Scotland has accumulated 32.8 gigawatts of proposed battery-storage capacity in its planning pipeline, making batteries the largest single technology awaiting development in the country’s renewable-energy system.
Most of those batteries do not yet exist.
Some have planning permission, some remain applications, some have secured places in the electricity-grid connection system and others may never be built. Against that background, Britain’s energy regulator is considering a new financial requirement intended to force developers to decide earlier which battery projects they are actually prepared to finance.
Ofgem opened a consultation on 17 September on an Oversubscribed Technologies Commitment Fee, known within the electricity industry as CMP470. It is currently minded to approve the proposal, but no final decision has been made and the consultation remains open until 1 October.
The proposed mechanism begins with a relatively simple problem. Britain now has far more battery projects holding prospective grid connections than its current energy plans expect the country to need.
Approximately 7GW of battery storage is already operating across Great Britain. Another 83GW has reached what the reformed connection system calls Gate 2.
Gate 2 does not mean that a battery has been built. It means the project has passed far enough through the new grid process to have, or qualify for, a firmer offer identifying where and when it could connect to the electricity network.
Together, the operating and Gate 2 projects amount to about 90GW.
The current national planning range is 23GW to 27GW of battery storage by 2030 and 24GW to 29GW by 2035.
Ofgem is therefore dealing with a queue containing roughly three times the battery capacity at the upper end of what the system is presently expected to require.
Scotland’s Battery Pipeline Is Much Larger Than Its Existing Fleet
The Scottish figures illustrate the difference between what is proposed and what is actually operating.
At the end of March 2026, Scotland had 1,583MW of electricity-storage capacity in operation. Of that, 843MW came from 22 battery projects and 740MW from Scotland’s two pumped-storage hydro schemes.
The planning pipeline was on another scale.
Scottish Government statistics recorded 32.8GW of battery projects at various stages of the planning process, within a wider 41.8GW electricity-storage pipeline.
Battery storage alone therefore represented more proposed capacity than either onshore wind, at 18.7GW, or offshore wind, at 17.3GW.
Those figures cannot be compared directly with Ofgem’s 83GW Gate 2 figure. The Scottish number comes from the planning system; the Ofgem number comes from the grid-connections system. A project can appear in one before reaching the equivalent stage in the other.
They nevertheless describe the same development boom from different directions: developers have been pursuing considerably more battery capacity than is likely to reach construction under the present energy pathway.
Why So Many Batteries Reached the Grid Queue
Britain has already attempted to clear its electricity-connections backlog.
For years, projects largely entered the queue according to when they applied. As applications multiplied, hundreds of gigawatts of wind, solar, batteries and other developments accumulated connection dates extending many years into the future.
The replacement system was intended to prioritise projects that were both sufficiently developed and considered necessary for the future electricity system.
Existing projects complicated the transition.
When the reforms were introduced, protection was given to developments that had already made substantial progress. Depending on their circumstances, that could include projects with planning progress, commitments under electricity-market arrangements or relatively near connection dates.
Battery developments were particularly well placed to satisfy some of those tests because they can often progress through planning more quickly than large generating projects.
The result was that the protections admitted considerably more battery capacity to Gate 2 than the national capacity pathway required.
Ofgem’s impact assessment records that 58 per cent of battery capacity within the relevant population has either not yet reached the point at which substantial cancellation liabilities begin or otherwise carries no significant securities or liabilities. Only 16 per cent has both passed that point and obtained planning consent.
The regulator’s concern is therefore not simply that the queue is large. It is that some developers can retain valuable future connection positions for several years while committing comparatively little money to them.
The Proposed Test Is Financial
CMP470 would not ask regulators to determine which battery design is technically best or which site would be most useful to Scotland.
Instead, it would increase the financial commitment required to continue holding a grid position when a technology becomes heavily oversubscribed.
The proposal would establish a minimum level of financial security or cancellation liability beginning at £3,000 for every megawatt of project capacity.
If excessive capacity remained in the queue, the minimum could rise first to £5,000 per MW and then in £5,000 steps at subsequent six-month reviews, reaching a maximum of £25,000 per MW.
A 100MW battery would therefore correspond to a minimum commitment of £300,000 at the starting level and £2.5 million at the maximum.
That does not mean every 100MW developer would receive a new £2.5 million bill.
Existing securities and liabilities would count towards the minimum. A project already providing sufficient financial security would not have to duplicate it. Security could also take forms such as guarantees rather than necessarily requiring the entire amount to be handed over as cash.
