Chapter 4: Long-duration energy storage in context
110.This chapter will include a brief discussion of some of the complementary solutions that can be deployed alongside long-duration energy storage, as well as a brief outline of the barriers to and context for its deployment, as well key actors in the energy system, and decisions that need to be made in the next 1–3 years.
Planning and regulatory systems
Connecting projects to the grid
111.The Committee heard from projects that had won funding from the Government’s Longer Duration Energy Storage Demonstration (LODES) competition.175 Alongside the commercial pathway, they identified other barriers: Jim Isherwood, from io Consulting, who worked on a LODES-winning project to develop a 100 MW advanced compressed air energy storage facility, told us “The grid connection offer for our project was November 2037.”176 We were told “there is a tremendous queue of applications, and the sheer number … has almost overwhelmed the process for National Grid.”177 Ita Kettleborough, Director at the Energy Transitions Commission, explained that “the grid processing queue was developed in a world where there might be two, three or four major thermal plants a year. Now, the ESO is receiving around 1,600 applications a year.”178 She set out that there were more than twice as many projects in the queue as the UK would actually need. David Gray stressed the importance of “a way to prioritise the queue.”179
112.Mr Isherwood suggested that the ESO treats energy storage projects in a similar way to other energy generation projects, despite the fact that it can “alleviate constraints” and “de-bottleneck” the grid, but that appreciating this would require “a holistic view of the system.”180 Officials from DESNZ explained that reforms announced by Ofgem will allow “the system operator to insert milestones in connection agreements” and prioritise projects that are ready to connect, while terminating projects that have stalled.181 The Committee also welcomed the recent publication of the Connection Action Plan.182
113.We heard from would-be long-duration energy storage project developers that connecting to the grid is a barrier that can prove fatal to projects. The Committee welcomes the recent announcement that Ofgem is reforming the queue to remove non-viable projects, as well as the reforms proposed in the Connection Action Plan. This will be critical to ensuring a pipeline of projects can be developed in time.
114.Ofgem and the ESO should reduce the grid connection queue urgently and speed up timelines to connect projects to the grid. They should publish updates on how the reforms are progressing reducing the queue of proposed projects. They should consider prioritising storage projects for accessing the queue given their additional benefits such as alleviating grid constraints as well as acting as flexible generation.
Obtaining planning permission for energy storage
115.Many witnesses highlighted the planning framework as a major obstacle to storage projects. David Gray mentioned a project developing a natural gas storage site in north-West England during which he was “absolutely staggered at the extent of local resistance for a facility that, once built, would be pretty well invisible. Essentially, it was an objection to any development on the rural landscape. That is a major blockage to most large-scale energy projects.”183 The ESO’s Claire Dykta agreed, telling us that “a big blocker in any infrastructure build over the next 10 years will be the planning laws. They need to be reformed, otherwise there is a big risk to the delivery of even existing technology, never mind new technologies, by the mid-2030s.”184
116.Mr Isherwood told us that “having to go through the Development Consent Order (DCO) route for planning applications … would be a long-winded process. It would push our development timeframe to five to seven years before we [could] take an investment decision.”185 This is against a background in which, as Martin Scargill told us, “if we just go with the Natural Infrastructure Commission recommendation of eight terawatt hours by 2035, that is as many salt caverns to be built in the next 12 years as have ever been built in the UK.”186
117.It is not clear that the planning system is ready for Net Zero; Ita Kettleborough said that a “strategic vision” was needed for planning and permitting, especially as the current system “has been operating for the last 30 or 40 years [and] reasonably assumed a steady state, but our electricity usage in the UK has been declining, not doubling.”187 Energy UK told us that “current barriers to hydrogen storage include the lack of a licensing route for onshore hydrogen storage.”188 Ørsted told us that: “It is not clear how LDES technologies will be defined in the planning regime and whether the system and energy security benefits will be treated in the same way as renewable generation under the Nationally Significant Infrastructure Project definition.”189
118.Nick Winser was more optimistic. He told us that “although people find that planning process quite difficult, it is fundamentally sound.”190 He suggested that a Strategic Spatial Energy Plan (see later in this chapter) would help “inform the Planning Inspectorate’s view” of applications and ensure that a “broader political, economic, and engineering rationale” is laid out.191 His Electricity Network Commissioner’s report concluded that the current timescales for completing infrastructure projects could be halved: “it currently seems to be 14 years … We can drive it down to seven, so that would still fit into the timescales we have.”192 The Minister set out some ongoing reforms to planning, including “updated national policy statements” and reforms to the Nationally Significant Infrastructure Projects planning system.193
119.We have heard that obtaining planning permission for energy storage facilities can be difficult and add significantly to timelines. It is not clear that the planning system has distinct guidance for energy storage facilities as opposed to energy generation. There currently is no regulatory licensing regime for the onshore storage of hydrogen, so developers need additional guidance from Government.
