Varco Energy and Fluence Energy UK Ltd. have announced that Phase 1 of the Sizing John Battery Energy Storage System has successfully entered full commercial operations and is simultaneously launching Phase 2 of the project. The 57 MW / 137.5 MWh Phase 1 project is located within the Mersey Ring east of Liverpool, a region known for its acute grid constraints.

Varco has selected Fluence to expand the site by an additional 85.5 MW / 201 MWh in Phase 2, bringing the combined project to 142.5 MW / 348.5 MWh. Upon energization of Phase 2, the Sizing John project will rank among the largest battery energy storage systems in the UK.

Two-Phase Development Strategy

The Sizing John project has been designed as a two-phase development to maximize both immediate and long-term impact. Phase 1 of the BESS has a duration of 2.4 hours, one of the longest for any operational battery project in the UK. This longer duration is intended to help lower overall energy costs by addressing growing congestion in the region and reducing price volatility created by rising renewable generation.

Phase 1 is now fully operational and powered by Fluence's Gridstack solution, providing critical storage capacity to help balance local supply and demand and support renewable integration. Phase 2 has commenced construction with an expected commercial operation date in Q4 2026.

Advanced Grid-Forming Technology

Phase 2 will incorporate the Fluence-supplied next-generation Gridstack Pro 5000 with advanced grid-forming capabilities. This technology will provide critical support to the UK's grid by actively regulating voltage and frequency, delivering essential regional grid stability. Fluence has delivered and operates grid-forming projects worldwide, demonstrating the technology's role in supporting stable, renewable-based power systems.

The importance of such technology has been underscored by recent events, such as the Iberian blackout, which highlighted the urgent need for assets that can independently support both grid voltage and frequency without relying on traditional synchronous generation.

Company Statements and Strategic Context

Richard Whitmore, Director at Varco Energy, stated that bringing Sizing John Phase 1 to operation and announcing Phase 2 demonstrates Varco's commitment to innovation and grid resilience. He noted that the addition of grid-forming capabilities will set a new standard for regional grid support, especially in the wake of the recent blackout on the Iberian Peninsula. Whitmore emphasized that the company is delivering solutions that address current constraints while laying groundwork for a more flexible, renewable-powered future.

Brian Perusse, Managing Director for UK & Ireland at Fluence, described the successful delivery of Phase 1 and expansion to Phase 2 as reflecting the trusted partnership between Varco and Fluence and their ongoing market commitment. He characterized Sizing John as a key step in bringing longer-duration storage and additional grid-forming capabilities to the UK, technologies that play a vital role in improving system resilience, unlocking greater renewable integration, and reducing costs to consumers.

Broader Portfolio Development

This achievement marks the second Varco project to commence operations, following Native River BESS's full commercial operations in April 2025. Over the next 18 months, Varco expects to energize an additional 250 MW of assets in the UK, with an additional 275 MW in its pipeline, fully committing capital from Adaptogen's first fund.

Varco Energy is a UK battery storage asset owner and operator backed by the Adaptogen Capital Battery Storage Fund. With 250MW of assets operating or under construction by 2026, and a further 275MW in its pipeline, the company is committed to helping integrate renewable generation and balance the grid to make sustainable energy accessible and affordable for all consumers.

Adaptogen Capital is described as a specialist battery storage investment firm backed by some of the UK's earliest investors in the storage industry. The firm was founded to provide expertise to investors and help them navigate the energy transition sustainably and profitably. Capital comes from a broad range of family offices and institutional investors, with significant investment from founding directors.

Fluence Energy, Inc. is a global market leader delivering intelligent energy storage and optimization software for renewables and storage. With gigawatts of projects successfully contracted, deployed, and under management across nearly 50 markets, Fluence is working to transform power systems for a more sustainable future.

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