Why is electricity demand increasing during the summer?

Summer has traditionally been a period of lower electricity demand across Great Britain. With longer daylight hours and warmer temperatures, there is typically less need for lighting and heating, resulting in reduced pressure on the electricity network compared to the winter months.

However, this summer's extreme heat has challenged that long standing trend.

For only the third time in its history, the National Energy System Operator (NESO) has issued an Electricity Margin Notice (EMN), requesting additional electricity generation or for large energy users to reduce demand during the evening peak. An EMN is not an indication that power cuts are expected, but it does signal that the balance between electricity supply and demand has become tighter than normal.

So, what's driving this change?

The biggest factor is the significant increase in the use of air conditioning and cooling systems. While air conditioning has historically been less common in the UK than in many other countries, repeated heatwaves have seen demand grow rapidly. Retailers have even reported air conditioning units selling out nationwide as businesses and households look for ways to stay cool.

As a result, the additional electricity required to power cooling systems has outweighed the usual reduction in demand from lighting and heating. Instead of seeing the typical seasonal dip in electricity consumption, the UK is experiencing higher than expected summer demand.

Adding further pressure is the current generation mix. Wind output has remained relatively low during the heatwave, meaning gas fired power stations have been required to generate a much larger proportion of Britain's electricity. As gas often sets the wholesale electricity price, greater reliance on gas generation, combined with elevated wholesale gas prices, continues to increase costs across the market.

The hot weather has also affected electricity imports from Europe. High temperatures in France have reduced the output of some nuclear power stations, as warmer river water limits their ability to cool reactors efficiently. This has reduced available generation at a time when electricity demand is rising across several countries.

Earlier this year, both National Gas and NESO forecast that Britain would have sufficient energy supplies throughout the summer. However, the recent spell of exceptionally hot weather demonstrates how quickly demand patterns can change and why system flexibility has become increasingly important.

As the UK experiences more frequent periods of extreme weather, electricity demand is likely to become less predictable. Managing consumption, investing in flexible energy solutions and improving efficiency will all play an increasingly important role in maintaining a resilient and affordable energy system.

This summer is proving that high electricity demand isn't just a winter challenge anymore.