120.The planning system must be reformed and sufficiently resourced to deal with the additional strain on it from new energy projects. It must recognise storage for its own value for energy system resilience by the end of 2024. The Government, working closely with Ofgem, should identify and set out the regulatory barriers to storage project developments and explain what actions it will take to address them. This should include more detailed guidance for developers on navigating the planning system, as well as clarifying how onshore storage of hydrogen will be regulated and licensed.
Skills for net zero
121.Concern about skills gaps and skills shortages for Net Zero are widespread.194 We heard contrasting views on the availability of the necessary skills for the Net Zero transition. For example, for battery storage projects, Professor Thomas, CEO of the Faraday Institution, told us of a blueprint for the National Electrification Skills Framework and Forum (NESFF), developed in collaboration with WMG and the High Value Manufacturing Catapult, which aims to provide “the suite of skills required from level 3 right up to level 8, so PhD skills at the top level. This framework is envisioned to extend beyond passenger automotive to encompass various transport modes as well as stationary energy storage solutions.”195
122.David Surplus, whose company B9 Energy was awarded LODES funding to develop a hydrogen storage project, said that the disciplines needed were “the electrical power sector, the oil and gas sector, the chemical industry, and … the water industry”, adding that “the skills are all there and the academic institutions are happy enough that the courses and curriculums can be put together for the people we would need.”196 Martin Scargill echoed this, saying that these skills were “an extension of what we have relied on for decades in the oil and gas industry. … The skills are very much the same. We just need more of them”.197
123.However, Daniel Murrant told us that “even if we wanted to roll out a hydrogen network tomorrow, we do not have the skills to do that as quickly as we would like”.198 Simon Virley identified the skills shortfall as a “major barrier”, saying that “we need a major step up in skills and training to create the number of electrical engineers, hydrogen engineers and others who will be needed.”199
124.Professor Bruce noted that this will affect the investment decisions of firms: “It is no good simply asking businesses to bid to operate salt caverns. Unless they know that … skilled people will be there to operate these things, it does not make a sensible business case.”200 Tim Lord suggested that there was a reciprocal relationship between investment decisions and skills provision, stating that “you cannot do this only by pushing the supply side; you have to have the pipeline of projects and credible investment instruments that those projects might get built. That will then create the incentives for private sector developers and investors to invest in skills to get them built.”201
125.David Gray told us that part of the challenge with respect to skills was identifying the specific skills shortages: whilst “we have a range of areas where we know that we will have locally specific jobs … there is a whole range of jobs where perhaps people do not fully understand the vision and the connection of those roles with meeting the decarbonisation challenge that we face.”202
126.As with many other Net Zero ambitions, the availability of relevant skills, including all types of engineers and particularly those with experience of hydrogen, will be a barrier to scaling up technologies.
127.The Government should work with industry to determine and set out an assessment and estimate of the numbers of skilled individuals that will be needed to deliver on its hydrogen targets, and across which professions, and work with industry to fund training and retraining programmes accordingly. Training skilled individuals has the longest lead time and so needs to be happening now if projects are to scale up.
