Renewables are replacing fossil fuel-based electricity supplies in Britain

10th May 2020 | Commercial Energy

Electricity consumers may or may not have notices the April 29 announcement by the National Grid Electricity System Operator (ESO) that the record, at more than 18 days, had been broken for the longest period since the Victorian era when no coal was burnt in Great Britain, and that they were hopeful this new record would continue to increase in the forthcoming days.

It is also worth noting that the UK Government has recently brought forward the deadline by one year to 2024 for phasing out of coal generation. This may give the impression that renewables are inexorably, seamlessly and dependably replacing fossil fuel-based electricity supplies within the UK Grid. This is not the case.


ESO failed to mention that the UK significantly ran rarely-used old Open Cycle Gas Turbines (OCGTs) on April 28, presumably to meet demand. These are much less efficient, much more expensive to operate, and, with the waste gases directly exhausted, release much more heat energy and carbon dioxide to the environment than the Combined Cycle Gas Turbines they were supplementing.

This was presumably to avoid burning coal whilst seeking to maximise a “no coal” record. OCGTs are normally only used, rarely if at all, in winter when both demand and electricity prices are much higher: otherwise they are uneconomic. The UK experienced a very mild and calm week during the “record” period which, coupled with Covid-19, had reduced UK electricity demand to around 18 per cent below seasonal average. Wind generation, however, had coincidentally virtually collapse across the UK.

In spite of this reduced demand, we were throughout the week dependent upon imported power reaching from Land’s End to Orkney via our three interconnectors to mainland Europe, supplying around and up to their maximum capability for 4000MW to keep our lights on and hospitals supplied: this being equivalent to more than three Torness power stations.

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