In this week’s Charging Forward, SSE has submitted plans for its Sloy pumped storage hydro project in Scotland, OnPath Energy has secured consent for a West Lothian battery energy storage (BESS) project and UK thermal energy storage developer Caldera secured a £10 million investment.

This week’s headlines:

• SSE submits plans for Sloy pumped storage hydro conversion
• Gilkes Energy secures consent for Earba pumped storage hydro
• Ofgem launches long duration cap and floor
• Battery storage set to add £1.6bn to UK economy annually by 2035
• OnPath Energy gets nod for 200 MW West Lothian battery
• Root-Power secures consent for 50 MW Reading BESS
• Flexion Energy wins consent for Aberdeen BESS on appeal
• Brockwell Energy unveils 100 MW Selby BESS plans
• Invinity to develop its largest UK flow battery
• Caldera secures £10m investment in thermal storage tech
• ILI puts Scottish battery projects up for sale
• American asset manager acquires UK solar and battery storage developer
• International news: TotalEnergies invests in six German battery projects and Energy Vault secures $28m financing for hydrogen and BESS microgrid

SSE plans Sloy pumped storage hydro conversion

SSE Renewables has submitted a planning application to convert the Sloy hydropower station on the banks of Loch Lomond into a pumped storage hydro (PSH) scheme.

The company said the proposed development would have a pumping capacity of up to 100 MW and be capable of delivering up to 16 GWh of long duration energy storage.

Subject to approval from the Scottish government, SSE said it hopes to make a final investment decision (FID) on the project in late 2027.

If approved, the Sloy PSH scheme could be commissioned by the end of 2030, SSE said.

As part of the plans, SSE said it will also upgrade the existing turbines at the Sloy site to increase the generating output to 160 MW.

© Supplied by SSE Renewables

SSE said the Sloy conversion could support up to 70 jobs during the design, development and construction phases.

SSE Renewables director of hydro Robert Bryce said the Sloy project will “play an important role” in the UK government’s clean power by 2030 plans.

Bryce added that when complete, the Sloy PSH will provide firm, flexible renewable energy “for up to 100 hours non-stop at the flick of a switch”.

“The existing Sloy Power Station has been operational since 1950 and over the past seven decades has played a significant role in our energy system,” he said.

“The new proposals will ensure this remains an important asset for decades to come.”

Bryce argued that the scheme will provide an economic and employment boost to the local area and help balance the grid during times of peak demand.

Gilkes Energy secures consent for Earba PSH

Kendal-headquartered Gilkes Energy has received approval from the Scottish government for its 1.8 GW Earba PSH scheme.

Located between Newtonmore and Fort William, the project is the largest ever PSH scheme to gain approval in the UK, with up to 40,000 MWh of energy storage.

Gilkes Energy said Earba PSH “stands as a ground-breaking achievement” in the field of long duration energy storage (LDES), describing it as a “game changer” for the UK energy sector.

Earba PSH project director David Tomb explained that the “sheer scale” of the plans makes it a “landmark project with national significance”.

“To put this into perspective, it would require the construction of 400 typical lithium-ion battery storage systems (each with 50 MW capacity and 100 MWh of storage) to match the equivalent storage capacity of Earba,” Tomb said.

“That is a staggering amount, especially when you consider the footprint of these battery sites.”

With 22 hours of energy storage, Tomb said Earba will provide significant system benefits by reducing wind curtailment payments and cutting down on gas generation, resulting in lower emissions and a cleaner grid.

The planning application also includes proposals for two large-scale peatland and woodland restoration projects as part of efforts to enhance biodiversity in the area.

Gilkes Energy said the project will create around 500 on-site jobs during its six to seven year construction phase, providing a “catalyst for economic growth” in the region.

With the UK government introducing a cap and floor mechanism to support LDES projects, including PSH, Gilkes Energy said the Earba project is “well-positioned” to secure financing and development support.

Ofgem launches LDES cap and floor

UK electricity regulator Ofgem has opened its cap and floor investment support scheme for LDES projects for applications.

The revenue support scheme offers LDES developers a minimum revenue threshold to boost investor confidence, similar to the Contracts for Difference (CfD) scheme used to support renewable energy projects.

The scheme also includes a cap on profits, with excess revenues flowing back to UK consumers via their energy bills.

The cap and floor programme includes LDES technologies such as PSH, liquid air energy storage, compressed air energy storage and flow batteries, among others.

Ofgem director general for infrastructure Akshay Kaul said the cap and floor will create confidence for investors to build LDES “super-batteries”.

“For decades, hydro power has played an important role in our energy system and we expect it and a range of other storage technologies to make an even greater contribution to grid stability, with more projects ready to bid to play their part in this unprecedented investment in energy storage,” Kaul said.

“We have not built any new LDES in 40 years but today we are reversing that legacy by unlocking investment in this important technology to help build a clean, secure energy system for the future.”