Minimising the need for long-duration energy storage
128.As discussed in chapter 3, there is a range of estimates for how much storage will be needed on a decarbonised grid. Michael Liebreich explained that there are “other ways in which we can balance things” and we are likely to “do those first because they are cheaper”, especially “under … 48 hours”, citing demand flexibility, thermal storage, and interconnectors.203
129.Long- and medium-duration energy storage for the electricity system will be critical for a fully decarbonised grid, but it will not always be the cheapest option: energy efficiency, thermal energy storage, demand-side response and interconnectors can minimise our reliance on energy storage, especially on shorter timescales.
Demand flexibility
130.Rachel Hay said that a strategy for a decarbonised electricity system by 2035 should cover “the full range of low-carbon flexibility options [including] demand flexibility.”204 Ita Kettleborough explained that “hot water storage in houses” was an example of demand that could be shifted to hours with higher generation.205 Caroline Still said that “car batteries [are] a form of demand-side flexibility” that “can provide a reduction in peak demand … through smart charging.”206
131.Some demand-side response projects, such as the Demand Flexibility Service (DFS), are already underway.207 In the DFS, the ESO publishes an indication of need for demand to be reduced between certain hours the next day or later the same day. Participation depends on having a smart meter and an energy supplier being part of the scheme.
132.To incentivise consumers to use energy flexibly, Tom Lowe of Thermal Storage UK told us we need “smart time-of-use tariffs” and to “encourage” or “mandate” energy retailers to offer them. To make these viable, he said “we need to complete the smart meter rollout [and] move to market-wide half-hourly settlement, which we are expecting in 2026.”208 This would allow tariffs to change with the time of day and thereby respond to supply and demand.
133.Michael Liebreich set out a scenario for more extreme demand-side management—during extremes of low wind and solar generation like the “dark doldrums”, when there is an extended period of low wind speeds in winter, “you can also switch off the electrolysers, refineries … industrial uses of power that can be switched off at large scale when you need to.”209 Claire Dykta explained that, with appropriate compensation, “heavy, intensive industrial users could change their processes” to use power at optimum times. This could reduce peaks in demand and hence the amount of storage generating capacity needed.210
134.Flexible demand can help to smooth out variations across hours and days. In extreme cases of low generation, it may help balance the system if electrified industries shut down temporarily to reduce peak demand, but it does not seem that mechanisms for this have been explored. However, there could also be demand-side risks, such as a “run on the plugs”, for example if a much higher than normal number of drivers decide to charge their electric vehicles simultaneously due to concerns over supply.
135.The Government should build on initiatives from the National Grid Energy System Operator like the Demand Flexibility Service, expanding them and making them permanent. This should involve a robust programme of consumer research to ensure people who provide flexibility are incentivised, rewarded, and protected appropriately, but also to understand any potential flaws in how the system works in practice in a range of circumstances. The Government should support the roll-out of market-wide half-hourly settlement, which will help energy companies offer electricity tariffs that encourage people to operate appliances flexibly. It should explore the potential for more serious demand-side interventions where supply is extremely limited.
Interconnectors
136.Electricity network interconnectors have been successfully expanded to support the grid and allow for import and export.211 Simon Virley said that “we have seen cap and floor work for interconnectors … [with] long lead times, high capital expenditure requirements, and an uncertain operating environment.”212 However, Daniel Murrant noted that “they are very important, but … European weather cycles are broadly similar to ours and there are potentially also political issues” with relying on them instead of domestic long-duration energy storage.213
137.We heard concerns from Statera Energy that “since leaving the European Union, the GB market has decoupled from the EU market”, resulting in “explicit trading” which is “far less efficient.”214 Correlated weather cycles across Europe means that renewable supply from wind is likely to be low across the continent at the same time, and so we cannot rely on importing from neighbours. Michael Liebreich set out the possibility of intercontinental interconnectors “further than Europe … to places that are north-south and so have very different weather patterns, or east-west and so have very different time zones”.215
138.Interconnectors with other countries can reduce, but not eliminate, the need for energy storage and curtailment on the grid and could allow us to export our storage capacity. There are security and political risks associated with over-reliance on interconnectors, especially in an energy crisis which is likely to be Europe-wide. The Government’s ambition to more than double interconnector capacity by 2030 is welcome and successful deployment so far demonstrates the value of cap-and-floor subsidies.
