Ostend (Belgium) (AFP)
From the Belgian coast, you have to sail an hour to see the park Norther and its 44 gigantic wind turbines in the sea, a technology that is rapidly gaining power and will soon equip France, helping to green the world energy.
The largest Belgian offshore wind farm to date is 23 km from the ports of Ostend and Zeebrugge, in an area of intense tanker traffic and giant container ships. Completed this summer after two years, it aligns 44 wind turbines up to 200 meters, enough to supply 400,000 households with electricity.
In the midst of the mills rotating in rhythm, a platform appears, looking very small: the electric substation, responsible for centralizing the current to 220 kilovolts, sent via a huge submarine cable ending under the beach of Zeebrugge to join the electricity network Belgian.
But in this sector, these 44 wind turbines are not alone: there are more than 200 others, as far as the eye can see on the horizon, built little by little since 2009 on this dedicated field. Further offshore, two parks are under construction.
Offshore wind currently supplies only 0.3% of the world's electricity (15% in Denmark, 8% in the United Kingdom, 3 to 5% in Belgium, Germany or the Netherlands). But the potential of this young sector is "breathtaking" because of advances in technology, says the International Energy Agency (IEA).
"In the Netherlands, for example, the production price has dropped by 70% in eight years, thanks primarily to the development of larger turbines," explains Lydia Schot, Eneco's offshore wind development manager. the Dutch energy supplier co-developer of Norther Park.
In Norther, each wind turbine (Danish Vestas) has a capacity of 8.5 megawatts (MW), with blades of 82 meters.
A few years ago, the machines were 2 or 3 MW. Today General Electric produces one of 12 MW with blades of 107 meters, announced on several projects in Britain and the United States. And the industry promises 15-20 MW for 2030.
- "Puzzle" -
Taking advantage of strong and regular winds, offshore wind turbines are much larger than land.
In the new parks like Norther, wind turbines are running at full speed almost 50% of the time, an efficiency similar to that of gas or coal plants, notes the IEA.
"The experience gained limits risks and contingencies," says Lydia Schot.
These big projects (1.2 billion euros for Norther, supported by its shareholders and a dozen banks) are actually rarely simple.
There are the remedies. In Ostend, the protest came not from fishermen or ornithologists, but from very large neighboring ports and from a shipping company, around the division of the territory. Norther had to give up square kilometers and a dozen wind turbines, says Tom De Clerck, their license manager.
On land, the calendar also suffered from a recourse against an infrastructure of electric transport.
The technical constraints are also strong.
As the North Sea has suffered two world wars, the Norther site had to be cleared of unexploded ordnance that was still there.
To avoid erosion due to currents, the sea floor was reinforced with stones, while on the path of the cable, the underwater dunes were leveled. At each wind turbine, it was necessary, depending on the layout, to adapt the diameter of the foundation pile, planted 50 meters deep in the clay soil, under 15 to 30 m of water.
"Another problem is that there were already a lot of cables in this area, we ended up with a quirky area (to be converted), but that did not stop us, we made the puzzle!" From Clerck.
Today, Eneco, which was a candidate for the Dunkirk park project (awarded in June to a consortium comprising French EDF), would be well, with other operators, to set foot in France. For a long time slowed down in this country by the recourse and regulatory complications, the offshore wind gets its head out of the water.
Seven parks are planned, the first planned in 2022 against Saint-Nazaire (Loire-Atlantique), and other calls for tenders are expected.
Beyond northern Europe, a pioneer, the IEA anticipates a massive expansion of this energy everywhere, especially in China, provided that the States accompany it.
© 2019 AFP