Battery storage to add £1.6bn to UK economy

Solar Energy UK has released a report which estimates the battery storage sector could provide £1.6bn in gross value added (GVA) to the UK economy by 2035.

The figure is up from the estimated £600m GVA battery storage provided to the UK economy in 2024.

In total, the report estimates that utility-scale battery storage will provide £1bn GVA by 2035, alongside commercial (£400m) and residential (£185m) scale projects.

The BiGGAR Economics report also projects battery storage will support 13,900 jobs across the UK by 2035, up from 7,400 jobs in 2024.

© Supplied by Statkraft

The report assumes the UK will increase its battery storage capacity to 50 GW by 2035, up from the 7.5 GW capacity seen at the end of 2024.

Solar Energy UK director of policy and delivery Gemma Grimes said: “Growing renewable energy generation at pace, alongside the capacity to store it, is obviously of critical importance to meet the UK’s climate change goals.

“But beyond being cheap, flexible and low-carbon, the effects of solar and battery energy storage on the economy have played little part in public discourse to date.

“The report makes clear that the sectors are already a significant economic player, with their anticipated growth making them a massive stimulus within the next ten years.”

The report comes as data from Solar Media Market Research shows the UK has a total of 55.4 GW/117 GWh of approved battery storage projects in the pipeline.

OnPath Energy 200 MW West Lothian BESS

UK onshore renewable energy developer OnPath Energy has secured planning consent for a 200 MW BESS project in West Lothian, Scotland.

OnPath said the site, located at the Pond Industrial Estate near Bathgate, will have the capacity to meet peak electricity demands for around 240,000 average homes.

In total, the £130m Pond Flexible Energy Park is expected to support around 80 jobs during construction.

OnPath Energy sustainability developer Michael Newton said the project will deliver “significant” social and economic benefits to the local economy.

This includes over £1m in community benefits, Newton said.

Root-Power 50 MW Reading BESS

UK battery storage developer Root-Power has received planning permission for a 50 MW/100 MWh BESS project in Silchester, Reading.

Root-Power said the site will be able to power up to 100,000 over a two-hour period once fully operational.

The firm said it selected the Withy Place site due to its proximity to the Bramley substation.

© Supplied by Root-Power

The BESS project has a 2027 connection date, with construction expected to start in early 2026.

The Withy Place project is the sixth Root-Power BESS project to secure planning permission in 2025, following recent approvals in Lincolnshire and Dounreay.

Root-Power managing director Neil Brooks said the Withy Place project incorporated innovative solutions to mitigate noise and visual impacts on the greenbelt site.

“Our team have an impressive track record of finding suitable locations for battery storage schemes in the greenbelt, with Withy Place being our fourth greenbelt project to obtain planning permission in recent months,” Brooks said.

“With a 2027 connection date, this project will form a key part of our plans for the next few years.”

Flexion Energy wins Aberdeen BESS appeal

Flexion Energy has secured approval from the Scottish government for a BESS project in Aberdeen after local councillors initially refused the plans.

The company’s plans for the 40 MW BESS site in Cults received more than 100 objections from the local community, but the project will now go ahead.

Scottish government planning reporter Stephen Hall overturned Aberdeen City Council’s decision, saying he was “satisfied that there would be no significant long-term impacts on the environmental quality of the green belt”.

However, he imposed some conditions that must be met by the firm before work starts.

This includes a demonstration from the company on how the facility would be integrated into the surrounding area – such as which existing trees will be removed, where new trees will be placed, and details of the access road.

Brockwell Energy unveils 100 MW Selby BESS

Developer Brockwell Energy has unveiled plans for a 100 MW BESS project near Selby.

The New Oak Energy Storage project will be located near the A645, with Brockwell set to submit plans to North Yorkshire Council for approval.

Brockwell said selected the site due to its proximity to existing power lines and an agreed National Grid connection near the Drax power station.

Brockwell Energy head of project development Gary Bird said the project will play an important role in securing a “domestic green energy supply” if consented.

“We hope members of the local community will attend the event so that we can provide further details of our proposals, answer any questions and gather feedback,” Bird said.

However, the plans have already attracted criticism from local campaign group Halt.

Halt campaigner Pam Spreckley told the Local Democracy Reporting Service that she was “absolutely furious” about the New Oak plans, describing BESS projects as “dangerous and noisy”.

Invinity to develop its largest UK flow battery

Battery developer Invinity Energy Systems has reached an agreement with the UK government to build its largest ever vanadium flow battery (VFB) project.

The VFB BESS project, located in the south east of England, is part of the UK government’s longer duration energy storage (LODES) demonstration programme.

Under the deal, Invinity will develop, build, own and operate an up to 20.7 MWh vanadium flow battery system using the company’s VS3 vanadium flow batteries.

The VFB batteries will be produced at the company’s production site in Motherwell, with the Department for Energy Security and Net Zero (DESNZ) providing a grant between £7m and £10m towards the overall £20m cost of the project.

