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Ideol: foundations for floating wind turbines

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Ideol: foundations for floating wind turbines

Energies Marines

Ideol’s first inroads into the French and Japanese markets are a result of its innovative foundation concept for floating wind turbines. Made from steel or concrete and designed to support 2–8 MW turbines, Damping Pool® foundations are square structures with a typical side length of 35 to 55m. “We developed and patented a ‘square form’ foundation limiting the motion of a barge carrying an offshore wind turbine. This technology promises to radically improve the economics of offshore wind farms given that it will reduce unit costs and is scalable to the largest projects. Other technologies offer certain benefits, but are either too expensive or too bulky. Ideol’s Damping Pool® ‘floaters’ are the most compact and shallower, which means that they can be readily built in small ports without special infrastructure,” says Paul de la Guérivière, CEO of Ideol.

Water depth is not a factor

With a draught of just 7 to 8 metres, the cost of a Damping Pool® foundation is comparable to that of a conventional bottom-fixed foundation at a depth of 35m. The chief advantage of floating turbines is that they can be installed farther off shore, where wind conditions are more favourable but where the sea is too deep for fixed foundations. “With floating foundations, water depth is no longer an issue. Our expertise is the result of years of experience in the offshore service industry, including many deep-water projects. We offer a range of mooring options, depending on local conditions, including chains, synthetic-fibre cables, semi-taut catenary lines, conventional drag-embedded anchors, driven pile-type anchors, or a combination of these methods. In each case, we aim for the most appropriate and cost-effective solution.”

Steel or concrete?

Another advantage of Damping Pool® foundations is that they can be made of steel or concrete. “It all depends on local market conditions, the overriding aim being to achieve 100% local content. In Europe, concrete is more cost-effective; in countries with strong steel and shipbuilding industries, steel may be more economical.” The concrete itself can be of different grades. “Whether it is conventional or ‘light’ depends on local conditions. Swell, depth of the water and the choice of wind turbine are all determining factors. Once these factors are known, we optimise the design while taking into account not only costs, but also fabrication, installation and operating constraints.”

 

 

A suite of skills

Ideol is based in La Ciotat in the south of France. From modest beginnings in 2010, the company now employs 50 full-time staff, mostly engineers. Paul de la Guérivière believes that one of Ideol's strength lies in the team’s integrated skillset spanning the entire project life cycle. “We don't subcontract anything; not even mooring computations. This is what makes our know-how dependable and enables us to adapt to local conditions. We supply the expertise to meet every project constraint.”

Ideol is currently working on three contracts.

Demonstrator operational in 2017

The first contract is for a Damping Pool® demonstrator now approaching completion at Saint-Nazaire. This concrete foundation is being built by Bouygues as part of the Floatgen project. It measures 36m x 36m, is 10m high and will support a 2‑MW Gamesa turbine. The seven European partners in the Floatgen consortium achieved their initial objective of setting up a full-scale feasibility test to validate the technology and qualify the moorings and anchoring. The demonstrator is scheduled to be commissioned at sea in mid-2017 at the SEM‑REV test site off the Atlantic coast operated by the École Centrale de Nantes engineering school.

First pilot wind farm in the Mediterranean

In July 2016, Ideol won a French government tender to develop and build the first offshore wind farm in French waters. The pilot project calls for four concrete Damping Pool® foundations, each supporting a 6‑MW Senvion turbine. The turbines are already on site at the Gruissan offshore wind farm developed by the Quadran renewable energy group 15km off the coastal town of the same name.

 

(© : IDEOL)

(© : IDEOL)

Success in Japan

After submitting bids for other sites in France, Ideol recently landed its first international contract with the Japanese group Hitachi Zosen (Hitz). Announced in 2016, with construction set to begin in Q3 2017, this project calls for two demonstration wind turbine floaters using the Damping Pool® design, one in steel and one in concrete. Each foundation or floater will be anchored in up to 100m of water using mooring lines made of different materials with each supporting a different type of 7.5‑MW wind turbine.

This project is all the more important given that Japan may well prove the biggest wind energy market in the medium term. The Japanese government aims to install floating wind turbines totalling 25 GW by 2030.

Poised for commercial production

With an upward trend in the number of projects in Europe too, Ideol plans to capitalise on its innovations and current projects to establish itself as a global leader. “We are not quite ready for commercial production, but we are very close. Once the pilot wind farms have demonstrated the technology’s feasibility and performance, we will begin commercial production. We expect this to take another three or four years.” Wind farms with dozens of floating turbines are envisaged.

Written by Vincent Groizeleau, translated by Steve Dyson

 

(© : IDEOL)

(© : IDEOL)

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