Long-duration energy storage can reduce curtailment of renewables and grid congestion, bringing down electricity costs and allowing a greater amount of renewable power to be integrated into the system. Developing more would help to insulate the UK from future energy supply shocks such as the 2021–2022 energy crisis following Russia’s incursion into Ukraine, suggests the report.

The UK government says it wants to deploy enough storage to balance and decarbonise the electricity system by 2035. However, the Committee warns that the country is not on track. Long-duration energy storage facilities can take 7–10 years to build, so action is needed now to ensure the private sector sees a clear case to invest, and to slash planning delays and grid connection queues if the required infrastructure is to be in place by that target date.

Whilst the Committee welcomed the government’s recent reforms to the energy system, such as committing to produce a Strategic Spatial Energy Plan (SSEP) that sets out what needs to be built, where and when to deliver on 2035 targets, the report also raises concerns that it is not clear who will be responsible for implementing this plan or how future energy supply crises will be managed.

Key recommendations in the report include calling on the government to:

• Commit to a strategic reserve of long-duration energy storage which will be vital for energy security.
• Urgently make key decisions and coordinate the delivery of its energy system plan.
• Set an explicit minimum target for long-duration energy storage.
• Set out the details of its long-duration storage business model.
• Clarify the role of hydrogen in the future energy system and deliver ‘no-regrets investments’ in hydrogen production and storage.
• Act with urgency and reduce timelines for grid connection and planning delays.
• Engage and communicate with the public to ensure support for vital hydrogen and electricity infrastructure.

Baroness Brown, Chair of the House of Lords Science and Technology Committee, commented: ‘A strategic reserve of electricity storage is a critical investment to secure the UK’s energy supply against future shocks, but the government is still equivocating over whether it is necessary to invest in one.’  

It is hoped that policy will be in place by the end of 2024, providing much needed market confidence and encouraging further private investment in long-duration electricity storage projects.

SSE Renewables was among companies welcoming a January government consultation [and study] on unlocking investment in long-duration electricity storage. SSE said it sees it as a positive step forward in the continuing development of its £1.5bn, 30 GWh Coire Glas pumped hydro storage project at Loch Lochy in Scotland. It hopes to make a final investment decision on the project in late 2025/early 2026, with a view to it operating in 2032.

The consultation relates to government’s plans to create a cap and floor mechanism for long-term storage projects, to guarantee revenue if profits fall below an agreed (as yet unspecified) level, and a cap to return ‘some or all’ profits to consumers should prices rise above another agreed level.  

In late February, SSE Chief Executive Alistair Phillips-Davies explained to New Energy World what the company was looking for in a cap and floor deal. He said: ‘A number of years ago Ofgem consulted around interconnectors, and attracted just over 10,000 MW of interconnectors into the UK on the back of a capital floor structure. So we have simply been seeking for a number of years now to implement that regime for Coire Glas, because essentially, a pumped storage asset looks very much like an interconnector… And then can we establish a sensible price for the for the capital floor, so that so that we lower the cost of capital to build the asset?’

Although he said that SSE did not have a particular figure in mind for a cap and floor price at the moment, he added: ‘I think our number would be higher today than it would have been three years ago.’

He continued: ‘The government should have contracted for more assets more generally, whether it was in [contracts for difference allocation rounds] AR3, AR4 or whatever, a number of years ago, because prices have been pushed up by two things. One is supply chain costs. And secondly, interest rates and general cost of capital – returns on capital – that people require.’

Supporting the UK electricity grid

Meanwhile, a number of new initiatives have been announced this past week, aimed at supporting UK grid stability.  

NatPower UK has announced £10bn of clean energy investment to develop what it claims will be the largest portfolio of battery storage in the country (60 GWh), with £600mn of investment earmarked for the development of substations to help overcome grid bottlenecks and connection delays.

The company plans to bring three large-scale battery projects through planning in 2024, followed by 10 further projects in 2025. This has the potential to meet 15–20% of the energy storage needs of the UK by 2040 (around 80 GW).

In other news, UK Power Networks’ Distribution System Operator (DSO) claims to have become the first network in the country to offer a day-ahead flexibility product at distribution level. The move comes after a successful trial in the east of England and aims to ‘transform the flexibility marketplace, opening up more opportunities for electricity providers and supporting green energy’.

The introduction of the day-ahead product will see mini-tenders run daily to provide services for the following day, alongside the current twice-yearly flex tenders. The mini-tenders allow flexibility providers to offer a more informed view of their availability, offering new commercial opportunities and meaning they can co-ordinate their activity providing services in other places such as wholesale markets and ancillary services. The new product enables flexibility providers to help manage peaks in supply and demand by committing to changes in their behaviour the day before delivery.

In related news, clean energy company Enviromena reports that Blackfinch Energy’s Horsey Levels solar farm in Somerset became the first to be come online significantly ahead of its original planned connection date, after National Grid introduced changes to speed up connections late last year. The project is expected to have an annual energy yield of 27,550 MWh and will avoid over 5,000 t/y of CO₂.

Technological innovation

Lastly, researchers from the University of Birmingham have filed patent applications covering two novel ways of preventing threats to grid stability, focusing on the technological challenges of power system frequency control and forced oscillations (FO), which can cause widespread disruption over entire power grids.