Europe’s Biggest Battery Supports More Renewable Energy on the UK Power Grid

Zenobē, a grid-scale battery storage specialist, and Wärtsilä Energy Storage have launched a project designed to store excess power from several offshore wind farms in the North Sea.

Power grid operators are recognizing the importance of energy storage when it comes to integrating renewable energy to electricity transmission and distribution systems. The integration of wind and solar power requires reliable energy storage systems due to those resources’ intermittent and variable natures.

Energy storage systems are crucial for effectively integrating wind power into the grid, because wind energy is inherently variable and unpredictable. Grid operators know that without storage, fluctuations in wind intensity can cause grid instability. By storing excess energy generated during windy periods, energy storage systems can release it when wind speeds decrease, helping ensure a steady and reliable power supply.

The 200-MW/400-MWh energy storage system provided by Wärtsilä Energy Storage to owner and operator Zenobē in Blackhillock, Scotland, entered commercial operation earlier this year. The Blackhillock Battery Energy Storage System at commissioning is the largest battery energy storage site operating in Europe, and is the first project delivered under the Network Options Assessment (NOA) Stability Pathfinder program, “a landmark initiative by the UK’s National Energy System Operator (NESO) designed to ensure long-term grid stability as the country transitions to renewable energy,” said Christopher Wolf, area sales director for Africa and Europe at Wärtsilä Energy Storage. “The program identifies and procures innovative solutions that can replace the critical system services—like inertia and short-circuit current—traditionally provided by fossil fuel-based power plants. By doing so, it supports the UK’s goal of operating a fully decarbonized electricity grid by 2035.”

1. This diagram shows the location of the Blackhillock site (letter “B” in the diagram), highlighting its connections to wind farms in the North Sea, as well as its place within the regional power transmission network. Courtesy: Zenobē

A second phase of the Blackhillock project (100 MW/200 MWh) will come online next year. Zenobē officials said Blackhillock is “deliberately located” between Inverness and Aberdeen to address grid congestion from the Viking (443 MW), Moray East (950 MW), and Beatrice (588 MW) offshore wind farms in the North Sea (Figure 1).

Zenobē, a grid-scale battery storage specialist, secured£101 million ($135.7 million) in debt financing via a long-term debt facility from a club of five banks to support construction of phase one of the project. The debt structure includes an accordion facility to debt finance the second phase of the project.

Supporting the Grid

Zenobē said the system will assist grid operators in managing challenges related to balancing supply and demand, power stability, and constraints along the grid. The Blackhillock site is the first to provide stability services to the NESO, making grid integration of renewable power more reliable and secure. The stability services include short-circuit level and true synthetic inertia, which are essential for the grid to function efficiently as the UK moves toward phasing out fossil fuel power plants. Officials recently said the system will enhance the reliability of the UK’s growing renewable power system, and help save energy consumers more than£170 million ($228 million) over the next 15 years.

“Blackhillock is the world’s first battery energy storage system to provide both true synthetic inertia and short-circuit current at scale to the UK’s National Energy System Operator. This is a game-changer for the grid,” said Wolf. “Historically, large thermal power stations provided these essential services. As the grid decarbonizes, battery energy storage systems are emerging as a crucial technology to support this transition efficiently. Using advanced grid-forming inverters from SMA, and our advanced controls and optimization software, Blackhillock delivers synthetic inertia at this scale—mimicking the physical inertia that stabilizes frequency—and short-circuit current support, which helps the system respond effectively to faults. Together, these capabilities maintain reliability and unlock greater integration of renewable energy, all while moving the UK closer to its zero-carbon goals.”

“Our batteries at Blackhillock are the first to use advanced power electronics to enable a much higher uptake of renewable power on the grid. This dramatically reduces costs to consumers and increases reliability. Zenobē is the first to deliver this capability at scale and we are helping the UK to become more competitive through increasing the availability of clean, affordable power,” said James Basden, founder and director of Zenobē.

Valuing Wind Power

Zenobē officials said Blackhillock will ensure that much of the region’s abundant wind power generation is not wasted, and it supports the UK government’s mission to have a net-zero power grid by 2030. Zenobē said the project will prevent about 2.6 million tonnes of carbon emissions over the next 15 years as it helps integrate more wind power into the power transmission network.

The Blackhillock site uses Wärtsilä Energy Storage’s Quantum battery energy storage system, along with the GEMS Digital Energy Platform, which allows Zenobē to remotely monitor and operate the equipment. GEMS eases network constraints by importing electricity at times of peak renewable generation. Its data-based intelligence will enable Zenobē to participate in the most valuable UK electricity markets, with predictive analytics and optimized energy dispatching.

“GEMS Digital Energy Platform is the intelligence behind the Blackhillock battery system. While the Quantum hardware stores and dispatches electricity, GEMS acts as the control center for the system as a whole—coordinating how and when that energy is dispatched,” said Wolf. “The Blackhillock system requires especially advanced coordination through GEMS since it is partitioned into multiple Balancing Mechanism Units (BMU), each with its own market service stack. GEMS manages this stack for each BMU while also managing compliance to grid code for the entire site. Within each BMU, GEMS optimizes the allocation of power to minimize state-of-charge (SOC) error and maximize usable energy and efficiency.”

Wolf continued: “GEMS empowers Zenobē to unlock the full economic value of the storage system. It allows multiple market participants—or tenants—to operate independently on a single site, trading energy across different electricity markets, such as frequency response, balancing services, and wholesale trading. This multi-tenant functionality, combined with precision control over real and reactive power, means Zenobē can maximize revenue opportunities while ensuring the plant remains compliant with grid codes. GEMS orchestrates these instructions seamlessly, making it possible to optimize both stability services and commercial returns.”

“As Britain increases its reliance on renewable energy sources such as wind and solar, systems like Blackhillock will ensure that excess power can be stored and then used during times of increased demand,” said David Hebert, vice president of Global Sales and Business Strategy at Wärtsilä Energy Storage. “Blackhillock sets a new standard and plays a pivotal role in balancing the grid and supporting the UK’s path to 100% renewables.”

Scottish and Southern Electricity Networks (SSEN) delivered the grid connection required for the site to harness the renewable energy on its transmission network. EDF Wholesale Market Services will be the route-to-market provider for the site, through its Powershift trading platform. This platform, combined with Zenobē’s battery optimization experts, will build more flexibility into the grid, essential to reducing wind curtailment and accelerating the decarbonization of the network.

Fintan Slye, CEO of NESO, said, “Our 2025 ambition to enable zero carbon operation of Great Britain’s national electricity network is central to NESO’s mission. The delivery by Zenobē of this grid-forming battery is a major accomplishment and brings us a step closer to this goal. Battery storage is critical to the future reliability and affordability of the UK grid and pairing it with this grid-forming technology can unlock even greater resilience for a net-zero network.”

Zenobē is a UK-headquartered electric vehicle fleet and grid-scale battery storage specialist. The company is the leading owner and operator of grid-scale batteries on Britain’s transmission network, and is expanding into Australasia and North America. Zenobē has 735 MW/1,300 MWh of battery storage assets in operation or under construction.

Wärtsilä Energy Storage also is supplying a second project to Zenobē. The 300-MW/600-MWh Kilmarnock South installation also is being delivered under the Stability Pathfinder program. It is expected to be operational by the end of 2025.

—Darrell Proctor is a senior editor for POWER.