Battery Energy Storage Systems
Across Europe, we develop, build, operate, and own high-quality Battery Energy Storage Systems (BESS), unlocking the full potential of renewable energy. Our BESS help balance electricity supply and demand, enabling a reliable, low-carbon energy future.
Why Battery Energy Storage?
Following a turbulent period of global energy uncertainty and rising costs, the UK is accelerating its shift towards a more secure, homegrown energy system. Battery energy storage systems (BESS) are critical to that transition because they enable renewable energy to deliver consistent, reliable electricity when it’s needed.
As renewable energy becomes a larger part of our electricity mix, managing its naturally variable output is essential. BESS captures surplus power and stores it for when demand is high. When the wind drops or the sun isn’t shining, stored energy is released back into the grid to keep power flowing.
But the benefits go even further. The net zero sector is driving investment and creating skilled jobs across construction, engineering and project lifecycles. This helps power both the economy and the clean energy transition.
Supporting homegrown clean energy
Enhancing biodiversity and wildlife
Strengthening national energy security
Reducing CO2 emissions
Making energy bills more affordable
Reducing wind curtailment
Allocating funds and sponsorship
Preventing blackouts
Jobs, Growth and Community
BESS are not just about energy security and climate action. They also deliver significant economic benefits, including local business rates, GVA (Gross Value Added), community funds, and job creation. BiGGAR Economics conducted an independent analysis of 10 projects developed and energised by Harmony Energy and found that, over their lifecycle, these projects are estimated to generate £349 million in GVA, support 3,000 job-years, and contribute almost £5 million in fiscal revenue each year during operation.
How do they work?
Battery energy storage systems help renewable energy flourish. They store electricity when generation exceeds demand, like on sunny or windy days, and release it when it’s needed, keeping the grid stable. This ensures reliable energy supply, and reduce reliance on fossil fuels. Watch our animation to see BESS in action and understand their vital role in a cleaner, greener energy future.
Did you know?
The multi-award winning Bumpers BESS, developed and energised by Harmony Energy, was showcased by the BBC as one of the top five reasons to be optimistic about climate, commenting, “According to experts, batteries are the key link in the chain that will makes net zero achievable for electricity production.”
FAQs
1. What is a Battery Energy Storage System (BESS)?
2. How does a BESS help the environment?
On a local level, each scheme is designed to the highest standards, with appropriate landscaping to ensure the site is appropriately screened.
3. What is the impact on Biodiversity and Wildlife?
At Harmony Energy, we take the impact on wildlife and the environment very seriously.
As part of a planning submission, full ecological surveys are carried out ahead of any development, and ecologists are on site to monitor the works where required throughout development.
The Environment Act 2021 requires all developers to plan for biodiversity improvements on new development sites. The current standard is that a 10% biodiversity net gain should be provided – in effect, this means leaving the natural environment in a 10% better state than beforehand. Despite this, we endeavour to provide a greater percentage than the statutory requirement to maximise the benefits our sites can deliver.
Find out more about Harmony Energy’s sustainability approach here.
4. How do BESS support energy security?
5. Are BESS safe?
The Renewable Energy Planning Database (REPD), which tracks energy projects through the planning system, has recorded only two BESS fires in the UK (which utilised different technology) requiring Fire and Rescue Service attendance: one at Carnegie Road, Liverpool in September 2020, and another at East Tilbury in February 2025 (cause still under investigation). Given an estimated 6 million hours of operation, this equates to approximately 0.00000033 failures per hour, significantly lower than many other infrastructures located within communities.
Importantly, there have been no fatalities, third-party injuries, or environmental damage resulting from BESS incidents in the UK.
6. Do you consult with fire services?
7. How does BESS support local communities?
Harmony Energy seek to provide a range of benefits designed to ensure the project brings lasting value to the local area, not just through clean energy, but through direct support for the community including local jobs and sponsorship opportunities.
