Households in Spain on the regulated tariff have noticed something odd this summer. In the early afternoon, electricity costs barely a cent. By the evening, the same unit can cost 25 times more. It is not a billing error. It is the sign of a power market turned upside down by solar. And it raises an obvious question for anyone watching from Britain: could the same thing happen here?

Why afternoon power is almost free in Spain

Spain's regulated tariff, known as the PVPC, is recalculated every hour and tracks the wholesale market directly. It is open to homes with up to 10 kW of contracted power. On sunny afternoons the energy part of the price falls to around one cent per kilowatt hour. By the evening it climbs back towards 25 cents. The same kilowatt hour can end up costing 25 times more depending on the time of day. One caveat matters. Only the energy element drops that low. Network charges and taxes still apply, so the bill never truly reaches zero.

Solar has turned the day upside down

The cause is the sun. Around midday, Spanish solar farms produce more power than the grid can absorb, and that glut drags prices down. When the sun sets, generation collapses just as homes switch everything on, and the price jumps. The cheapest hour is no longer the middle of the night. It is now the early afternoon. In the second quarter of 2026 alone, Spanish wholesale prices turned negative for close to 600 hours. A few years ago that would have been unthinkable.

Could it happen in Britain?

To a degree, it already is. Britain has no hourly regulated tariff like the PVPC. The Ofgem price cap sets a ceiling on the unit rate you pay per kWh, not a price that moves hour by hour, and standing charges apply on top. But the wholesale market behaves in much the same way. Prices went negative for 101 hours in the first part of 2026. Last April, almost 17% of midday half-hour periods settled below zero. In June, they fell as low as minus £25 per megawatt hour for nine hours running. Strong offshore wind and unusually high summer solar are pushing British wholesale prices below zero more and more often. Forecasters expect more than 1,000 negative-price hours a year by 2027. You can follow today's wholesale electricity prices to see the pattern for yourself.

How to make the cheap hours work for you

For most homes on a standard tariff, none of this changes the bill directly. The savings only show up if your price follows the wholesale market. A growing number of time-of-use tariffs now do exactly that, charging less when demand is low and generation is high. If you are on one, the trick is simple. Run the washing machine, the dishwasher, the heat pump or the car charger in the middle of the day, when solar output peaks. In a market like this, when you use power matters almost as much as how much you use. There are also plenty of everyday ways to cut your electricity use that pay off on any tariff. As solar and battery storage keep growing, daytime looks set to become the cheapest window more and more often, in Britain just as in Spain.