Harmony Energy Tesla Skeeby BESS Wilson T2 distribution transformers

Projects
Skeeby BESS

35MW/70MWh Skeeby BESS

Located near Richmond in North Yorkshire, the 35MW/70MWh Skeeby Battery Energy Storage System (BESS) is a project developed by Harmony Energy, one of Europe's leading developers, owners and operators of utility-scale battery storage. The two-hour-duration system uses Tesla Megapack battery technology and can store electricity generated from renewable sources such as wind and solar. When needed, it will release it back to the grid when demand is high, with enough stored energy to power around 120,000 homes for two hours. The project contributes to a more resilient and flexible UK energy system while supporting the wider transition to lower-carbon electricity.

Sector	Battery Energy Storage System
Developer	Harmony Energy
Project	Skeeby BESS 35MW/70MWh
Location	Skeeby, North Yorkshire, UK
Scope of Work	4.2MVA 33kV/480-480V Wilson T2 Ecotrans® Large Distribution Transformers One 100kVA 33kV/433V Wilson Auxiliary Distribution Transformer

We have supplied ten 4.2MVA 33kV/480-480V Wilson T2 Ecotrans® Large Distribution Transformers and one 100kVA 33kV/433V Wilson Auxiliary Distribution Transformer.

Our Wilson T2 MV Transformers are custom-engineered to Tier 2 loss levels to interface directly with the site's Tesla Megapack battery units via a dual 480-480V LV winding configuration. Each unit has twin 480V secondary windings in a Dyn11yn5 configuration, feeding two Megapack groups from a single transformer. Each transformer is filled with FR3 natural ester fluid, which is a renewable, biodegradable alternative to mineral oil with a significantly higher flash point that enhances on-site fire safety. The transformers are supplied with a 110% steel bund with a hydrocarbon filter, suited to the demands of an outdoor battery site.

70 MWh

storage capacity

Tesla Megapacks

120000

home powered

for two hours

The transformers were delivered in batches between January and April 2026, with each unit offloaded and positioned onto its plinth as part of our delivery scope. Alongside the main battery-interface transformers, we also supplied a 100kVA 33kV/433V Wilson Auxiliary Distribution transformer to serve the site's auxiliary power needs.