Europe is racing to add very large grid batteries to balance rising wind and solar output. As of mid–late 2025, four utility-scale Battery Energy Storage System (BESS) projects stand out by size — each designed in the 0.5–2.8 GWh class and backed by reputable developers and public filings. Below I summarise each project, its capacity, status and why it matters.
1. Green Turtle (Rotem / Dilsen-Stokkem, Limburg — Belgium)
Capacity: 2,800 MWh (2.8 GWh) —700 MW output.
Developer: GIGA Storage Belgium (engineering partner Sweco announced as designer).
Status (mid–late 2025): Permitted and moving toward construction (construction cited to start in 2025 with completion targeted later in the decade).
Expected completion: Public reporting cites a multi-year build timetable with target completion around 2028.
Why it matters: At ~2.8 GWh this is currently the largest single BESS project announced in continental Europe and would provide long-duration grid flexibility at a scale comparable to multiple conventional peaker plants.
Also Read: Encavis AG constructs its first Battery Energy Storage System in Germany
2. Alyth BESS (near Alyth, Perth & Kinross — Scotland, UK)
Capacity: 1,800 MWh (900 MW).
Developer: EcoDev (Alyth) Ltd.
Status (mid–late 2025): Secured development consent from Scottish authorities — the project is a large consented BESS and awaits construction scheduling and commercial steps.
Expected completion: Not yet fixed publicly; construction would follow post-consenting and contracting.
Why it matters: At 1.8 GWh / 900 MW this consented project is one of Europe’s largest single BESS assets and illustrates how the UK / Scottish permitting route is enabling gigawatt-scale storage deployment.
3. Coalburn 1 (South Lanarkshire — Scotland, UK)
Capacity: 1,000 MWh (500 MW).
Developer: Copenhagen Infrastructure Partners (CIP) with partners/investors.
Status (mid–late 2025): Under construction — CIP announced final investment decision and construction start in 2023 and has completed commercial deals and partial equity sales since then. Commissioning was expected in the 2025–2026 window.
Expected completion: Commissioning was broadly targeted for early 2026.
Why it matters: Coalburn 1 was one of the first projects in the 0.5 GWh scale to reach FID and construction in the UK, serving as a commercial precedent for larger portfolios and attracting institutional capital.
4. Coalburn 2 (South Lanarkshire — Scotland, UK)
Capacity: 1,000 MWh (500 MW).
Developer: Copenhagen Infrastructure Partners in partnership with storage specialist Alcemi.
Status (mid–late 2025): Advanced development with FID updates and equity transactions reported; construction plans form part of a multi-site Scottish portfolio.
Expected completion: Public developer statements target mid-to-late decade commissioning for the wider portfolio (individual site schedules vary).
Why it matters: Coalburn 1 and 2 form part of a wider Scottish portfolio attracting major institutional investors. Together, they make Scotland a hub for large-scale BESS.
What this cluster of projects means for Europe
Scale shift: Until a few years ago, most European BESS were tens of MWh. Projects now announced at the 0.5–2.8 GWh scale are a step-change in the role batteries can play — not only short-term frequency response but multi-hour to long-duration energy shifting.
Finance and market signals: Institutional investors (insurers, infrastructure funds) and long-term offtake/optimisation contracts are appearing alongside these projects, signalling a maturing asset class capable of raising large project finance.
Geographic clustering: Scotland has become a hotspot for large BESS (the Coalburn projects and other portfolio assets), while continental projects such as Green Turtle show similar ambitions in Belgium and the Low Countries.
While these projects boast massive planned capacities, the largest active BESS in Europe is now the first 400 MWh phase of ENGIE’s 200 MW / 800 MWh system in Vilvoorde, Belgium, which has officially gone live.