139.The Government should pursue expansion of GB interconnectors as part of its energy security strategy, ensuring we can trade efficiently with the EU market. It should explore the potential for interconnectors that could help manage seasonal demand and mitigate risks from weather systems that extend across Northern Europe, by connecting further afield with EU Member States, such as Southern European States, as well as the Middle East and North Africa.
Thermal storage
140.Tom Lowe of Thermal Storage UK said that thermal storage has “a role in the 24-hour use case” to “reduce … peak demand”.216 He also explained that “if we electrify heating, we will be putting in thermal stores with heat pumps anyway. You may as well use them as much as possible for grid management”217 whereby electrified heating is used to heat water or thermal stores at off-peak times to release heat later.
141.Mr Lowe set out some examples of pilot projects, including one for “industrial heat processes”, which have been funded by Government.218 However, he also highlighted some aspects of Government policy where the flexibility provided by thermal stores was not fully considered, including VAT, energy performance certificates, and inclusion in the boiler upgrade scheme.219
142.Thermal energy storage, both domestically and as part of heat networks, could play a significant role. It can shift peak demand times and help with the integration of electrified heating such as heat pumps. A few small-scale projects have been supported through the Longer Duration Energy Storage Demonstration Programme, but we encourage the Government to do more to support thermal energy storage.
143.Ofgem and the Future System Operator should identify ways of incentivising businesses and households to provide flexible heating that can support the grid. Thermal storage and an assessment of flexibility should be included in existing policy mechanisms, such as Energy Performance Certificates, the Energy Saving Materials technology list for VAT relief, grants such as the Boiler Upgrade Scheme, and the Clean Heat Market Mechanism.
The roles of different actors in the energy system
144.Witnesses told us that one challenge is the number of organisations that have a potential role in delivering long-duration energy storage; the ESO’s Claire Dykta said that “there are lots of different bodies and, historically, the energy system has been quite siloed in how it thinks and how it operates.”220
145.Whilst there will be a number of issues that these organisations will need to address, we heard that the Future System Operator in particular will face a unique task of balancing supply and demand on the grid, requiring a greater degree of flexibility. Matt Harper set out the challenge:
“The difficulty is that the electric grid was constructed around a very centralised model with huge energy facilities. … We are now in a world where the grid is more decentralised. More of the assets that are coming out of the grid are not available on command. What the grid operators are struggling with is to maintain that same level of absolute low-cost reliable power in a world where they have less and less control over how those generating assets are operated.”221
146.Ms Dykta recognised that the FSO’s remit, powers and responsibilities needed to be clearly set out, telling us that “There is an awful lot of work going on … between … the electricity system operator, the government department and the regulator Ofgem to define the lines of responsibility and how things will move forward.” The Energy Bill will provide for certain duties; alongside this there will be a “more informal … advisory role that … provides advice to the Government on the development of policy.” 222
147.Nick Winser said that “a plan that all … stakeholders can focus on, well defined in terms of the responsibilities for its delivery and endorsement, will provide a focal point”.223 Dr David Joffe told us that “formalis[ing] the institutional responsibilities of the future system operator, Ofgem and the Government in delivering this system” was also one of the Climate Change Committee’s recommendations. It recommended that there should be “a Minister-led infrastructure delivery group to ensure that these things are moving forward.”224
148.Asked about the number of actors involved in the net zero transformation, DESNZ officials told us that
“the Government’s role is to set the policy direction. Ofgem is the independent regulator … and it makes decisions on business and investment plans. We see the future system operator as the whole-system planner, the operator of the electricity system and an expert adviser to the Government and Ofgem as the key decision-makers.”225
149.The Minister told us that “we are also developing a framework agreement that will set out the relationship between government as shareholder and the FSO, which we plan to publish shortly after designation” to provide more detail on governance questions.226
150.There are many actors with a role in delivering long-duration storage, from the Department of Energy Security and Net Zero, Ofgem, the proposed Future System Operator, energy companies, the electricity transmission network owners and so on. In particular, the FSO has a potentially difficult role in coordinating and balancing supply and demand on a grid that is larger, more complex, decentralised and variable than before. There is a need for an overall “guiding mind” with the authority to take decisions and coordinate actions.