The project will also have co-located solar energy production, which will be developed separately by a third party.

© Mathew Perry/DCT Media

Inivinity expects construction to begin in the second half of 2025, with operations commencing in 2026.

Invinity chief executive Jonathan Marren said owning and operating the site will give it valuable data, which will enhance future commercial opportunities.

“Once operational in 2026, the asset should generate revenue and positive cash flow for the company and provide important benefits to the UK grid, allowing more low-cost, low-carbon renewable energy to be utilised, contributing to lower consumer bills as a result,” Marren added.

Confirmation of funding for the LODES project comes shortly after Invinity launched its next-generation Endurium flow battery in December.

Caldera secures £10m investment

UK thermal energy storage developer Caldera has secured a £10m investment from German industrial firm GEA.

Caldera develops industrial electric storage boilers which can store electricity in the form of heat that can be extracted on demand.

The boilers can be used to decarbonise industrial processes in a range of sectors including food manufacturing, dairy production, brewing and distilling.

GEA heating and refrigeration technologies division chief executive Kai Becker described Caldera’s technology as a “milestone”.

© Supplied by Caldera

“It bridges the gap between variable renewable electricity generation and industrial process heat demand and offers a scalable, economically viable alternative to fossil fuel boilers,” Becker said.

Caldera chief executive James Macnaghten said the £10m investment is a “strong endorsement” of the company’s technology.

“Having just started to sign early orders we know that we are on the right track,” he said.

“I believe that working with GEA and especially leveraging GEA’s vast experience will help deploy our storage boilers into even more companies… with the ultimate goal of reducing carbon emissions for the benefit of all.”

ILI puts Scottish battery projects up for sale

Intelligent Land Investments (ILI) has put five of its Scottish BESS developments up for sale.

The 350 MW project pipeline includes sites in the Highlands, North Ayrshire, Perth & Kinross, and West Lothian council areas.

The Hamilton-headquartered firm said all BESS sites have secured land rights, are either consented or due to obtain planning consent by May.

The projects have connection dates ranging from 2026 to 2028 and have either pre-qualified or a high-probability for NESO Gate 2 grid acceptance.

ILI chief executive Mark Wilson said: “This second tranche builds on the momentum of our Q1 Gate 2-ready portfolio.

“With [clean power 2030] setting a clearer framework for delivery, we’ve ensured this next batch of projects is equally well-positioned to move forward at pace.”

ILI has already sold over 650MW of battery storage projects, and the company is also developing several PSH projects in Scotland.

The firm sold its 500MW Loch na Cathrach project to Norway’s Statkraft in 2023.

US asset manager buys UK solar and battery developer

American investment firm Federated Hermes has acquired a UK-based renewable energy project developer with a pipeline of solar and battery storage projects.

The New York-listed firm’s UK subsidiary will take over Rivington Energy Management, which owns project developer Renewable Connections.

The London-headquartered developer has secured planning consent for more than 1 GW of solar and storage capacity across 25 UK projects since 2021, Federated Hermes said.

Renewable Connections is also involved in the Selms Muir solar and hydrogen project alongside Hygen and European Energy UK.

The 40-person Rivington team will join Federated Hermes’s existing infrastructure business.

International energy storage news

TotalEnergies to invest in six German BESS sites

French oil and gas supermajor TotalEnergies is set to invest €160m (£137m) in six German BESS projects developed by its subsidiary Kyon Energy.

TotalEnergies acquired Kyon in 2024, and the company said most of the BESS sites will utilise next-generation battery technology supplied by Saft, another Total subsidiary.

Total said construction on the six projects, totalling 221 MW of storage capacity, began at the end of 2024 with commissioning planned for early 2026.

Energy Vault secures $28m for hydrogen BESS microgrid

Swiss energy storage developer Energy Vault has secured $28m (£22m) in project financing for a green hydrogen and BESS hybrid microgrid in California.

The Calistoga Resiliency Centre (CRC) project integrates advanced hydrogen fuel cells with lithium-ion batteries.

The system is designed to address power resiliency amid growing wildfire risks in the Napa Valley wine region of California.

Energy Vault said the 293 MWh microgrid can deliver close to 48 hours of continuous energy supply for the Calistoga community if the town is cut off during a fire.

© Image: Energy Vault

The firm is developing the CRC project alongside PG&E, with construction already completed and full commercial operation expected in the second quarter of 2025.

Energy Vault said CRC serves as a model for its future utility-scale hybrid microgrid storage system deployments.

Energy Vault chief executive Robert Piconi said CRC is the first of two energy storage assets the firm expects to bring online this quarter.

“As California faces increasing wildfire risks, the CRC demonstrates how advanced energy storage technology can help communities maintain critical services and safety during necessary power shutoffs,” Piconi said.

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Charging Forward, bringing you the latest in UK and international energy storage news, is kindly sponsored by ABB BESS-as-a-Service.