Thornton Bank Offshore Wind Farm, Belgium

Thornton Bank is the first offshore wind farm to be constructed in Belgium. It is located in the North Sea, about 30km off of the Belgian coast.

The project is being constructed in three phases, with a total installed capacity of 325MW. The total development cost amounts to approximately €1.3bn.

The first phase has been in commercial operation since June 2009. In the first six months of operation, it operated at a technical availability rate of 94%.

This increased to 97% in the next six months from January to June 2010. The second and third phases are expected to come online in 2012 and 2013 respectively.

On completion, the wind farm will produce generate about 1,000GWh of electricity, sufficient to meet the requirements of about 600,000 Belgian households. Compared to a modern gas-fired power plant, the wind farm will offset about 450,000t of carbon dioxide emissions each year.

Electricity generated by the first phase is being sold to Eneco (Belgium), a Dutch company specialised in the production, trading, transmission and supply of gas, electricity and heat, as well as other related services. Eneco will also purchase half of all the power produced by the second phase of the wind farm.

Project finances behind the offshore wind farm

Belgium's first offshore wind farm is also the largest project-financed one in Europe. The project reached financial closing in November 2010.

A total of seven commercial banks, together with the European Investment Bank (EIB), Eksport Kredit Fonden (Danish export credit agency) and Euler Hermes (German credit export agency) are providing long term facilities, totalling €869m.

The seven commercial banks are all from Europe and include Societe Generale, KBC, Rabobank, Commerzbank, Dexia and ASN Bank.

Details of the first Belgian offshore wind farm

Thornton Bank offshore wind farm will ultimately be installed with 54 REpower wind energy turbines. Phase one, with total power production capacity of 30MW, was installed with six REpower 5M type wind turbines, each rated at 5MW.

A total of 48 REpower 6M type wind turbines are envisaged for the second and third phases, with each of them having 24 6.15MW wind turbines. These will have a total installed capacity of 295MW.

The wind farm is located 26km from the shore in water depths ranging from 12m to 27.5m. The first phase, which was a pilot project, is built in an area of one square kilometre. The second phase is being developed in an area of ten square kilometres and the third phase will cover around 12 square kilometres.

The generated electricity will be transmitted ashore to the feed-in station in Sas Slijkens, via two three-phase 150kV submarine cables.

Development and construction of Thornton Bank

The necessary environmental permit and domain concession for the wind farm was obtained in 2003. The required building permits for ashore and far shore cabling works were subsequently received between 2003 and 2006.

The project is being developed in two sub-areas, designated as sub-area A and sub-area B. The project developers opted for split location so as not to interfere with the navy's anti-mine and target practice areas. This also ensures the project site maintains a minimum distance of 0.5km from nearby gas pipelines and telecoms cables.

Located to the west of the Concerto South 1 telecoms cable, sub-area A is intended to be installed with 24 wind turbines. Sub-area B, located to the east of the Interconnector Gas Pipeline, is to be installed with 30 wind turbines.

Construction on phase one of the project commenced in May 2007. All the wind turbines were installed in 2008 and were connected to the power grid in the last quarter of that year. The last wind turbine was started up in May 2009.

Construction on the second phase commenced in 2011. The 24 wind turbines for this phase are expected to be installed by mid 2012. Installation of another 24 wind turbines for the third phase are planned to take place by mid 2013.

All the wind turbines are to be installed on concrete gravity base foundations.

Project developer and contractors involved with the Belgian wind farm

The project is being developed by C-Power, which is owned by a number of shareholders. RWE Innogy, with a 26.73% stake in the project. is the largest shareholder.

Other shareholders include DEME (Belgian dredging and hydraulic engineering group), Societe Regionale d'Investissement de Wallonie (SRIW), Ecotech Finance (the environmental holding company of Walloon Investment Company), SOCOFE (the investment company of the public administrations of the Walloon Region), NUHMA (Investment vehicle for the participation in electricity and utility ventures) and EDF Energies Nouvelles (a 50%-owned subsidiary of the EDF group).

C-Power adopted a multicontract strategy for the delivery of the first phase. The first contract was awarded to the Seawind consortium, comprising Dredging Marine and Electrical Infrastructure Works (MEC).

REpower was contracted to design, supply, transport and install the wind turbines. It will also supply 48 wind turbines for the second and third phases. ABB was contracted for the supply and connection of the marine export and in-field power cables.

ABB was again awarded a $125m contract for the second and third phases. Jacket foundations at the wind farm were installed by OWEC Tower.

Technum and IMDC, from Belgium, and DONG Energy from Denmark were the owner's engineers. COWI was sub-contracted by Dredging International to provide detailed design of the gravity base foundations. Mott MacDonald was the lender's engineer.