Three massive steel monopiles, each up to 90 metres long and weighing more than 1,600 tonnes, are travelling from Bilbao to the northeast coast of England. The Trustee, a semi-submersible vessel operated by Boskalis, is carrying the oversized structures to Teesworks for Hornsea 3, which Ørsted describes as “the world’s single-largest offshore wind farm.” Planned at 2.9 GW, the project is expected to generate enough electricity for more than three million UK homes.
Each voyage starts at the port of Bilbao, where Haizea Wind Group manufactures the foundations. Converted in 2008 to carry heavy and oversized cargo, the ship measures nearly 217 metres long and 44.5 metres across. Its 130-metre deck lets it carry three monopiles at a time, something conventional cargo ships cannot do. At sea, custom supports and lashings secure the monopiles against the ship’s movement.
Boskalis says the Trustee will make multiple trips over the coming months, delivering foundations for Hornsea 3 to the UK’s east coast. The first six monopiles reached Teesside in February after travelling roughly 960 nautical miles from Bilbao. The Trustee is a basic link in the logistics chain, but it will not carry all 197 foundations required for the project.
Engineering at Scale
Monopiles anchor offshore wind turbines to the seabed and support the towers above. Haizea Wind Group’s Bilbao facility covers more than 200,000 square metres and employs over 900 people. The company expanded it with an investment exceeding €250 million to meet international demand. Its ability to produce XXL foundations has made Bilbao a critical hub in the global offshore wind supply chain.
Official figures show that the first monopiles for Hornsea 3 measured around 90 metres and weighed an average of 1,670 tonnes. Later deliveries have included larger pieces, over 105 metres long and up to 11 metres in diameter, with a weight of as much as 2,300 tonnes. The 197 foundations will vary, with each batch tailored to specific site requirements.
Hornsea 3: A New Benchmark
Hornsea 3 is taking shape in the North Sea, about 120 kilometres off the Norfolk coast. Developed by Ørsted, the project will have 197 wind turbines with a combined capacity of 2.9 GW, enough to supply more than 3.3 million British homes. The first foundation was installed in May 2026; work on the remaining 196 is scheduled to continue through 2027. The overall project is expected to be finished by the end of that year. Ørsted has put its total cost at £8.5 billion.
The wind farm’s grid connection is a major infrastructure project in its own right. Ofgem launched Tender Round 14 to select an Offshore Transmission Owner (OFTO) to own and operate Hornsea 3’s offshore transmission assets, valued at about £3.5 billion. The regulated process covers the transmission link, not monopile manufacture or delivery. It reflects the separate roles of power generation and grid transmission in connecting the project to Britain’s network.
Alongside the onshore converter station near Norwich, Ørsted has developed the Iceni battery-storage project, a 300 MW system with 600 MWh of storage capacity and 170 Tesla Megapacks. It is designed to share a grid connection with Hornsea 3, storing electricity when generation exceeds demand and releasing it when demand rises. The battery is separate from the wind farm’s foundation-delivery operation, though it forms part of the wider energy infrastructure.
The Trustee’s role is logistical: it delivers monopiles to the UK’s onshore storage site. Other specialist vessels handle offshore installation. Cadeler is responsible for marine transport and installation. The Wind Ally drives the monopiles into the seabed, while the Wind Orca adds secondary steel components. This division of labour reflects the scale and complexity of modern offshore wind construction.
Bilbao’s Growing Industrial Role
The contract has raised Bilbao’s profile in the offshore wind industry, connecting local manufacturing and port logistics with heavy transport for one of Europe’s most ambitious energy projects. Haizea’s Bilbao plant employs over 900 people locally and more than 1,500 across the group, in jobs ranging from advanced welding to technical engineering. The Trustee’s repeated voyages show the region’s industrial capacity and the strategic value of Spanish manufacturing in Europe’s energy transition.
As Hornsea 3 advances, the steady flow of XXL monopiles from Bilbao to the UK supports a major renewable energy project and strengthens Spain’s position in the global offshore wind supply chain. The operation shows how industrial investment and international collaboration are reshaping energy infrastructure across Europe.
