Stockholm-headquartered engineering consultant Sweco has won a nine-year contract worth at least €48m to advise the Danish Energy Agency on its planned €28bn “energy island” in the North Sea, intended to facilitate a massive expansion in offshore wind power.

Billed as the biggest construction project in Danish history, and approved by the Danish government in February last year, the plan is to build a massive wind farm 80km offshore in the North Sea that will power 3 million households in the first phase from 2033.

The public-private partnership, 50.1% owned by the Danish state, also involves building a 12ha artificial island with a harbour and storage facilities to distribute electricity from 200 turbines.

Sweco’s agreement, which has a price limit of €79.5m (SEK 830 million), sees the company proposing concepts, preparing tender documents, evaluating tenders, and inspecting construction work.

It follows a decision by the agency last month to push back the tendering procedure one year to mid-2023 to give the agency more time to develop the concept and business model and to prepare tender documents in dialogue with interested companies and consortia.

Sweco’s role has expanded from the four-year advisory contract it won on the scheme in July last year, worth €6.7m.

“The energy transition is one of today’s greatest and most important challenges that is creating and will continue to create increased investment needs in many of Sweco’s core segments,” said Sweco chief executive Åsa Bergman. “It is gratifying for us to be part of this journey and contribute to this transition as a prioritised partner for the Danish Energy Agency.”

Sweco said the work involves 11 different professions and around 200 Sweco staff from six countries.

The Danish Energy Agency decided to postpone tendering after two market consultations in 2021.

“We expect that the time we spend on finding good solutions now at the start of the project will enable more intelligent and faster solutions in the long term,” said Mogens Hagelskær, the agency’s deputy director general.

“Developing clever concepts takes time, but there’ll be rewards in the long run,” he added.