The Shetland Islands council has approved a £1.5 billion plan to construct Scotland’s first subsea road tunnels, aiming to address depopulation and enhance economic growth across the archipelago. Drawing inspiration from the Faroe Islands’ network of subsea links, the initiative includes four tunnels that would ultimately replace existing ferry services, offering more reliable and frequent transport connections between the islands. The initial tunnel, connecting Mainland Shetland to the island of Yell, is projected to be completed by 2034.

Home to approximately 23,000 residents spread over 16 inhabited islands, Shetland has a significant economic role in sectors such as oil and gas, renewable wind energy, fishing, and aquaculture. The island of Unst, accessible via a two-ferry journey through Yell, hosts the SaxaVord spaceport, which plans to conduct the first European satellite launch this summer. Additionally, two wind farms are proposed near Yell.

Maggie Sandison, chief executive of the Shetland Islands Council, emphasized the infrastructure’s importance in unlocking further economic development. “Our growth sectors are increasingly on islands off islands, off islands,” she said, highlighting how current transport limitations constrain opportunities. She advocates for a new financial approach combining local contributions, state funding, and road tolls to realize the project’s ambitious goals. Sandison described government investment in fixed road links as “more transformational” than continuing reliance on ferry fleets.

The plan also includes continued support for ferry operations servicing islands unsuitable for tunnel connections, as well as measures to sustain communities during construction. Outer isles have experienced a population decline of nearly 25% over the past 40 years, contrasting with a 5% population increase on Mainland Shetland. The Faroe Islands’ subsea tunnel network, established since 2002, has been credited with boosting inter-island travel, reducing depopulation, and raising household incomes.

Engineering consultants Stantec and Cowi conducted a feasibility study indicating that the council could finance about one-quarter of the £402 million estimated cost for the Mainland-Yell tunnel through borrowing. The remainder is expected to come from Scottish and UK government grants alongside private investment. Sandison also suggested opportunities for wind farm developers to utilize utility corridors within the tunnels for electricity transmission, potentially addressing concerns about the environmental and financial burdens rural communities face from renewable energy infrastructure.

Andy Sloan, a tunnel expert from Cowi, said lessons learned from delayed UK projects like the HS2 rail link could help keep the Shetland tunnels “on time, on budget.” He described the rock excavation method planned for the project as a “relatively simple,” proven technique widely used in Nordic countries. Sloan added that establishing Scotland as a hub for this tunneling approach could represent a significant technical and economic opportunity for the country, noting the industry’s early-stage development.