According to a study carried out by federal offshore wind regulator Creg on behalf of the energy ministry, the recent strike prices awarded in the Netherlands — €72.70/MWh for Borssele 1 and 2 and €54.50/MWh for 3 and 4 — with prices agreed for operating and future projects in Belgium.
Creg modelled publicly available information and applied it to the Belgian projects, taking into account differences such as the density of turbines, tax regimes, support duration and operating costs.
The regulator estimates that the support for Borssele 1 and 2 transposed to Belgium would give a price of €76.27-84.27/MWh.
The Belgian government last year agreed a strike price of €124/MWh for Norther and €129.8/MWh for Rentel, excluding grid connection.
The study also compared Borssele 3 and 4 with Northwester 2, one of three Belgian projects yet to agree a strike price. According to Creg, it should receive €62.14-80.45/MWh, excluding connection.
However, the industry is not convinced by Creg's analysis and has commissioned its own study. "We see a lot of differences (Creg) didn't incorporate," said Antoon Soete, strategic consultant at advisory firm 3E.
For Soete, the main differences in price between Belgium and the Netherlands can be explained by the size of the concessions and the density of turbines.
The Belgian projects are much smaller - Norther and Rentel are 370MW and 309MW respectively, while Borssele is divided into two 700MW blocks - and developers were encouraged to maximise the number of turbines.
The density in Belgium is two to three times that of Borssele, resulting in far greater wake effects and lower output.
"The wake effects on full-load hours is one of the most important parameters for offshore wind farms," said Soete. "This is reflected in the differences in the levelised cost of energy in the two countries."
Smaller projects mean fewer economies of scale and less freedom to choose the best, and least costly, seabed conditions for each turbine.
And the Belgian projects were also awarded to smaller players that have to rely on project finance, which is more expensive than funding off the balance sheet, said Joel Meggelaars, head of advocacy at WindEurope.
It is worth noting that the Belgian projects were awarded several years ago under a very different policy framework.
Projects were selected on the basis of technical quality and financial strength. The tariff was only agreed later, once developers had already made substantial investments.
Developers have been hit by long lead times. "Rentel was awarded in 2009, but then had to wait until 2016 to learn what the regulatory system would look like," explained Annemie Vermeylen, secretary general of the Belgian Offshore Platform (BOP), an association of investors in offshore wind.
Lack of grid capacity caused further delays. "If everything had gone as planned, the projects would have been built before now," she adds.
Since the release of the study, Philippe De Backer, secretary of state for the North Sea, has said that he is looking to withdraw the concessions for the Northwester 2, Mermaid and Seastar projects (totalling 742MW) and re-offer them in a new tender to allow the market to dictate the price.