The mechanism would matter most to projects currently holding relatively inexpensive connection positions.
Ofgem found that half of the battery projects it examined had posted securities below £800 per MW and carried liabilities below £1,500 per MW.
For projects still several years from construction, the proposed floor could therefore produce a substantially earlier financial decision.
Why Ofgem Wants That Decision Earlier
Electricity networks are not planned only when a battery, wind farm or power station begins construction.
Network companies must work years ahead, determining where substations, transformers, cables and wider transmission reinforcements will be required.
A project with a firm connection position therefore affects decisions elsewhere in the system even before its own site is built.
If a battery developer holds a connection for years and eventually withdraws, some of the planning and engineering undertaken around that expected connection may no longer be required. Staff and supply-chain capacity can also have been committed to a project that never reaches operation.
Ofgem estimates approximately £460 million of outstanding potential network-inefficiency exposure across the relevant battery queue.
It is not a bill already incurred and it is not an estimate of what Scottish consumers will pay. The regulator constructed the figure from network-cost assumptions to measure the potential exposure created when projects leave after network planning has advanced.
Ofgem itself cautions that the calculation carries substantial uncertainty. It does not have enough information to predict how many developers would actually withdraw if CMP470 were introduced, and network costs differ considerably by location.
There is also a reverse risk. Batteries can sometimes reduce the need for network reinforcement by storing electricity where the network is congested. Removing the wrong project could therefore leave a network underprovided rather than overbuilt.
A Financial Test Does Not Necessarily Select the Best Battery
The principal objection to CMP470 is contained within the mechanism itself.
Money is being used as a proxy for commitment.
That can identify developers unwilling to place further capital behind a project. It cannot establish by itself whether one battery is more useful to the electricity system than another.
Ofgem’s own impact assessment recognises the possibility that higher security requirements could favour developers with greater access to liquidity rather than projects producing the greatest consumer value. It also identifies a risk to competition if smaller businesses find it more difficult to finance the requirement.
External analysis reaches a similar point.
Energy lawyers at Dentons have described the proposed amounts as relatively small compared with the total cost of constructing a completed battery, but potentially significant for a project that has not yet raised construction finance. Their analysis also notes that larger developers with portfolios and stronger balance sheets may find the requirement easier to absorb than smaller competitors.
Battery developer Root-Power challenged the use of an escalating charge as the sole mechanism during the formal industry process. It proposed allowing more time for the newly reformed queue to settle before the additional commitment took effect, arguing that this could avoid projects being forced out before developers had enough information to make final investment decisions.
Its proposed delay was not supported by a majority of the working group. Other participants argued that waiting longer would leave the current oversubscription unresolved and prolong uncertainty for transmission planners.
Another alternative proposed a much smaller one-off security payment, refundable once a project entered operation. That was also questioned on the grounds that it might be too low to cause developers to surrender unwanted connections.
The process has therefore exposed two competing risks: leaving weak projects in the queue for too long, and using access to finance to remove projects before their eventual value is known.
Hunterston Shows What a Fully Financed Project Looks Like
One Scottish battery has moved beyond much of that uncertainty.
Revera Energy announced on 23 September that it had reached financial close on its 400MW/800MWh Hunterston battery in North Ayrshire and had authorised construction to begin.
The project has senior debt from Santander, Barclays, Commonwealth Bank of Australia and NatWest, battery equipment contracted from Sungrow and commercial arrangements with BP and Danske Commodities.
Commercial operation is expected in the third quarter of 2028.
Hunterston sits north of the B6 transmission boundary, the part of the high-voltage network across which electricity moves between Scotland and England. That boundary is one of the points at which the volume of Scottish generation can exceed the network’s ability to move it south.
A battery on the northern side can charge when electricity is abundant and release energy at another time, although its actual value will depend on how it operates within electricity markets and network conditions.
Hunterston has therefore reached a very different stage from a project whose principal assets are planning rights and a future grid position. Banks and investors have committed money, major contracts have been signed and construction has been authorised.
Mey Shows the Earlier Stage
The 300MW Mey BESS project in Caithness illustrates another part of Scotland’s development pipeline.
Scottish Ministers granted the project consent in January. Its proposed four-hour configuration would provide 1,200MWh of storage.
Developer Ampeak Energy has said it is working towards financial close in 2027 or 2028, with operation targeted for the end of 2029.
The project has therefore secured planning consent but remains in the period between development and construction finance.
