Relying on electricity interconnectors adds to market risk

Last week the Global Warming Policy Foundation has published a short report I wrote in the use of electricity interconnectors in the GB power market. Aimed at a lay audience, the report sets out the challenges we face in our growing reliance on electricity imports, which ties in well with my recent observations on the way that a reliance on wind and solar embeds a reliance on imports into our electricity system.

In its 2023 Future Energy Scenarios, National Grid ESO (NG ESO) said:

“To manage dunkelflaute periods, dispatchable thermal power plants (gas and/or hydrogen), depending on the scenario and year, are likely to be required. A combination of LDES (e.g. Compressed Air Energy Storage (CAES), Liquid Air Energy Storage (LAES), Pumped Hydro Storage (PHS)) and interconnectors will be required to manage the network during these periods.”

So far LDES and CAES have not been deployed at scale and there is limited scope for additional pumped hydro given the geology of the UK.

That we currently rely on interconnectors is not in doubt – we import large volumes of electricity very regularly. Most of the time imports simply displace more expensive domestic generation, which sounds good in theory, but this increases prices in the exporting market above what would be the case if they did not export.

For some countries this may not matter if for example surplus wind is exported which would be otherwise curtailed with the payment of curtailment fees. But in countries such as Norway where exports use up water that might be needed to generate electricity for Norwegian consumers later on (Norway has minimal pumping capacity so once water is used it is not replaced until it rains or snow melts), which matters a lot.

In fact, Ofgem has identified electricity exports as a source of consumer dis-benefit. One might assume that the countries which currently prop up our grid with exports might realise this is bad for their domestic consumers and have a re-think. This is already happening – Norway has twice amended its Energy Act to beef up powers to restrict exports and its coalition government is divided over whether to renew the Skagerrak interconnectors when they reach the end of their lives in the next couple of years. Sweden recently cancelled a planned link with Germany on the basis it didn’t want to be connected with such a dysfunctional market!

GB electricity market becoming more vulnerable

Our electricity system is becoming more fragile. Increasing demand from electrification will coincide with the closure of the last remaining coal plant (Ratcliffe, 2 GW) this month and the last four Advanced Gas Cooled Nuclear Reactors (4.7 GW) set to close in 2026 and 2028 although some extensions are expected but not yet confirmed. In addition, the futures of Drax (4 GW) and Lynemouth (0.4 GW) biomass plants is uncertain after 2027 when their subsidies expire. 10 GW of firm, non-intermittent generating capacity could leave the grid before the end of the decade.

That’s on top of the 10.5 GW of firm capacity which has closed since the inception of the Capacity Market. Since the first long-dated auction in 2018 only 3.5 GW new large-scale gas-fired plant has been secured, but 13.5 GW of conventional capacity closed including 3 GW nuclear (Dungeness, Hinkley Point B, Hunterston B) and 10.5 GW coal (Aberthaw, Cottam, Drax, Eggborough, Fiddler’s Ferry, and West Burton A).

And it’s simply not being replaced at the necessary rate to ensure energy security – only 3.5 GW of large-scale gas generation has been secured through the Capacity Market (and a further 840 MW of CCGT at Carrington which took FID before the first capacity auction). Hinkley Point C is not expected to open before 2030.

Even if we wanted to it would be hard to replace all this lost capacity with interconnectors. Nor should we want to. The Labour Party says it wants to cut reliance on imports through use of “home-grown” energy – a sensible desire but not one we’re going to achieve with the current obsession with intermittent renewables. As I will explain in an upcoming post, a reliance on intermittent renewables guarantees a reliance on imports: when wind and solar output are low, we rely on electricity imports and gas-fired generation. But at the same time, Labour opposes any increase in domestic gas production, so a reliance on gas-fired generation equates to a reliance on imported gas.

Also, as I describe in the report, many of the countries to which we are linked with electricity interconnectors share a similar wind-led energy transition strategy and have a weather correlation of 40-65%. This means that we will often have the same weather: if it’s not windy in Britain, it may not be windy in these markets either meaning that rather than being able to export electricity to us, they will themselves want to import. The exceptions are Norway and France, but Norway is increasingly keen to protect its hydro resources for its own use, and the aging French nuclear system has experienced widespread outages twice in six years, with the French nuclear regulator suggesting that such outages could be necessary again in future as additional issues may emerge as the reactors age.

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If we don’t get our act together, we could be in real trouble in the late 2020s, with expensive, unreliable energy and all the social and economic harm that involves.