It also trades energy with the continent through a growing network of cables capable of supplying more than 10% of UK demand.
Supply and demand must be constantly adjusted across the network to avoid blackouts, with ESO stepping in to smooth out imbalances left by the market.
The system across Europe is currently under strain, with half of France’s nuclear fleet offline due to maintenance or corrosion issues, while hydropower production is also low.
Although some French nuclear plants will come back online in the winter, output will still be lower than normal.
There are also concerns that Russia will further choke off gas supplies to Europe as it eases sanctions, cutting off a key source of fuel for power generation.
Coal-fired power stations in the UK and on the continent have been asked to remain operational for longer than planned for back-up.
The UK has typically imported power from France during the winter to help meet its own demand.
However, forward prices currently indicate that France will “need all the power it can get” from the UK during the winter peak, according to Phil Hewitt, director of EnAppSys. He added: “Winter is the approaching iceberg.”
Matthew Grant, electricity market specialist at Baringa Partners, said that while last week brought up some unique circumstances, “they were nothing like the kind of supply and demand challenges we might see in the winter : Weather-related events that drive demand for electricity and wholesale electricity.” prices”.
He said: “When it comes to energy demand over the coming months, a lot will depend on the weather. The challenge we face is when Western Europe faces the same conditions, whether it’s cold or hot, it drives demand and high prices in a similar environment. through the markets.”
Luke Ansell, analyst at Cornwall Insight, said the market was “incredibly tight” last week and needed to evolve to better cope with high temperatures as they are likely to become more frequent.
Ansell said capacity last week worsened because generators were not connected for summer maintenance, most of which will return in the winter. But prolonged periods of cold weather and low wind emission could still cause tightness.
Describing the circumstances last Wednesday, ESO said: “We were bidding in a tight market and market prices were high that day because Europe also wanted the power. We managed the system and kept the electricity flowing to the Southeast.”
It added that the warnings calling for more generation on Monday were due to “a combination of factors including high exports, low wind, expected plant maintenance outages, higher-than-usual demand and a small reduction in gas generation “.
A spokesperson said: “Capacity market warnings are automated and do not take into account all the factors our engineers are working on. Based on our control room assessments and submitted data, we were confident that the margins of “electricity were enough”.