Earlier company disclosures said Mey benefited from protected status under the connections reform process. Public information does not yet establish exactly what additional CMP470 security Mey itself would ultimately have to provide, and Ampeak has not said the proposed rule threatens the project.
Its scale nevertheless shows how the arithmetic changes for a development before financial close.
For a 300MW project, a £3,000-per-MW security floor corresponds to £900,000. At £25,000 per MW it corresponds to £7.5 million. Existing securities would be deducted from any requirement, so those figures are not forecasts of what Mey would have to provide.
The issue for projects at this stage is not necessarily whether the ultimate battery can support such sums once financed. It is whether developers want to tie up additional financial capacity while land, grid, contracts, technology and construction finance are still being assembled.
It Is Not Yet Possible to Identify Every Scottish Project in the Queue
There is another limitation in assessing the consequences for Scotland.
The public grid registers have not caught up with the reform programme.
Energy-market analyst Modo Energy examined the 83.2GW Gate 2 battery total in September and found that the publicly available registers did not identify the complete population behind it. NESO has published aggregate capacity by area, while individual projects appear in the register only as new offers are accepted.
That means developers know the position of their own projects and NESO knows the complete queue, but an outside observer cannot yet reliably take Scotland’s 32.8GW planning pipeline and mark every project as inside or outside CMP470.
It also makes it impossible at present to state how much of Scotland’s planning pipeline will disappear because of the proposed financial requirement.
Natural attrition would have occurred in any event. Some projects will fail to secure finance, some will lose commercial appeal as more batteries enter the market, some may change capacity or technology and others will be built.
Ofgem expects that market forces would eventually reduce the queue even without CMP470. Its case for intervention is that this would happen too slowly for network companies making investment decisions now.
The regulator also acknowledges that it cannot predict how many projects the proposed financial requirement would remove.
A Consultation, Not Yet a Charge
Ofgem’s current document is a minded-to decision rather than a final determination.
The regulator is consulting on the original CMP470 proposal and alternative versions developed during the industry process. It has said the original form currently provides what it considers the strongest balance between clearing the queue, protecting consumers and maintaining an investable connections system.
Responses close at 5pm on 1 October.
Ofgem’s consultation timetable gives no fixed date for the final decision, describing the outcome as to be confirmed. The exact obligations faced by Scottish developers will therefore depend on the form of CMP470, if any, that the regulator ultimately approves.
Sources
Energy Statistics for Scotland – Q1 2026 — Scottish Government, 30 June 2026.
https://www.gov.scot/publications/energy-statistics-for-scotland-q1-2026/
Connection and Use of System Code CMP470: Introducing an Oversubscribed Technologies Commitment Fee — Minded-to Consultation — Ofgem, 17 September 2026.
https://www.ofgem.gov.uk/consultation/connection-and-use-system-code-cusc-cmp470-introducing-oversubscribed-technologies-commitment-fee-otcf
CMP470 – Introducing an Oversubscribed Technology Fee: Initial Impact Assessment — Ofgem, 17 September 2026.
https://www.ofgem.gov.uk/sites/default/files/2026-09/CMP470-Interim-Impact-Assessment.pdf
CMP470: Final Modification Report — National Energy System Operator, 14 July 2026.
https://www.neso.energy/industry-information/codes/cusc/modifications/cmp470-introducing-oversubscribed-technologies-commitment-fee
CMP470: Code Administrator Consultation — National Energy System Operator, 23 June 2026.
https://www.neso.energy/document/383551/download
Reviewing the GB battery connections queue: how much of the 83 GW can we see? — Modo Energy, September 2026.
https://modoenergy.com/research/English/gb-connections-queue-bess-gate-2-visibility-august-2026-battery-energy-storage-cmp470-ldes
Still “too many batteries” in the GB connections queue: first steps on CMP470 — Dentons, 1 May 2026.
https://www.dentons.com/en/insights/articles/2026/may/1/still-too-many-batteries-in-the-gb-connections-queue
Mey BESS Consent — Ampeak Energy, 19 January 2026.
https://ampeak.energy/mey-bess-consent/
Revera Energy Achieves Financial Close and Issues NTP on Hunterston BESS — Revera Energy, 23 September 2026.
https://revera.energy/news/fc-ntp-hunterston
Scottish Boundaries — National Energy System Operator, accessed 28 September 2026.
https://www.neso.energy/publications/electricity-ten-year-statement-etys/electricity-transmission-network-requirements/scottish-boundaries
