Renewables ... Bay of Fundy tests for Alstom's first tidal turbine generator

January 2, 2011

During the recent inauguration of the new premises of Alstom Hydro Ocean Energy on the island of Nantes, the French group revealed some of the key characteristics of its Beluga 9 tidal electricity-generating turbine and announced it will undergo its first tests in Canada's Bay of Fundy in 2012. The ocean energy business unit was established in 2009 when Alstom signed a technology-licensing contract with Canadian company Clean Current.

Philippe Cochet, senior vice president of Alstom Hydro & Wind, declared: 'There is a considerable potential market for tidal energy, estimated between 50GW and 100GW worldwide, of which France and the UK account for 10%. Tidal energy has some unique advantages. It is, for example, possible to predict the amount of energy that will be produced with complete accuracy, and tidal turbine generators are completely invisible once they are submerged. We are now entering an industrialisation and testing phase that will enable us to respond with a reliable solution as soon as the first calls for tenders appear.'

Nantes – with its strong French shipyard industry traditions – was adjudged the ideal base for the company's ocean energy activities. 'Our global launching-ground for ocean energy had to be in an area where there was a concentration of skills in marine activities, and that could serve France and the UK as a priority, explained Philippe Gilson, under whose direction the Nantes team is tasked with bringing to market a new generation of tidal turbine generators.

Beluga 9, intended for very powerful currents (up to 4.5m/s, or 9 knots, on the surface during spring tides) will be Alstom's first tidal turbine generator. Once mounted, it will have a diameter of 13m and a total height of 20m. The generator will be suited to sites in water depths of 30m or more. Preliminary studies are already under way for the development of a second model, intended for sites at greater depths where the tide is less powerful, with testing slated to begin offshore Brittany in 2013. OE

Wave Hub's first customer
Ocean Power Technologies, with its PowerBuoy wave energy converter, will be the first customer at the UK's new £42 million Wave Hub facility, which went 'live' in November 2010. However the facility is expected soon to be under new ownership.

The Wave Hub – a grid-connected socket on the seabed 16km off the coast of Cornwall to which wave power devices can be connected for performance evaluation – was developed by South West RDA, a regional development agency due to be abolished by the UK government by March 2012.

The system, which currently has a capacity of 20MW but was designed to be scaled up to 50MW, consists of a 12t steel chamber on the seabed in 55m of water 16km offshore, served by an armoured 33kV subsea cable supplied by JDR Cable Systems (OE September 2009). The chamber splits the main subsea cable into four 300m 'tails', each of which serves one of the four 1km x 2km berths available.

'There has been some speculation about Wave Hub's future,' said the facility's general manager Guy Lavender. 'But the future of Wave Hub and its ongoing operation are not in doubt, and the project is fully funded as we continue to seek commercial customers.

'What we don't yet know is who will own the asset when the RDA is gone, and that is being discussed. But that has no impact on Wave Hub's continued role as a vital facility for the development of the wave energy industry in the UK and overseas.'


Inter array trenching spread

A self-propelled trenching solution for the inter array power cables used to connect turbines on offshore wind farms was unveiled recently by IHC Engineering Business, part of the Netherlands-based IHC Merwede group.

The new Itat and Itat-HG trenchers, launched at RenewableUK 2010, have been designed specifically for this role and to maximise functional operability, speed of trenching and ease of mobilisation. IHC EB is also planning for the first time to make the trenching spread available for rental as well as purchase.

'Trenchers have very definite appeal to developers who would rather see them used than ploughs for inter array work close to the turbines,'explains Robbie Blakeman, special projects manager at IHC EB. 'As they are self-propelled there is no necessity for the cable lay vessel to come too close to the turbines.

'The Itat uses trenching and jetting techniques – for which we have partnered with Pharos Offshore Group on this development – while the Itat-HG, for use in harder soils, is based on our successful i-Trencher design, in effect, a “mini i-Trencher”. Both can be launched and recovered by means of a common launch and recovery system (Em-Lars), making mobilisation simpler and quicker, while also reducing the overall cost.<

'Ease of mobilisation is all important,' Blakeman adds. 'We have designed for a single lift mobilisation of the A-frame, winch and all necessary control and monitoring systems, on a common structural grillage. This grillage also serves to distribute loads into the vessel deck, removing the requirement for dedicated under-deck reinforcement.' OE




In brief

Tidal energy specialist Marine Current Turbines is targeting 2013 to install Scotland 's first tidal energy farm. The company, which designed and deployed the world's first commercial scale offshore tidal stream energy system in Northern Ireland's Strangford Lough (OE March 2010), is investigating the feasibility of a tidal farm in Kyle Rhea, a strait of water between the Isle of Skye and the Scottish mainland through which fast tidal currents pass 14 hours a day. The project is expected to provide the capacity to generate electricity for up to 4000 homes in the Highlands & Islands.

Mitsubishi Heavy Industries, through its subsidiary Mitsubishi Power Systems Europe, is to invest up to £100 million over five years in a new Scottish R&D centre with the aim of developing 'a world leading offshore wind turbine with a high degree of technical innovation'. The announcement included the acquisition of Edinburgh University spin-off Artemis Intelligent Power.

Narec has appointed McNulty Offshore Construction to carry out preconstruction services for the UK's offshore demonstrator monitoring platform works, with an expected construction value of between £4-6 million. The platform will be used to collect the necessary environmental data to inform the development, construction and operation of the demonstration site which, when completed, will enable turbine manufacturers to demonstrate their prototype wind turbine generators and foundations in the North Sea. The plan is to have the new Blyth facility in place by summer 2011.

C-Power has received over 850 million of financing for the second and third phases of its offshore 325MW wind farm at Thornton Bank, 30km off the Belgian coast. Installation of 48 jacket foundations, 48 REpower 6M wind turbines, laying of infield cable and a second 150kV export cable, plus an offshore high voltage substation, will be carried out 2011-13. 

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