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UK urged to push ahead with world-first tidal lagoon power plant

UK urged to push ahead with world-first tidal lagoon power plant. Science & Technology World Website

The UK government has been urged to “stop dithering” and push ahead with a world-first tidal lagoon power plant.

Speaking ahead of the publication later today of a government-commissioned report into the role tidal lagoons could play in the energy mix, shadow business secretary Clive Lewis said an initial scheme in Swansea Bay should be built.

“We have high hopes that tidal energy will get cheaper fast, as we’ve seen in other renewable technologies,” he said. “The Government has repeatedly delayed this project, despite Labour backing it months ago. It’s time to stop dithering and get it built.”

The review to be published today is expected to back the scheme.

Predictable energy

Backers of the project say it could produce predictable low-carbon energy over a long time-frame and provide economic opportunities to boost the supply chain, regenerate the local area and develop an export business.

Juliet Davenport, chief executive of Good Energy, one of the first investors in Swansea Bay Tidal Lagoon, said: “By kicking off a British tidal lagoon industry we are presenting the world with another awesome low-carbon option, and it’s British know-how that will be called upon should other countries look to take up that option.”

“Tidal lagoons are a brilliant way for Britain to diversify its energy mix and keep the lights on. They will also create a whole new industry and thousands of jobs as well.”

Environmentalists backed the development of the clean technology, but warned that considerations such as the impact on the wildlife-rich Severn Estuary must be taken into account.

Impact on sealife

Haf Elgar, acting director of Friends of the Earth Cymru, said: “A tidal lagoon in Swansea Bay could play a significant role in generating clean energy in Wales, and will be an important test of this exciting new power source.”

“Tidal lagoons could have a big future, however it is crucial that any potential impacts on wildlife and the wider environment are properly considered and addressed before any new developments are given the go-ahead.”

“New clean energy sources are important, but it is crucial that the Government also ensures that adequate investment is targeted right now in low-cost renewable technologies, like solar and wind, that already generate a quarter of UK electricity.”

Joan Edwards, from the Wildlife Trusts, said: “The Severn Estuary is a remarkable and unique cathedral of Britain’s natural heritage. It has the second largest tidal range of any estuary in the world.

“Any major development within it risks dramatically affecting the fish and birds and other wildlife that depend on it. We recognise the urgency for renewable energy development but its overall environmental impact must be assessed.”

What are tidal lagoons?

They are U-shaped breakwaters built out from the coast, with a bank of turbines turned by water to harness the tides to generate renewable electricity.

How do they work?

They capture a large volume of water behind the breakwater which is then released to drive the turbines.

As the tide comes in gates which are shut in front of the turbines hold back the water and create a difference in water levels. Once a significant height difference is reached, the gates are opened and water flows through the turbines into the lagoon, driving them to generate power.

The process is repeated in reverse as the tide goes out.

Where are they?

Nowhere, yet. There have been efforts to develop a scheme of around 320 megawatts (MW) – enough to power 155,000 homes – in Swansea Bay, which developers say would be a world-first tidal lagoon power plant.

Developer Tidal Lagoon Power wants Swansea Bay to be a proof-of-concept project, opening the way for a series of lagoons around the coast, costing less due to economies of scale and meeting 8 per cent of the country’s power needs for 120 years.

Why Swansea Bay?

The Severn Estuary has the second highest tidal range – the height difference between high and low tide – in the world, and at Swansea Bay it is around seven to nine metres, making it ideal for harnessing tidal power.

Why hasn’t technology been developed for the Severn before?

There has long been a debate about ways of harnessing the tidal power of the Severn, most frequently a tidal barrage which would stretch across the estuary at some point between Wales and south-west England.

It has been repeatedly rejected as too costly and environmentally damaging.

What are the benefits of a tidal lagoon?

A lagoon would not block the estuary like a barrage, and it would generate low-carbon electricity in a predictable way according to the tides over a long time-frame.

The review for the Government said it could be cost-effective compared with other low carbon technologies such as nuclear power, help the UK meet its targets to tackle climate change and provide an economic boost to the supply chain and local area.

Any downsides?

There have been concerns about costs, with the Swansea Bay project needing capital of £1.3 billion, although the review seems to lay those to rest to some extent.