151.The Government must ensure that stakeholder organisations coordinate their efforts, that responsibilities and remits are clearly delineated and foster a shared vision of how the future energy system should look and how to get there. The role and powers of the Future System Operator and the Secretary of State need to be clarified, especially with respect to ensuring resilience and security of energy supply, and the FSO needs to be appropriately empowered and resourced to fulfil its mandate.
Transmission networks and the Strategic Spatial Energy Plan
152.As well as connecting individual projects to the grid, strategic transmission network capacity is important. Ita Kettleborough explained that “Transmission and distribution become critically important when you have a renewable-dominated system, because where the wind blows best might not be where the consumption is. You have to move the electrons around more.”227 The Royal Society quoted a National Grid estimate that Net Zero would require £100 billion in investment between now and 2050 to enlarge and strengthen the transmission grid.228 The Government set out in its Transmission Acceleration Action Plan its response to the recommendations made by the Electricity Networks Commissioner to halve the timeline for constructing strategic transmission infrastructure from 14 years to 7 years.229
153.Timothy Armitage said “We need to co-locate our storage effectively with hydrogen production and demand … [we need] an integrated system with overall master planning and a direction of travel that everybody can buy into.”230 Dr David Joffe described the need for decisions to be made in hydrogen infrastructure as well: “we have a pretty good idea of where the hydrogen storage might be, because only certain geologies are suitable to host salt caverns. But in order to make the infrastructure investments, we need to know at a transmission level what we are joining up.”231
154.Transportation and transmission networks for hydrogen and electricity will need to be substantially improved and expanded. There is a need for sensible coordination in the design of hydrogen and electricity systems. Co-locating electrolysers and hydrogen-to-power generation with storage seems the most efficient option, but this will require significant electricity transmission infrastructure connecting storage sites to generation and to the grid. Hydrogen pipelines could connect storage to planned hydrogen industrial hubs. Without some assurance around how transmission networks will evolve, it will be hard for investors to make large-scale investment decisions into storage.
155.The Electricity Networks Commissioner recommended that a Strategic Spatial Energy Plan (SSEP) should be developed (and regularly refreshed), that would translate high-level targets into specific volumes in specific locations.232 The Government said in its Transmission Acceleration Action Plan that it “broadly supports” the SSEP and “work has already begun”, and that “in early 2024, we will commission the Energy System Operator … to work with government to develop the SSEP”, and that “the first iteration of the plan will focus on power and hydrogen assets.”233
156.Witnesses supported a spatial plan; Emily Bourne explained that the plan was needed “to give that level of certainty, which does not exist at the moment” about energy policy, and said DESNZ was “working with Ofgem, the system operator and other departments to design that process” by which the plan would be developed.234
157.Nick Winser laid out further ways in which having an overall strategic plan would assist the energy system transformation: “A strategic plan will also help projects, both on the network and on storage, to go through the planning process… It will also enable us to look at whether we think we have the right market and regulatory signals in place to get each part of the plan delivered, mainly by private investment.”235
158.The Electricity System Operator warned of a “disjointed approach to spatial planning” without a clear strategy.236 Michael Liebreich said “the idea that the market will figure out energy choices does not work … having a strategy is a necessity” but that we must “make sure that the strategy does not obliterate price signals.”237 There is considerable urgency in finalising this plan: Dr David Joffe said that we need a plan “ideally yesterday or the day before” for “making strategic decisions across the energy system for these long lead-time investments.”238
159.Owen Bellamy of the Climate Change Committee described an SSEP as “a useful and a worthwhile addition” to an “overarching strategy.” However, he said it must be “done in a sequenced and co-ordinated way because there is a range of issues that only the Government can take strategic decisions on, and [the] planner … will not necessarily be able to”. He said that the process of planning needs to identify “strategic priorities” and the plan “needs to go down to the level where you can make infrastructure decisions”, so “at least regional and possibly down to the local level as well.”239
160.Nick Winser and Claire Dykta spoke of the Government “endorsing” the plan to ensure other actors took it seriously, although Mr Winser admitted that “there is a lot of debate to be had about what is meant by ‘endorse’”.240 When asked if the plan would have statutory weight, DESNZ’s Emily Bourne said it was being “actively considered.”241
