Strike hits plant serving Orsted's largest offshore wind project

Staff at monopile plant SeAH Wind walk out today but developer insists Hornsea 3 stays on track

King Charles III meets staff during a visit to at SeAH Wind's factory. Today the plant will be hit by a walkout over pay.
King Charles III meets staff during a visit to at SeAH Wind's factory. Today the plant will be hit by a walkout over pay.Photo: Getty Images

Workers are going on strike at a key factory supplying Orsted’s largest project globally, Hornsea 3, as the developer insisted it will keep the project on track.

More than 150 staff at SeAH Wind in Teesside, northeast England, will walk out today and every subsequent Wednesday for six weeks, said the GMB trade union after negotiations over pay and allowances broke down.

South Korean-owned SeAH is supplying monopile foundations to Hornsea 3, which at 2.9GW is the Danish developer’s biggest wind project and one of the largest globally. It is due for completion in the North Sea by the end of 2027.

The plant will also be hit by an overtime ban, said the union, which is demanding an increase to what it called a “pitiful 3.1% pay offer that's both below inflation and industry standards”.

Strike action would “bring the factory to a standstill” GMB organiser Andrew Blunt has previously claimed.

An Orsted spokesperson said in a statement sent to Recharge: “Negotiations between SeAH and its workforce remain a matter for them. Hornsea 3 remains on schedule and action at the SeAH factory will not impact the Hornsea 3 delivery timeline.”

The vote for strike action is a blow to SeAH Wind weeks after it hailed the start of monopile production for Hornsea 3 by cutting the first steel plate.

The £900m ($1.2bn) SeAH plant, billed as the world's largest making monopiles, was officially opened by Britain's King and Queen in February and was hailed as a symbol of industrial benefits flowing from the UK’s huge offshore wind deployment, which is second only to China’s globally.

The plant’s anchor deal is as one of two XXXL monopile foundation suppliers to Hornsea 3. SeAH Wind is due to deliver monopiles of between 1,300-2,400 tonnes for the project, which is itself crucial to meeting the UK's 2030 offshore wind ambitions.

The £8.5bn ($11.4bn) Hornsea 3 project is also key to stabilising Orsted's finances after a year of turmoil mostly caused by the impact to its US projects by Donald Trump's war on wind.

The Danish group is reportedly in talks to divest a half-share of the project, with one ratings agency warning it could downgrade Orsted if a partial sale fails to materialise by the end of the year.

'Unaffordable and unrealistic'

SeAH Wind said in a statement sent to Recharge: "SeAH Wind is disappointed that the GMB Union and its members have chosen to participate in strike action today."

The South Korean-owned company claimed "an independent report confirmed that SeAH Wind remains competitive within the regional market [for employee pay]" and said some workers had been offered an increase of up to 15.2%.

It added: "The GMB’s current demands are unaffordable and unrealistic. SeAH Wind is at a critical early stage of its journey. We are still in construction, commissioning, and ramping up operations and have yet to deliver our first monopile."

Orsted has been contacted for comment over today's walkout.

Note: update adds comment from SeAH Wind and Orsted
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Published 15 October 2025, 07:50Updated 17 October 2025, 09:28
OrstedOffshoreUKEurope