Such a large development in the Severn Estuary – a wildlife-rich region with multiple protected areas – could have an impact on nature and habitats, as well as on other commercial interests in the region.

The review has called for the Swansea Bay project to be operational before the go-ahead is given for any more, larger lagoons, so the impacts could be studied.

What would the costs be?

An initial smaller project, such as the one in Swansea Bay, would be about 30 pence per household per year. A large-scale project would be less than 50 pence over the first 60 years, according to former energy minister Charles Hendry, who led the review.

World's largest tidal energy power plant (269 turbines) to begin construction in Scotland

World's largest tidal energy power plant (269 turbines) to begin construction in Scotland. Science & Technology World Website

The MeyGen tidal project in Scotland will be the largest tidal power plant in the world once operational. Atlantis, the Australian company that is building it has just received the green light from the government and construction should begin this month. The tidal project will be located in an area that lies in the channel ("Inner Sound") between the island of Stroma and the north easterly tip of the Scottish mainland, encompassing almost 3.5 square-km of fast flowing water.

When MeyGen is fully operational, it should have 269 turbines that produce 398MW of clean energy, generating enough electricity to power 175,000 Scottish homes.

There are currently two suppliers working to make the turbines, and they both have deployed 1MW pre-production prototypes. The turbines used in the actual project should be a little bigger based on my back-of-the-envelope math (if the capacity number is 400MW and the number of turbines is 269, each turbine should have a capacity of about 1.48MW).

Atlantis has raised USD $83 million to finance the first phase of the project, which will be the installation of 4 1.5MW turbines in Scotland’s Pentland Firth. The demonstration phase is planned to scale up to 86MW. The company expects the first electrons to be delivered to the power grid in 2016, and to have about 60 turbines installed and delivering power by 2020.

This is an interesting project, because it'll help show if tidal power can be more competitive than other forms of wave power with the juggernaut that is solar power, and to a lesser extent, wind power.

Japan to launch world’s first hybrid wind-tidal plant

Japan to launch world’s first hybrid wind-tidal plant     Science & Technology World Website

According to MODEC, a Japanese engineering firm, the world’s first hybrid wind-current power generation plant will be installed off the coast of Japan later this year.

The combination is expected to help increase stability and efficiency of power production from alternative sources. The 60-meter floating apparatus comprises a windmill above the waves and a tidal waterwheel beneath the surface, they announced Thursday.

This coupling could prove useful if an earthquake or other disaster cuts off the external power source that a typical windmill needs to boot up. After machinery with an output capacity of 500 kw is tested for around one year, power transmission is expected to start in fall 2014.

The equipment, to be installed around 1 km northwest of the city of Karatsu, may be leased to local fishermen who could sell the power, according to the company and the prefecture.

The new system, descriptively named the SKWID (Savonius Keel and Wind Turbine Darrieus), consists of three main parts. Standing above the water line is a Darrieus vertical-axis wind turbine. On the opposite end of the station, submerged in the water is a Savonius tidal turbine. Connecting these two systems is a central platform that’s home to a gearbox and generator which creates electricity from both the wind and tide that surround the platform.

What’s most remarkable about this system is its ability to use both wind and tidal inputs to generate power simultaneously. According to a MODEC because of the Darrieus turbine’s design the SKWID can catch “twice as much wind when compared to the circular swept area of typical onshore wind turbines.” Couple that with a Savonius current turbine that can “harness any weak current” and is “harmless to the marine ecosystem” and you have one of the most sustainable, efficient, marine friendly power stations ever created.

Now some might wonder if placing a power station on the ocean’s turbulent surface is good idea. But before you start having visions of inverted SKWID units littering the worlds oceans know that MODEC has that problem covered. The platform structure that houses the heart of the station “supports the power generation assembly via a set of rubber mounts like a gimbal to isolate the power generation assembly from the wave motion.” To further tie the station into place the Savonius current turbine also acts like a ballast giving the SKWID self-righting capabilities.

Sometime next fall MODEC’s first SKWID unit will become operational. The company believes that each unit could generate enough power for about 300 households. Although that represents an impressive beginning MODEC’s SKWID units will have to demonstrate greater power generation if the technology is to scale effectively. Still, SKWIDs could be used to power facilities like oil platforms and small island communities with no problems whatsoever.



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