161.The Minister told us that the Strategic Spatial Energy Plan will feed into future plans: it will “enable the creation of a transmission network blueprint in the centralised strategic network plan, which will be produced by the FSO.” He said that the SSEP would “define the optimal location, generation and infrastructure required to meet forecast demand and our 2050 targets” and that the FSO would “develop the SSEP using policy inputs and priorities provided by [the Government], including technology-specific targets, with oversight from the regulator.”242 The Minister did not commit to a specific date, but Emily Bourne said that “The aim is for the first strategic spatial energy plans to be produced in time to inform the centralised strategic network plan… in 2025–26.”243
162.On whether the plan should be statutory, the Minister said “we can look at whether we need to make it statutory or to bring in any specific enforcement or alignment with national policy statements and the like” in the case that “we do not think it can do its job simply through joint publication [and] consultation.”244
163.Ms Bourne said that in the “commission that we are developing at the moment, we are looking at the governance” for how a Strategic Spatial Energy Plan would be implemented.245 The Minister told us that “the democratically elected Government will need to approve this”, but he hoped the FSO’s report would have “enormous weight” and that there would be a “proper, grown-up, mature approach to make sure that we are on the same page.”246
164.There is an urgent need for key strategic decisions and investment into the transportation networks for both electricity and hydrogen. These network decisions should support the deployment of large-scale long-duration energy storage and a strategic energy reserve. These decisions should be communicated as part of the Strategic Spatial Energy Plan and delivered by a cross-departmental Ministerial Working Group, as currently exists for electricity network transmission infrastructure.
165.We welcome the commitment to develop a Strategic Spatial Energy Plan, which is critical for long duration energy storage, but details remain unclear. We are unclear about the level of detail—for example, whether the Plan will be at the regional level or identify major facilities—as well as who will take responsibility for delivering on the plan once it has been developed by the Future System Operator. It is also unclear whether the plan will be given a statutory basis and how it will fit within the planning system. There is a risk that the Future System Operator develops a plan with substantial implications for national infrastructure and public expenditure, requiring coordinated action from many actors in the energy system, which the Government does not fully commit to, and so there is a lack of follow-through. ‘Endorsement’ of the plan may not be enough.
166.The Strategic Spatial Energy Plan should include locations for long-duration energy storage and the supporting infrastructure. It must include provisions that support the Government’s targets for hydrogen, and address the need for long-duration energy storage on the grid and a strategic reserve. It should be developed iteratively, and updated at regular intervals, with close collaboration between the FSO, Ofgem and the Government.
167.The Future System Operator needs to be sufficiently empowered and resourced to develop a credible plan. As it does so, it must identify the key strategic, infrastructure and investment decisions that the plan entails. These decisions must then be made swiftly by the Government, which must then commit to ensure every actor in the system is working to deliver on them. Ofgem should endorse it in line with its Net Zero mandate.
168.We urge the Government to publish timelines for developing the plan and details of what it will contain as soon as possible. It should consider whether a statutory basis for the plan is needed to ensure it is carried out.
175 Department for Energy Security and Net Zero and Department for Business, Energy and Industrial Strategy, ‘Longer Duration Energy Storage Demonstration (LODES) competition (closed to applications)’, 12 April 2023: https://www.gov.uk/government/collections/longer-duration-energy-storage-demonstration-lodes-competition [accessed 10 January 2024]
181 Q 96 (Emily Bourne) and Ofgem, ‘Ofgem announces tough new policy to clear ‘zombie projects’ and cut waiting time for energy grid connection’ (13 November 2023): https://www.ofgem.gov.uk/publications/ofgem-announces-tough-new-policy-clear-zombie-projects-and-cut-waiting-time-energy-grid-connection [accessed 10 January 2024]
182 Department for Energy Security and Net Zero, Connections Action Plan: Speeding up connections to the electricity network across Great Britain (November 2023): https://assets.publishing.service.gov.uk/media/655dd873d03a8d001207fe56/connections-action-plan.pdf [accessed 10 January 2024]
185 Q 34 (Jim Isherwood). Development Consent Orders (DCO) are the means of obtaining permission to construct and maintain developments categorised as Nationally Significant Infrastructure Projects.
