 14 hours of daylight expected each day between May and August, solar industry experts expect the coming months to be a great time to generate renewable electricity – which can also be stored and used later. More and more homes are buying battery storage systems to pair with their solar panels, and the same technology is steadily becoming an important feature at grid scale too.

Last summer solstice (21 June 2022), the UK generated 8.67 gigawatt-hours of energy from solar farms and roof-mounted panels, enough to power a million homes over the day or make hundreds of millions of cups of tea.[1]

Solar has been rapidly growing as a source of renewable energy, due largely to the energy price crisis, with the Government committing to a five-fold increase in solar capacity in the UK by 2035.

Solar Energy UK Chief Executive Chris Hewett said: “As summer well and truly hits the UK, it’s an exciting time for the solar industry. With longer and sunnier days, solar power produces high yields of energy, some of which will be stored in batteries for later use. Summer in the UK can often bring unpredictable weather, which is why solar generation works well in tandem with other renewable energy sources, such as wind. During sunny weather, it’s typically not windy, so when there’s not enough wind to turn the turbines solar, solar can help make up that difference – and vice-versa.”

As Britain braces for heat waves, false accusations have been made about whether solar panels work effectively in the heat. But industry groups and experts have assured that more solar power is produced in the summer than any other time – regardless of how hot it gets.

The peak rate of solar-powered generation is generally encountered at midday in April or May due to cool but bright weather conditions. However, the longer, warmer and sunnier days around the solstice mean that more power is produced overall. The amounts of energy produced over May, June, July and August are roughly equal.

UK’s leading technical expert on the technology, Alastair Buckley, Professor of Organic Electronics at the University of Sheffield, said: “High temperatures affect all sorts of components of our electricity systems – losses on transmission cables rise, transformers, coal, nuclear and gas power stations become slightly less efficient, and energy output is potentially limited as access to cooling water can be restricted. The fact that solar generators are distributed within the electricity system and reduce our reliance on centralised thermal generation, I believe, makes our electricity system more resilient in the summer. It’s a myth that solar panels wilt or break during a heat wave. While photovoltaic panels convert a slightly lower proportion of sunlight into electricity in hotter conditions, these high temperatures we’re going to see over the coming months will only marginally affect the overall output of solar power – it’s a secondary effect. In short, if it’s sunny and hot, you are going to see a great power output.”

More than one million homes can now attest to the performance of solar power, simply by looking at how their utility bills have been slashed. More generally, solar farms are helping to cut bills and reliance on imported natural gas for everyone in the nation. In combination with grid-scale storage, they will become a more and more important part of the energy mix as the UK’s energy mix steadily decarbonises.

The solstice also marks European Solar Day, a Europe-wide campaign promoting the use of solar energy for production of electricity, heating and cooling. What started in 2002 in Austria as the ‘Day of the Sun’, is now a multi-country effort with thousands of local events involving organisers who range from solar equipment manufacturers, to church communities and local governments.

By joining forces, we can pave the way for a sustainable, resilient, and responsible future.

Join us #EuropeanSolarDay #SolarRevolution

[1] PV Live

– ENDS –

For more information or to request an interview, please contact: or Solar Energy UK Senior Communications Adviser Gareth Simkins, |