Zenobē, which describes itself as the “UK’s leading owner and operator of grid-scale batteries on the GB transmission network”, has announced that Europe’s largest battery site (pictured), located in Blackhillock, Scotland, has begun commercial operation. It is also the first battery in the UK to provide grid forming, and among the first worldwide.
Grid forming batteries provide short circuit level and synthetic inertia via advanced power electronics by mimicking the behaviour of traditional generators. They set their own frequency and voltage, unlike traditional batteries.
The Blackhillock site is launching in two phases. Phase 1, 200 MW, has gone live and will be followed by a further 100 MW in 2026, making a total of 300MW/600MWh.
Deliberately located between Inverness and Aberdeen to address grid congestion arising from the Viking (443 MW), Moray East (950 MW) and Beatrice (588 MW) offshore wind farms, the project is expected to significantly reduce the amount of wasted wind generated electricity and, according Zenobē, can be seen as an important milestone on the way to achieving the UK government’s mission to have a net zero power grid by 2030.
Battery storage plays a critical role in the UK’s net zero transition, as it does elsewhere, with over 22 GW required as a minimum to deliver the UK government’s Clean Power 2030 plan.
In addition to being Europe’s largest battery, the Blackhillock site will provide stability services to the National Energy System Operator (NESO), “to make renewable power more secure and reliable,” says Zenobē.
The battery technology has been provided by Wärtsilä, which is supplying its Quantum energy storage system plus GEMS Digital Energy Platform with SMA grid forming inverters, “enabling a resilient power system with high power quality.”
GEMS eases network constraints by importing electricity at times of peak renewable generation, says Wärtsilä, and ”its data-based intelligence will enable Zenobē to participate in the most valuable UK electricity markets.”
Scottish and Southern Electricity Networks (SSEN) delivered the grid connection for Blackhillock.
EDF Wholesale Market Services is the route to market provider for the site, via its trading platform, Powershift. This platform, combined with Zenobē’s battery optimisation expertise, will build more flexibility into the grid, essential to reducing wind curtailment and accelerating the decarbonisation of the network, says Zenobē.
By integrating this technology, Blackhillock will “enhance the reliability of the UK’s growing renewable power system and help reduce consumer bills nationwide.” The site is expected to save consumers £172 million over the next 15 years. It will also prevent approximately 2.6 million tonnes of CO2 from entering the atmosphere during this period by enabling the accommodation of more wind power on the transmission network.
The new battery system adds over 30% to the capacity of operational battery storage in Scotland. It is estimated that its capacity will be equivalent to powering >3.1 million homes for one hour, Zenobē calculates.
To support the construction of the 200 MW/400 MWh Phase 1 of Blackhillock, Zenobē secured £101 million debt financing via a long-term debt facility from a club of five banks. The debt structure includes an “accordion facility” to debt finance to 100 MW, the second phase of the project.
The estimated consumer savings of £172 million reflect savings of £8 million from avoiding the use of combined cycle power plants to provide inertia and short circuit level plus savings of £164 million arising from the provision of balancing services and constraint management to the grid and helping reduce price volatility. The £164 million of savings from balancing services and constraint management assumes, with degradation over the lifetime considered, that the battery cycles twice a day.
The estimated CO2 savings are benchmarked against the provision of power and/or stability services by a gas peaking plant (540gCO2e/kWh) or combined cycle gas turbine plant (450g CO2e/kWh.
The carbon intensity of imported energy to charge the battery is assumed to be the 2024 national average of 150g CO2e/kWh. This is a conservative assumption, says Zenobē, considering the high penetration of renewable generation and otherwise curtailed power in Scotland when the battery would charge.
The Blackhillock battery system together with the Rothienorman synchronous condenser facility (developed by WP Grid Services and Quinbrook) are the first two grid stability projects to go live of the ten awarded under Phase 2 of the UK National Energy System Operator (NESO) Stability Pathfinder tender programme, aimed at securing future network resilience. The ten projects (total contract value £323 million overall, to secure 11.55 GVA of short circuit level in Scotland and 6.75 GVA.s of Inertia for GB) consisted of five synchronous condensers and five grid forming batteries.
Initially contracted as part of the Pathfinder exercise for ten years, these new projects are expected to provide crucial grid stability services as carbon dioxide emitting power stations are phased out as part of the UK government’s 2030 Clean Power Action Plan. From 2035 the projects will have the opportunity to participate in specific markets for stability services.
Matt Magill, Director of Engineering and Customer Solutions, National Energy System Operator, describes the Blackhillock project as “pivotal,” As the first grid forming battery on the system, it “will unlock new tools for the long-term resilience and security of supply of the electricity system, whilst supporting the delivery of zero-carbon operation.”
Wärtsilä is supplying a second battery project to Zenobē, for Kilmarnock South, also awarded under the NESO Stability Pathfinder programme. Kilmarnock South, a 300 MW / 600 MWh battery storage system, will employ Wärtsilä’s Quantum High Energy storage technology and is expected to be operational by the end of 2025.
Zenobē is an EV fleet and grid-scale battery storage specialist, headquartered in the UK. The company began operations in 2017 and now employs over 300 people.
As well as operating in the UK, it is expanding into Australasia and North America. Zenobē has 735 MW/1300 MWh of battery storage assets in operation or under construction. It has around 25% market share of the UK EV bus sector and supports over 2000 electric vehicles across 120 depots globally. The company says it is the largest owner and operator of EV buses in the UK, Australia and New Zealand.