194 Parliamentary Office of Science and Technology, Green skills in education and employment, POSTnote 711, January 2024
203 Q 68 (Michael Liebreich) he was clear in this answer that in his opinion alternatives do not eliminate the need for on the order of 20 TWh of long-duration storage.
207 ESO, ‘Demand Flexibility Service: What is the Demand Flexibility Service’: https://www.nationalgrideso.com/industry-information/balancing-services/demand-flexibility-service-dfs [accessed 10 January 2024]
210 Q 56 (Claire Dykta) and written evidence from National Grid Electricity System Operator (LES0032)
211 By 2024 interconnectors will have a capacity of 7.8 GW (15% of UK demand) and in 2022 they supplied around 13.7 TWh of electricity to the UK. See National Grid, ‘What are electricity interconnectors?’: https://www.nationalgrid.com/stories/energy-explained/what-are-electricity-interconnectors [accessed 10 January 2024]. This capacity has trebled since 2010, see Department for Business, Energy and Industrial Strategy, Electricity interconnectors in the UK since 2010 (June 2022): https://assets.publishing.service.gov.uk/media/62bb2816d3bf7f662753cfa8/Electricity_interconnectors_in_the_UK_since_2010.pdf [accessed 10 January 2024]
228 The Royal Society estimated 100 terawatt-hours (TWh) of storage would be needed. See Royal Society, Large Scale electricity storage (September 2023), box 1: https://royalsociety.org/-/media/policy/projects/large-scale-electricity-storage/Large-scale-electricity-storage-report.pdf [accessed 10 January 2024]
229 Department for Energy Security and Net Zero, Transmission Acceleration Action Plan (November 2023): https://assets.publishing.service.gov.uk/media/65646bd31fd90c0013ac3bd8/transmission-acceleration-action-plan.pdf [accessed 10 January 2024]
232 Catapult, Electricity Networks Commissioner—Companion Report Findings and Recommendations (June 2024): https://assets.publishing.service.gov.uk/media/64c8e85219f5622360f3c0ee/electricity-networks-commissioner-companion-report.pdf [accessed 10 January 2024]
233 Department for Energy Security and Net Zero, Transmission Acceleration Action Plan (November 2023): https://assets.publishing.service.gov.uk/media/65646bd31fd90c0013ac3bd8/transmission-acceleration-action-plan.pdf [accessed 10 January 2024]
244 Q 117 and Q 118 (Graham Stuart MP)
247 Written evidence from Professor Seamus Garvey, University of Nottingham (LES0002), Form Energy (LES0018) and National Grid Electricity System Operator (LES0032)
258 Department for Business, Energy and Industrial Strategy, Review of Electricity Market Arrangements (July 2022): https://assets.publishing.service.gov.uk/media/62fa281ee90e076cfe3649ed/review-electricity-market-arrangements.pdf [accessed 10 January 2024] and Parliamentary Office of Science and Technology, Electricity Market Reform, POSTnote 694, May 2023
259 Department for Business, Energy and Industrial Strategy, ‘UK launches biggest electricity market reform in a generation’ (18 July 2022): https://www.gov.uk/government/news/uk-launches-biggest-electricity-market-reform-in-a-generation [accessed 10 January 2024]
261 Department for Energy Security and Net Zero, Review of Electricity Market Arrangements: Summary of responses to consultation (2023): https://assets.publishing.service.gov.uk/media/640226048fa8f527fe30dbba/review_of_electricity_market_arrangements_summary_of_responses.pdf [accessed 10 January 2024)