We will provide an annual Community Benefit Fund to financially support causes that are important to local people and communities. We are also exploring annual payments to residents living closest to our proposed sites. These would be designed to help with rising energy costs.
We also host workshops and tours around our operational sites to learn about renewable energy and sustainable practices, and sponsor local events and organisations where appropriate.
Find out how Harmony Energy is supporting communities here.
8. What does a BESS site look like?
9. What criteria do you apply to site selection for battery energy storage systems?
After identifying a grid connection point, we conduct detailed analysis of the surrounding available land to find sites with the lowest possible impact on nearby residents, built heritage, ecology, cultural sites, and landscape.
10. Would there be increased traffic in the neighbourhood?
11. Are there any increased flood risks?
12. Can a BESS cause blackouts or power interruptions?
13. What happens to batteries at the end of their life?
14. I've heard BESS are dangerous. Is that true?
At Harmony Energy, safety is our top priority. BESS are subject to strict regulations and rigorous safety standards. Real-world data shows that BESS incidents are extremely rare and have not caused harm to people or the environment in the UK. We believe in sharing clear, evidence-based information and welcome open conversations to address any concerns honestly and transparently.
15. Are BESS noisy?
We believe transparency is vital. If our FAQs haven’t covered what you’re looking for, or you’d like to learn more about any aspect of our battery projects, we’d love to hear from you.
A selection of Harmony Energy's energised sites
Pillswood (98 MW / 196 MWh)
A flagship project for Great Britain, the multi-award-winning Pillswood BESS was Europe’s largest battery energy storage system by MWh at the time of its launch in November 2022. Located in Cottingham, East Yorkshire, it remains one of Great Britain’s top-performing assets. View the project timelapse here.
Rusholme (35 MW / 70 MWh)
Energised in August 2024, the Rusholme BESS in Selby, like many of Harmony Energy’s other projects, utilises Tesla Megapacks and is operated through Tesla’s Autobidder algorithmic trading platform. Built on the backdrop of nearby wind turbines, the site demonstrates cutting-edge energy storage technology in action.
Energised in March 2024, the Jamesfield BESS, near Abernethy, Scotland, marks Harmony Energy’s second operational battery storage project in the country and the second energised joint venture with TagEnergy, a global clean energy enterprise.
Located at the Port of Nantes–Saint‑Nazaire Harbour, the Cheviré project was France’s first large‑scale, two‑hour duration BESS. Energised in August 2025, the site has the ability to power approximately 170,000 homes for two hours, exceeding the population of Nantes.
Little Raith (49.5 MW / 99 MWh)
Energised in October 2023, the Little Raith BESS was one of Scotland’s largest at the time of launch and marked Harmony Energy’s first operational BESS in the country. Launching at a similar time to Bumpers, the combined sites can power approximately 450,000 homes for two hours.
Chapel Farm (49.5 MW / 99 MWh)
Energised in May 2023, the Chapel Farm BESS was the first Harmony Energy joint venture with TagEnergy to go live. The site’s official launch in October 2023 brought together teams, partners and key stakeholders to celebrate this milestone in the company’s battery storage portfolio.
Bumpers (99 MW / 198 MWh)
Energised in October 2023, the Bumpers project became the joint largest BESS in Europe by MWh. Multi-award winning and widely recognised in leading international media, including the BBC and Bloomberg, Bumpers has cemented its reputation as a flagship asset in Great Britain’s energy system, demonstrating world-class innovation and supporting the reliable delivery of low-carbon electricity.
Alongside Hawthorn Pit, the Wormald Green BESS was the final site to be energised from the Harmony Energy Income Trust portfolio. Both sites were the first Harmony projects to utilise Envision Energy batteries, marking Envision’s debut operational storage assets in Great Britain and highlighting Harmony’s diversification of battery technology.
Clay Tye (99 MW / 198 MWh)
Developed as a joint venture with FRV, the Clay Tye BESS was one of Europe’s largest at the time of launch. Located in Essex, the site has sufficient capacity to power more than 300,000 UK homes for two hours.