Transformers manufactured by a Leeds firm are playing a critical role in Europe’s largest battery energy storage system (BESS) by megawatt hours, which has just come online in East Yorkshire.

Harmony Energy’s 98MW/196MWh Pillswood facility, near Cottingham, utilises 78 Tesla Megapacks connected to the grid using power and distribution transformers. These transformers ensure the voltage of the imported and exported energy matches the voltage level of the grid connection.

Wilson Power Solutions supplied the site with Forty Tier 2 compliant 2.8MVA 33kV/480V Wilson T2 Ecotrans Distribution Transformers®. And to blend in with the white Tesla Megapacks, Wilson Power Solutions supplied its transformers in the trademark Tesla colour.

Located in East Yorkshire, Pillswood has a strategic significance in supporting the utilisation of non-dispatchable renewable energy projects. The site is adjacent to National Grid’s Creyke Beck substation, the same connection point proposed for phases “A” and “B” of the world’s largest offshore wind farm, Dogger Bank, which is set to go live on the first phase in Summer 2023.

The National Grid Energy System Operator has asked wind farms to switch off in the past in the occurrence of consumption/generation imbalance occasions. Battery Energy Storage Systems like Pillswood prove necessary to allow the NG to maximise the utilisation of the energy generated by wind farms.

Tesla managed the construction of Pillswood which is also operated by Tesla Autobidder, a real-time trading and control platform providing asset management and portfolio optimisation based on value. This allows Pillswood to provide balancing services to the GB electricity grid while maximising revenues.

Funded by Harmony Energy Income Trust and delivered by Harmony Energy Limited, the two-hour duration BESS site has the capacity to store up to 196 MWh (megawatt hours) of electricity in a single cycle. This is enough to power around 300,000 UK homes for two hours.

Further information about Wilson Power Solutions can be found on their website,


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