Short answer
There is no fixed cleanest hour every day. Windy overnight periods, sunny middays and lower-demand windows are often cleaner, while still evening peaks with more gas generation are often more carbon intensive.
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Great Britain covers England, Scotland and Wales; Northern Ireland operates in a separate electricity market.
Cleanest time today
Use the live module above for the next low-carbon forecast window, then compare it with current renewables, gas generation and demand. The recommendation is emissions-focused: price and smart-tariff windows may differ.
What makes electricity cleaner?
Electricity is generally cleaner when more of the mix comes from wind, solar, nuclear, hydro and other low-carbon sources. It is generally more carbon intensive when gas or other fossil generation provides a larger share.
Best times for EV charging
If you can choose when to charge, overnight can be good when wind is strong and demand is lower. Solar-heavy midday periods can also be cleaner, especially in brighter months. Smart tariffs may add a price signal, but price and carbon are not identical.
Best times for appliances and batteries
Dishwashers, washing machines, immersion heaters and home batteries can often shift by a few hours. The practical rule is simple: avoid unnecessary use during high-demand, high-carbon peaks when a cleaner window is nearby and convenient.
How wind, solar, demand and imports affect the answer
Wind can make overnight electricity very clean. Solar can improve the middle of the day. Demand peaks can push gas higher. Imports can help or hurt depending on where they come from and what is generating in the exporting country.
FAQs
Is overnight always the cleanest time?
No. Overnight is often lower demand and can be clean when wind is strong, but a sunny midday or another windy period may be cleaner.
Should I always avoid evening electricity use?
Not always. Some use is unavoidable. But flexible tasks can often move away from early evening peaks.
Is this the same as the cheapest time?
No. Cheap periods and clean periods often overlap, especially with high renewables, but tariffs and market prices are separate signals.
Related pages
Weekly brief
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A short, source-backed brief on renewables, gas, carbon intensity, records and cleaner electricity windows.
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