Strangford Lough Tidal Turbine, United Kingdom
The world's first commercial-scale tidal turbine was commissioned in Northern Ireland's Strangford Lough in July 2008. The 1.2MW SeaGen project was developed by Marine Current Turbines (MCT). The project, comprising of two 600KW turbines, required a total investment of £12m.
The project reached an important milestone in September 2012 by producing up to 5GWh of power since its commissioning. This is equal to the power required by 1,500 households annually. The milestone indicates the completion of the demonstration phase of the project.
Finance for the Strangford Lough tidal facility
The project was partly funded by the UK Department of Trade and Industry (DTI) and the UK Government granted £5.2m towards it. Northern Ireland Electricity provided funding of £500,000 as part of NIE Smart (Sustainable Management of Assets and Renewable Technologies), which encourages the development of renewable power and energy efficient alternatives throughout Northern Ireland.
In 2011, the project attained the UK Government's operating performance criteria, qualifying it to benefit from the Marine Renewables Deployment Fund established by the Department of Energy and Climate Change.
SeaGen tidal energy turbine project details
SeaGen was installed in Strangford Lough in May 2008. It was towed to the mouth of the Lough by a barge. The turbine as a whole weighs 1,000t, and is 43m wide from tip to tip. Designed by engineer Peter Fraenkel, the rotors drive a generator that sends energy along a cable that then links into the national grid across the Lough in Strangford village.
Built at Belfast's Harland and Wolff's shipyards, the birthplace of the Titanic, SeaGen took around 14 days to install, with the system literally being bolted onto the Lough's bed. SeaGen briefly delivered 150KW of electricity into the grid while it was being commissioned in July 2008.
Two turbine blades were damaged during commissioning, and were removed from the hub for inspection. The damage is thought to have been caused by a fault in the control system, and MCT reported that it came from a combination of circumstances that can only arise during commissioning. Eventual operation of the project was, however, unaffected and the two turbines reached their full capacity in November 2008.
SeaGen has a mobile cross arm on a single supporting pile 3m in diameter and 9m above the average sea level. The twin rotors begin to generate electricity once the tide runs faster than 1m/s. At maximum speed, the tips move at around 12m/s, which is around 1/3 of the average wind turbine speed. The two rotating blades turn at 14rpm and drive a gear box system.
Grid connection of the Irish tidal plant
The project has the capacity to supply power to 1,500 homes. Irish energy company ESB Independent Energy buys the power generated by the turbines for its customers in Northern Ireland and the Republic or Ireland. The grid connection work was undertaken in partnership with Northern Ireland Electricity.
Technical challenges to tidal wind farm
The marine environment posed a number of unique technical challenges, not least installing SeaGen in an extremely aggressive tide race. SeaGen works much like an 'underwater windmill' with the rotors being driven by the power of the tidal currents rather than the wind.
Strangford Lough has a highly energetic tide race and so is recognised as one of the main tidal 'hotspots' in UK and Irish waters. Other areas are the waters off Anglesey, the Pentland Firth and the Channel Islands.
MCT established a £2m programme to monitor SeaGen's environmental impact, involving scientists from the Queen's University Belfast and from the Sea Mammal Research Unit (SMRU) at St Andrew's University.
The programme included the presence of a marine mammal observer on SeaGen at all times during the commissioning phase, where SeaGen only operated during daylight hours, to observe how it interacted with the Lough's marine life.
There was also a sonar system, which monitored seal movements, operated by SMRU and partly paid for by the nPower juice fund.
The project was given an environmental all-clear in January 2012 under the Environmental Monitoring Programme led by the environmental consultancy, Royal Haskoning.
Project planned for Anglesey
Atlantis Resource Corporation redeployed the AK-1000 tidal turbine at the European Marine Energy Centre (EMEC) in Orkney, Scotland, in August 2011.
It is claimed that tidal power could supply up to 10% of the UK's energy within ten years, and SeaGen is the world's first commercial tidal stream energy generator. It is more than four times as powerful than the world's second most powerful tidal current system, the 300KW SeaFlow that was installed off Lynmouth on the north Devon coast more than five years ago.
The system will act as a prototype for even larger installations. Based on the Strangford Lough experience, the company plans to scale up the technology to build a 10MW tidal power farm within the next three years and wants to have 500MW of tidal capacity by 2015. MCT's next project, announced in February 2008, is a joint initiative with nPower renewables to develop a 10.5MW project using several SeaGen devices off the coast of Anglesey, north Wales.
The company is also investigating the potential for tidal energy schemes in other parts of the UK, and in North America.
MCT is based in Bristol, England. The company was established in 2000 and its principal corporate shareholders include BankInvest, ESB International, EDF Energy, Guernsey Electricity and Triodos Bank. Siemens acquired around 10% interest in MCT in February 2010. In February 2012, Siemens increased its stake to 45%.