CCC: Power system design must factor in wind drought risks

The electricity system’s future design must account for the risk that climate change will result in longer wind droughts, increasing the need for more back up gas and hydrogen generation, the Climate Change Committee (CCC) has warned.

In a new report on the decarbonisation of the power system, which has been published today (9 March), the statutory climate adviser concludes that a reliable and resilient decarbonised electricity system can be delivered by the government’s target date of 2035.

However, it says achieving this target – which is core to cutting emissions to net zero by 2050 – rests on a series of “urgent changes”.

Alongside commitments in last year’s Energy Security Strategy to boost the rollout of nuclear and renewable power, the CCC says new back up generation will be needed, including hydrogen and gas plants fitted with carbon capture use and storage (CCUS) technology.

In addition, it says, there will be a need for new storage beyond batteries, most critically the use of surplus renewable electricity to produce green hydrogen through electrolysis, which can then be stored and later used for generation.

The need for this flexible, long-term storage is heightened, according to the report, by “plausible future extreme weather and demand scenarios”, such as a repeat of January 2021, when the lowest wind speeds for at least 20 years resulted in a 16% year-on-year drop in offshore generation.

Evidence from the latest UK climate projections suggests no significant change in offshore wind generation potential during winter, when the demand for electricity is greatest.

But it says that the autumn and spring are expected to see a consistent, but small weakening in winds in future and larger climate-change related falls in wind generation during the summer.

However, the report says changes in the frequency and intensity of large-scale wind droughts due to climate change cannot be ruled out and must be considered when designing the system and conducting stress tests.

The CCC has modelled how the UK would cope with a four-week wind drought when the grid is substantially decarbonised.

It says that in this most extreme low wind scenario, up to 25GW of unabated gas generation would still be required in order to maintain security of supply.

This would be equivalent to around 3% of total annual generation, the CCC estimates, with the remainder of the demand gap plugged by imports of electricity and a mix of hydrogen and gas plants abated with CCUS technology.

In a typical year by 2035, according to the CCC’s modelling, back-up low carbon hydrogen and abated gas will provide around a tenth of annual generation, alongside other forms of flexibility.

Pushing all fossil fuel use in electricity and hydrogen supply off the grid by 2035 “currently looks implausible”, given constraints on the feasible build-out of zero carbon generation capacity.

The GB electricity system will still require significant volumes of fossil gas for use in abated gas or “blue” hydrogen power plants.

While it may be possible not to use gas by 2035, a small amount of unabated gas for electricity production to ensure security of supply would be cost-effective, says the CCC report.

And using hydrogen to provide on-demand power to meet peaks and back-up renewables appears necessary, it says.

Current government targets for 10GW of hydrogen production by 2030 are at the lower end of what it is required for the gas  to play a central role in providing low-carbon dispatchable power by 2035, according to the CCC.

The report also urges the government to fast track investment on hydrogen infrastructure, which will be required regardless of whether its decision on using gas for heating buildings, which is due to be taken by 2026.

Delays in the delivery of hydrogen infrastructure could limit the fuel’s role in the 2035 energy system, including in the provision of low-carbon back-up capacity.

It appears implausible though that the UK will be able to meet all of its hydrogen demand from domestic non-fossil production by 2035, given likely limits on the rate at which renewable generation capacity can feasibly be built. For example, the CCC points to how droughts may constrain on hydrogen production because the process can require significant water use.

Using hydrogen instead of heat pumps for heating buildings would be a much less efficient use of domestic energy resources, leading to greater need for energy to supplement them, it adds.

Asleep at the wheel

Lord Deben, chairman of the CCC, said: “We know how to do this, but government is asleep at the wheel. Recent commitments for new nuclear and renewables are welcome, but these alone are insufficient. A rapid overhaul of the planning system and regulations is needed.

“It is not clear where the responsibility lies for the design and operations of our modern energy system rests among key organisations.

“Countries around the world are now racing for this goal. The UK is further ahead than most, but we risk losing our early lead at the worst possible time.”

Responding to the CCC report, Good Energy chief executive Nigel Pocklington, said: “Businesses, investors and consumers are raring to go on net zero. The only obstacle to a decarbonised power system is a disinterested government which has consistently failed to recognise the urgency of the climate crisis and dragged its feet on implementing the right policy to unleash a renewable revolution in Britain.

“This is why we remain too reliant on polluting and expensive fossil fuels whose volatile prices have caused so many serious problems for households and businesses across the country.

“The government needs to unlock investment in cheaper and greener sources of energy, unblock the barriers to onshore wind and help pave the way for flexible storage and shifting of demand – as well as take the wider issue of energy efficiency much more seriously – if we’re to have any realistic prospect of achieving net zero.”

Lawrence Slade, chief executive of Energy Networks Association (ENA), said: “If we are to hit the government’s decarbonisation targets, secure energy investment in an increasingly competitive global market and protect long term energy security for customers then the government needs to be acting faster now.

“The CCC’s report makes clear that the solution to this challenge must involve both gas and electricity, yet policy progress is lacking. While we welcome the CCC’s assessment of the importance of hydrogen transport and storage infrastructure in delivering decarbonisation, we need to see rapid progress across both renewables and hydrogen deployment to make the 2035 target achievable.”