Renewable energy from the sea

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Energie uit de zee

‘The currents here are crazy, and you get high winds and big waves too. We need to time this crossing just right’, Ivar warns. We have sailed from Norway to the Shetland Islands in the far north of Scotland. Unlike our time in Scandinavia, we need to take careful account here of the tides and currents. This is also a nautical area notorious for its high winds.

The Scots should be able to generate no less than 1.2 gigawatts from tidal and wave power by 2020. Ivar Smits Ivar Smits Skipper

Challenging sailing conditions

Our plan now is to sail from the Shetlands to Kirkwall, the capital of the Orkney Islands. We study the wind forecast and the tidal flows. Although there are normally six hours between high and low tide, the timing and strength of the currents vary locally due to geological conditions. Tidal currents are nevertheless predictable, as the phases of the sun and moon are known. Tide tables for specific locations tell us, for instance, that things get hairiest in the straits between islands. That’s one wild-water ride we could do without!

We plan our departure so that we will have the current with us and will arrive before the next depression turns up, bringing high winds. These can whip up towering waves that pose a real danger to sailing vessels. Our route takes us through the straits between islands, where the current gives us added impetus. We arrive just before the tide turns and a low-pressure system approaches. Later, lying in our bunks, we hear the wind gusting around the boat. These extreme conditions make it a little tense for us, but it turns out they are very good indeed when it comes to generating renewable energy.

The power of water

David Flanagan comes to meet us the following day at Kirkwall harbour. David is the press officer for the local council and he shows us around Mainland – the largest of the seventy islands that make up the Orkney archipelago. We pass small villages and emerald green, rolling fields of cows and sheep. But the pleasant, rural atmosphere is deceptive: when it comes to renewable energy from the sea, Orkney is the epicentre of the latest developments. They use the rough conditions here to generate electricity from tidal flows and waves.

Orkney is located to the north of the Scottish coast, on the far side of a narrow strait called the Pentland Firth. The North Sea lies to the east and the Atlantic Ocean to the west, giving the forces of nature free rein here. Waves in the Pentland Firth can rise to eighteen metres and currents of no less than sixteen knots have been measured. There is virtually no better place to generate renewable energy from the sea.

It happens underwater

The European Marine Energy Centre (EMEC) takes full advantage of these conditions. It manages five test locations in the Orkneys and provides connections to the power grid. The organisation also supports research and provides regulatory advice. Businesses involved with the development of tidal or wave power can use EMEC’s facilities. Generation occurs underwater. David gestures towards the sea: ‘That’s where it all happens’. We look at each other. Surely we haven’t come to Orkney just for a view of the ocean?

But we’re in luck: several large turbines are visible from land. Close to the harbour, the SR2000 is ready to be hooked up to the power grid. The 63-metre-long installation is the world’s most powerful tidal turbine, capable of generating about two megawatts – enough to power a thousand homes.

There are other turbines further along. They resemble a series of connected torpedoes with horizontal propellers between them, like something out of a science-fiction film. The companies that developed them are testing the turbines here underwater with a view to deploying them on a large scale.

Talking business in the pub

That evening, we talk to Stuart Allison, who we’ve arranged to meet in the pub at the harbour. He is the council officer responsible for Orkney’s economic development, in which renewable energy is one of the most important pillars.

‘The local authority and the Scottish government are funding research into the generation of tidal and wave energy and its commercial use’, Stuart tells us over a pint of local beer. The ‘Crown Estate’ – the UK government department that manages the seabed – has designated ten sea areas where electricity can be generated from the tides and waves. Companies can apply to lease them. ‘They should be able to generate no less than 1.2 gigawatts from tidal and wave power by 2020.’

Energy companies have already got down to work: the first turbine for a large-scale tidal power project was attached to the seabed during our stay. It works like an underwater windmill. Since water is denser than air, the installation can generate energy even at low speeds. The plan is to install 269 turbines. The know-how that Scots have built up in the offshore oil industry will come in very handy, and the new business is creating lots of jobs: a whole raft of ancillary firms have also set up in the Orkneys.

From experiment to fully-fledged energy source

It all sounds very promising, but how quickly could this type of power generation be applied on a large scale? ‘The main focus is on tidal power’, Stuart says. ‘Sea currents – and hence the electricity they generate – are predictable, which is a big advantage.’

It sounds great, but Stuart doesn’t want us to get carried away: ‘A lot of research and technological development are still needed to build installations that work well and can cope with the rough and salty conditions in the sea. We also have to take account of the potential impact the installations will have on marine life and shipping. Thanks to the substantial investment that’s been made, the large-scale application of tidal energy is becoming commercially attractive. Generating electricity from waves is less well developed and isn’t profitable enough yet to be exploited commercially.’

Stuart stresses the crucial importance of effective public-private cooperation to successful investment in infrastructure research and technological development. His faith in the future is infectious: ‘Our test facilities and the favourable natural conditions here mean that wave power promises to become a fully-fledged energy source too.’

Respect for natural forces

We keep the Pentland Firth well to starboard as we steer for the Scottish mainland. The sea chart warns about powerful currents and breakers. But they look very different to us now: just think of the potential for renewable energy!

We had already seen the successful application of wind power in Denmark, and hydraulic energy in Norway. And we’ve discovered here too what can be achieved when government and business team up to use nature to generate renewable energy with no CO2 emissions. Which countries, we wonder, will follow these examples?

For our next blog, we’ll be visiting an eco-village on the Scottish mainland. What’s it like to live there, and what can we learn?

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