UK backs sea power with first tidal lagoon

Britain has unveiled plans to build the world’s first tidal lagoon power plant. Tidal power is set to someday provide 8% of UK energy. But will renewables will ever be efficient enough?

‘We have a wonderful opportunity to create energy from the dance between the moon and the Earth.’ These were not the words of some spiritualist leader, but the CEO of a company that this week unveiled the world’s first plans to generate power by creating tidal lagoons.

The lagoon will be built at Swansea Bay, Wales. A five-mile wall, encircling an area of water, will stretch two miles out to sea. Ninety turbines will be built into the wall. These will be powered by the weight of the water, creating electricity as the tide rises and falls and water passes between the lagoon and the open sea.

The company behind the plans intends to build more lagoons in Wales, Cumbria and Somerset. Between them, they will aim to provide 8% of the UK’s electricity over the next century.

One benefit of marine energy is that it is predictable, unlike solar and wind power. The project is forecast to generate enough electricity for 155,000 homes, which, annually, is equivalent to all of Swansea.

It’s also hoping to save hundreds of thousands of tonnes of carbon dioxide, helping the UK meet its carbon reduction targets and reducing our fossil fuel dependence. ‘If it helps us to close Aberthaw power station — one of the most polluting in the world — it’ll be a good thing’, says Director of Friends of the Earth Cymru.

The UK has a high tidal range, and Tidal Lagoon says over time its tide-generated electricity will be cost-competitive with nuclear and gas, not to mention the economic benefits, too.

But there is a major downside: the price. The Swansea Bay lagoon will cost £1bn, which would be funded by electricity bill-payers. The project has been called ‘appalling value for money’ by consumer charity Citizens Advice.

This isn’t the first time renewable energy has been labelled inefficient — especially wind and solar power, which require certain weather conditions to generate power and are expensive to build. The levels of energy they create, some feel, don’t justify the spend.

Rethinking renewables

Renewable energy sources like wind and wave turbines are simply ‘too inefficient and expensive to meet our energy needs’, one journalist recently said. The idea that they can fulfil our energy needs is fanciful. Instead of spending billions of pounds on the pursuit of a fantasy, we should pursue other alternatives, such as nuclear power.

It’s true that renewable energy sources are not efficient yet, admit their supporters. But increasingly they are becoming more so. Tidal Lagoon says the project will be expensive to begin with, but much cheaper in the long run. The more we invest in renewable energy now, the more likely it is we’ll be able to depend on it when oil and gas run out.

You Decide

  1. Can renewable energy save the world from the most devastating effects of climate change?
  2. Can governments force technological progress, or do the most important breakthroughs happen naturally?


  1. Over the course of a day, write a diary entry recording every time you use energy, for how long and how: watching television, boiling the kettle, etc. Are the results surprising?
  2. In groups, draw a diagram of the planned tidal lagoon plant, annotating with explanations as to how it works.

Some People Say...

“The future is green energy, sustainability, renewable energy.”

Arnold Schwarzenegger

What do you think?

Q & A

Don’t we already have marine energy in the UK?
The SeaGen tidal stream generator has been operating in Northern Ireland since 2008, and is the world’s first large scale commercial generator of its kind. There are also several wave and tidal stream projects underway elsewhere. In Scotland, MeyGen’s tidal stream project is currently in the works, and hopes to be ‘one of the most energetic sites in Europe’.
Could we ever get all of our energy from renewable sources?
Around 30 nations across the world get 20% of their energy from renewable sources. A 2009 study suggested that it is both possible and affordable for the world to convert to 100% renewable energy in the next five years, but say lack of political support is one of the main barriers to this.

Word Watch

The Welsh word for ‘Wales’; Cymry means ‘Welsh’. Wales has its own language — Cymraeg — and around one fifth of the population can speak it.
Tidal range
The vertical difference between a high and low tide. The UK often sees tidal ranges of up to 15 metres in the Severn Estuary between England and Wales.
Nuclear fission plants generate power by splitting uranium atoms, thus creating an enormous amount of energy. However, this type of reaction also produces waste, and can be horrifically destructive if it is not carefully controlled. Some scientists hope that we may one day master a far more clean and efficient type of nuclear power called nuclear fusion.
Tidal Lagoon Ltd hopes that its plans will kickstart an industry that will eventually deliver tens of billions of pounds to the national economy. But in the more immediate term, it will provide jobs for the Swansea area.
All renewable energy projects are subsidised by the government giving the producer a guaranteed price. This is known as a strike price.


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