Doubling Dutch wind capacity

The Gemini wind park in the Dutch sector of the North Sea has broken financing and renewables project size records. Elaine Maslin takes a look.

An artists’ illustration of the Gemini wind park offshore Netherlands. Photos from Gemini.

In 2014, global investment in renewable energy reached record levels, helped in no small measure by the record-breaking US$3.8 billion financing of the Gemini wind park offshore the Netherlands.

The 600MW project is the largest ever renewable energy project, excluding hydro power, according to a report by Frankfurt School FS-UNEP Collaborating Centre and Bloomberg New Energy Finance, and it will double the Netherlands’ offshore wind capacity.

Construction on the 150 x 4MW, 7m-diameter turbines, plus two transformer stations, in 28-36m water depth, 85km off the coast of Groningen, started late in 2014, with Dutch contractors playing a significant role. Once complete, the park will produce roughly 2.6TWh of renewable electricity.

Gemini’s CEO Matthias Haag says Dutch contractors are playing an important role in the project, led by main engineering, procurement and construction contractor Van Oord, with Siemens providing operations and maintenance for 15 years.

“It is essential to have this supply chain,” he says. “It wouldn’t be impossible without it, but it is certainly a benefit to have these local contractors. Minimal local content is not a given in the Netherlands, but you do see the benefits of it. And, while there have been offshore wind farms before, Gemini is putting it on a different scale. I was involved in the first offshore wind farm in the Netherlands 10 years ago, but there have not been too many built since then. But, the contractors have been working in other countries and bringing back that experience. This project will strengthen that experience further.”

Subsea: wind turbines are mounted on piles, with a jacket-mounted transformer.

For Haag, who has worked for Shell and wave energy firm Aquamarine Power, the Dutch bring marine construction skills, particularly when it comes to tidal flats, which are submerged for part of the day and dry for others, as well as general construction of facilities in water.

A Dutch attitude towards solving engineering problems – allowing contractors to work together to solve issues – also brings benefits. As an example, Haag says Gemini gave contractors BAM and Gebr. van Leeuwen a contract to install two, 500mm-diameter HDPE electrical cable tubes underneath existing cables laid under the sea in the Wadden Sea, for the Gemini export cables. Their solution was to use directional drilling between two jackups, which meant both the entry and exit points, 800m apart, were under water, out of sight. “Drilling from one jack up barge to another jackup barge is not something that has been done very often in the world,” says Haag. “The joint venture came up with the solution and while there were some issues at first, the methodology was changed and it was successful completed in the first quarter.”

For Van Oord, it is a significant project. As well as holding a 10% stake in Gemini, Van Oord is the main engineering, procurement and construction (EPC) contractor, under a EUR 1.3 billion contract which helped tip Van Oord’s turnover over EUR 2 billion for the first time. The project helped underpin investment in both acquisitions – including Ballast Nedam Offshore earlier this year – and two new vessels; the Aeolus offshore installation vessel, delivered in 2014, and the cable layer Nexus, launched at Dutch group Damen Shipyards’ facility in Galati, Romania, last year and now working on Gemini.

Other Dutch contractors involved include SIF, which is supplying the monopiles, Smulders Projects, which is producing the transition pieces, and VBMS, a joint venture between VolkerWessels and Boskalis, which is assisting Van Oord with the export cable installation.

Oceanteam Shipping subsidiary RentOcean is supplying Van Oord with a 3000-tonne demountable onshore turntable system and accompanying equipment for long term cable storage, and the FICG (Fabricom, Iemants and CG) consortium is manufacturing the onshore and offshore transformer stations.

By late July, the project was on track, with most of the manufacturing completed or nearly complete, including transition pieces and turbines. The export cables were already nearly all installed and monopile installation started 1 July, once environmental restrictions were lifted. From 1-23 July, some 25 piles had been installed, and it is hoped all 150 will be installed by year’s end.

Gemini is 60% owned by Canadian renewable company Northland Power, 10% by Van Oord holding, 20% by Siemens and 10% by renewable energy and waste processing company HVC.