Extensive salt caverns in Dorset to store hydrogen beneath the former Royal Navy base

Huge salt caverns designed for hydrogen storage will be excavated beneath Britain’s largest former naval base, Portland Harbor in Dorset, as part of a strategic plan to boost the country’s energy security.

The project involves the construction of 19 caves, each the size of St. Paul’s Cathedral, which will store enough hydrogen to fuel a power station for several days. This hydrogen reserve will be crucial for emergency use and provide energy when renewable sources such as wind and solar energy are insufficient.

Claire Coutinho, the energy minister, has approved the plan and updated the company’s policy on hydrogen storage to secure taxpayer subsidies for the project. UK Oil and Gas (UKOG), the company leading the initiative, aims to apply for planning permission within months.

UKOG CEO Stephen Sanderson plans to apply under the government’s Nationally Important Infrastructure Scheme, which could see the project bypass potential local opposition. “Portland Port is ideally located for the construction of large salt caverns as it sits above a 450 meter thick, high-quality rock salt,” Sanderson said.

Sanderson met with key figures from the Department for Energy Security and Net Zero, including Foreign Secretary Claire Coutinho, Lord Callanan, Minister for Energy Efficiency and Green Finance, and Graham Stuart, Minister for Energy Security and Net Zero.

Located in Weymouth Bay on the south coast of England, Portland Harbor has a rich history as a naval base dating back to the 16th century under Henry VIII. It became one of the Royal Navy’s largest bases until its closure in 1995 and now serves as a major port and training center for the British Olympic sailing teams.

The port’s new role in hydrogen storage relies on a substantial layer of halite, or rock salt, found three kilometers below the surface and which has been buried for at least 200 million years. The stability and solubility of this rock make it ideal for creating storage caverns.

UKOG commercial director Matt Cartwright explained that the caves would be formed by drilling wells into the salt and injecting fresh water to dissolve the rock. The project will be managed by UK Energy Storage, a wholly owned subsidiary of UKOG.

Each cave will be 85 meters in diameter and 90 meters high, with a capacity of 320,000 cubic meters – twice as much as St. Paul’s Cathedral.

UKOG is transitioning from its controversial involvement in onshore oil and gas developments in southern England to a future focused on renewable energy. Despite the ongoing legal battle over oil and gas fields in the Weald and Purbeck areas, the company has won the right to drill at the Loxley gas field near Horsham, Surrey, with production expected to start next year.

A spokesperson for UKOG highlighted the company’s strategic shift, saying: “We are moving away from oil and gas and see a much bigger future in renewable energy.”

This ambitious hydrogen storage project marks an important step towards ensuring Britain’s energy resilience, especially as the country transitions to more sustainable energy sources.