Adam Smith Institute

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Dunkelflaute, DESNZ, and Departmental Questions

The new Department for Energy Security and Net Zero (DESNZ) is due to publish an energy strategy by the end of this month, according to oral evidence given to the Public Accounts Committee on 23rd March.

This responds to a ruling by the Hon. Mr Justice Holgate on 18th July 2022 that the government had no 2050 energy plan and should produce one Pronto. He called, in effect, for a detailed roadmap showing how net zero will be achieved along with targets and outcomes published annually.

The reason for the delay, according to the DESNZ Permanent Secretary, is that they have so many mini-strategies and thousands of simulations. Q23: “We actually have a number of plans already to help us to achieve that.” Followed by Q24: “The Department runs thousands of simulations…” In other words, DESNZ is unable to see the wood for the trees.

The wood, as our written evidence to the PAC pointed out, is really quite simple. Due to weather variability i.e. “dunkelflaute” - a period of time in which little or no energy can be generated with wind and solar power - no amount of renewables will suffice. They will have to be backed up by nuclear, natural gas (plus carbon capture and storage – CCUS) and electricity imports from Norway and the continent, in turn offset by exports when the winds favour the UK. In other words, just four sources. DESNZ envisages three others: batteries, biomass and hydrogen. These, as our written evidence explains, are bunkum.

And how will total electricity demand be divided between the four sources? DESNZ expects that 2050 electricity demand would be less than double current levels: 580TWh compared with 300TWh now. A decarbonised 2050 power market implies that almost all UK energy will take the form of electricity. If 2050 total energy needs prove to be about the same as in 2020, electricity supply will have to increase by nearly seven times. The Chancellor’s budget forecast a 15% reduction due to energy efficiencies but that still means DESNZ is under forecasting by about three times…

DESNZ’s oral evidence did not disclose the split between the four sources but for renewables they talked about capacities, not delivery. Wind seldom exceeds 50% of its nominal capacity. Wind capacity in 2021 was 25.7 GW. Wind power only reached 50% of capacity for 2.3% of the time (205 hours). Equally importantly wind failed to meet 20% of demand for 58.8% of the year (5,154 hours).

For nuclear, the Permanent Secretary talked about “up to 24 GW” being added but only Sizewell C was specified (3.2GW). (Q41) The Nuclear Industry Association’s written evidence that 24 GW is an underestimate is surely correct. 56 GW seems more likely.

Nuclear will, in fact, need to move quickly to the SMRs the Chancellor highlighted in his budget but only had partial acknowledgement by the DESNZ team. We will need about 100 but we had no outline of how many suppliers would be considered, how many chosen or how many SMRs needed or timescale. Recognising the need and specifying how we will get there are very important as is also the case for CCUS but a government department preoccupied by “sophisticated modelling” appears to have has no time for simple commercial implementation.

The DESNZ team was reluctant to share with the MPs even the information that will be released next week. This is my final point. Delay and obfuscation are cloaks for incompetence. We need a SAGE-type team of top scientists and engineers openly to advise DESNZ and blow away the cobwebs. Such advice should be open to peer review. If DESNZ carries on fiddling while CO2 levels rise, we will not get to net zero this century.

Bibliography:

https://committees.parliament.uk/oralevidence/12875/pdf/

https://www.judiciary.uk/wp-content/uploads/2022/07/FoE-v-BEIS-judgment-180722.pdf

https://committees.parliament.uk/writtenevidence/119204/pdf/

https://www.bmreports.com/bmrs/?q=generation/fueltype

https://committeIbides.parliament.uk/writtenevidence/119201/pdf/

https://committees.parliament.uk/writtenevidence/119204/pdf/