Are floating turbines the future of wind energy?

Source: By Jennifer Johnson, Renewable Energy • Posted: Monday, July 18, 2016

Wind turbine technology has come a long way in the quarter of a century since the world’s first offshore wind farm, Denmark’s Vindeby, was installed. The first turbines placed at sea had a capacity of roughly .45MW and stood just 52.5m tall. Manufacturers have since developed larger and more effective turbines, but innovation in wind energy is far from over.

Traditional ‘fixed’ turbines are limited to water depths of around 40 to 50m, mostly relegating offshore wind farms to the shallow waters of the continental shelf. However, deploying turbines further offshore offshore, beyond 100m, could allow them to harvest energy from some of the strongest winds on the planet.

There are currently dozens of pilot projects trialling so-called ‘floating’ turbines — which consist of a wind turbine mounted on a buoyant structure — capable of generating electricity in depths where fixed towers could not be placed. Below, we’ve gathered the details of five promising floating wind projects that could very well revolutionise wind energy all over again.

1. Trident Winds’ Morro Bay Offshore Project

The USA has historically lagged behind Europe when it comes to the uptake of offshore wind. With the country’s very first offshore wind farm scheduled to come online later this year, the prospect of installing floating wind capacity seems even further off. However, Seattle-based project development company Trident Winds LLC is hoping to have turbines bobbing in the Pacific Ocean in just under a decade’s time.

Trident’s Morro Bay Offshore Project, which is still in the planning stages, will consist of roughly 100 floating offshore wind systems (FOWS). Each FOWS is made up of a floating support structure and a wind turbine with a nameplate capacity of 6MW or greater. Initially, Trident is striving for a total nameplate capacity of 765MW with the project, though this has the potential to be expanded at a later date.

The proposed wind farm will be located 33 miles off the coast of Morro Bay, California, where turbines will be able to reap the benefits of average wind speeds of 8.5 miles/second. Trident is aiming to launch the Morro Bay wind farm in 2025.

2. New England Aqua Ventus

Partners: University of Maine and UMaine Advanced Structures and Composites Center, Emera Inc., Cianbro and DCNS.

On the opposite side of the USA, a more modest floating wind pilot scheme just became eligible for almost $40 million in funding from the Department of Energy.

The New England Aqua Ventus project will be comprised of two 6MW turbines placed in the waters off Monhegan Island, Maine. The University of Maine, who are leading the initiative, have stated that the objective of Aqua Ventus is to demonstrate the use of floating wind technologies at full scale.

The project is already backed by a consortium of partners — including French defense company DCNS and construction contractor Cianbro.

Aqua Ventus boasts a floating hull design, which has been tested on a 1:8 scale prototype called VolturnUS.

3. Floatgen

PartnersIdeol, Centrale Nantes, Bouygues Travaux Publics, University of Stuttgart, RSK Group, ZABALA and Fraunhofer IWES

While many of France’s geographical neighbours are world-leaders in offshore wind, the country has yet to install any turbines of its own. This is set to change once construction on Floatgen — a floating turbine with a ring-shaped foundation — is complete in 2017.

Similar to Aqua Ventus, the objective of the 2MW Floatgen turbine is to demonstrate that floating wind turbines are technically and commercially viable. Floatgen will be assembled onshore starting in September and, once complete, will be towed out to sea off the coast of Le Croisic. When the turbine is floating offshore, it will be connected to its anchoring system and an electricity export cable.

The Floatgen project is backed by a consortium of seven European companies and research bodies, including Ideol, who designed the floating foundation; Zabala, a leading Spanish consultant in innovation management and Fraunhofer IWES, who provided comparative analysis of floating solutions.

4. WindFloat Atlantic (WFA) project

Partners: EDP Renewables, (EDPR), Mitsubishi Corporation (through its subsidiary Diamond Generating Europe), Chiyoda Corporation (through its subsidiary Chiyoda Generating Europe), ENGIE and Repsol.

Earlier this month, EDP Inovação Executive Director Luís Manuel confirmed that a project called WindFloat Atlantic (WFA) was entering the advanced stages of development in Portugal.

This comes as Principle Power, an offshore wind technology and services provider, concluded the five-year testing of its 2MW WindFloat prototype, which was installed 5km off the coast of Aguçadoura in northern Portugal.

WFA will  likewise utilise the WindFloat floating foundation as a mount for three or four turbines with a total capacity of 25MW. Like its predecessor, the project will be located off of the northern Portuguese coast — this time 20km from Viana de Castelo.

5. Hywind

Statoil, the majority government-owned Norwegian oil company, is currently in the process of building what will likely be the first floating wind farm in operation worldwide. The Hywind pilot project will consist of five turbines, each with a 6MW capacity, floating in water over 100 metres deep.

The pilot park covers an area of four square kilometres about 25km off the coast of Peterhead, Scotland. This patch of the North Sea boasts wind speeds of around 10m/second.

The Hywind turbine’s floating foundation is ballast stabilised and secured to the seabed using three mooring lines attached to anchors.