Electricity prices rocketed by 400% during yesterday's heatwave

Wholesale electricity prices in the UK rose to an all-time high on Wednesday, as a heatwave in the south pushed up demand for power.

Day-ahead electricity — the price power stations charge suppliers to put power into the National Grid — jumped from around £40 per megawatt hour to almost £160 on Wednesday, according to market intelligence firm ICIS.

The day-ahead price goes up when demand is higher and was boosted by offices and homes across the country collectively switching on their air conditioning.

The problem was made worse by the fact that many gas and nuclear power stations are offline, limiting supply.

The number of gas power stations currently shut for maintenance is at its highest level since 2009 and the country gets more than half of its electricity from gas. Others stations have suffered from unplanned power outages. An unseasonably warm September means less wind is generated by turbines, too.

Prices returned closer to normal levels on Thursday as cooler temperatures reduced demand for air conditioning.

Day-ahead prices were £48 per megawatt hour at 8 a.m. BST (3 a.m. ET) on Thursday, according to Reuters.

A spokesman for National Grid told Business Insider over email: “Electricity demand is picking up as we head into autumn, and some power stations are still offline for summer maintenance programmes, which is not unusual at this time of year.

“We are monitoring the situation and have tools and services we can call on if we need them.”

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