BW ESS brings 350 MW Hams Hall battery storage in West Midlands into commercial operation

BW ESS has confirmed that the first phase of its Hams Hall battery energy storage system (BESS) in the West Midlands has entered commercial operation, delivering 350 MW / 1,243 MWh of storage capacity.

According to a company statement dated 2 November 2026, the milestone was achieved in late October 2026 and establishes Hams Hall as the largest battery energy storage system by storage capacity in Europe.

From energisation to commercial operation in 20 days

A notable feature of the delivery timeline is the speed with which the project moved from connection to revenue-generating operation. Commercial operation began just 20 days after energisation, with BW ESS stating that the system was built and commissioned on budget and ahead of schedule. For a project of this scale and complexity, the company characterised the outcome as remarkable and credited the dedication of its team and the collaboration of its partners.

Erik Strømsø, CEO and Co-Founder of BW ESS, called the start of commercial operations "a landmark moment for BW ESS and a significant addition to Europe's energy infrastructure". He added that delivering the project on budget and ahead of schedule was "a remarkable achievement for a system of this scale and complexity and a testament to the dedication and expertise of our team, and the commitment and collaboration of our partners."

Grid connection and system role

Hams Hall sits adjacent to National Grid's Hams Hall substation in the West Midlands, a location that positions the asset to serve the UK's electricity system directly. The project is designed to balance variable electricity demand against intermittent renewable generation, supporting greater integration of renewable energy on the grid. BW ESS also frames the asset as strengthening grid resilience and energy security in the UK.

Partners behind delivery

Bringing the project from commissioning and testing through to operational readiness involved close work with a group of partners including Sungrow, Energy-IO, National Grid and NESO.

BW ESS said that achieving the milestone safely and efficiently reflects the engineering expertise, rigorous preparation and close coordination behind Hams Hall, as well as the technical capability and commitment of everyone involved.

Phase two will lift capacity to 400 MW

The currently operational phase does not represent the full extent of the site. Following completion of a second phase, Hams Hall's capacity will rise to 400 MW / 1,424 MWh. Once the project reaches full capacity, BW ESS says it will be capable of supporting the electricity needs of around 1.3 million homes for up to 3.5 hours — a figure the company notes is approximately equivalent to the number of households across Greater Manchester.

Revenue and financing arrangements

The project's long-term revenues are underpinned by a 10-year floor and optimisation agreement with EDF, providing contracted income alongside merchant optimization. On the financing side, BW ESS recently secured debt from lenders OCBC, Rabobank and Societe Generale, completing the commercial framework for the asset as it enters operation.

A growing UK and European storage portfolio

Hams Hall is one component of BW ESS' 2.6 GWh Ardenham portfolio, which is co-owned with energy and decarbonisation investor AIP Management. Its entry into commercial operations expands the company's operating presence in the UK, where it already runs the 331 MWh Bramley BESS in Hampshire. Beyond its operating assets, BW ESS has 857 MWh under construction at Berkswell, also in the UK, and holds a broader UK development pipeline spanning multiple gigawatt hours.

Company profile and international footprint

BW ESS is a global energy storage owner-operator with activities in the UK, Australia, Italy, Germany, Spain, Sweden and France. The company reports more than 1.8 GWh of operating battery energy storage systems, approximately 10 GWh under or pre-construction, and a development pipeline of several gigawatts. A part of BW Group, the company draws on decades of global infrastructure experience, takes a long-term view of projects and partnerships, and focuses on unlocking value throughout the energy storage asset lifecycle.

With the first phase of Hams Hall now online and the second phase to come, BW ESS' operating fleet and construction pipeline position it among the significant storage operators in the UK market, where the largest operational asset in Europe now carries its name.