Heatwave: How Orkney is leading a tidal energy revolution | Environment

On a small passenger boat about 10 miles north of Kirkwall, Orkney, where the Atlantic Ocean meets the North Sea, a huge yellow structure appears. This is the most powerful tidal power generator in the world, the O2 from Orbital Marine Power. His shadow quickly eclipses the small ship.

Today, the generator turbines are raised above sea level for maintenance. It’s hard to fathom the scale of the O2 until a worker appears, a tiny stick figure against the towering turbine.

Map of the Orkney Islands

Orkney, chosen as the seat of the European Marine Energy Center (Emec) for its combination of strong tides and waves as well as its connection to the energy grid, has become a hub for tidal energy innovation. Alongside the Scottish company Orbital, the Spanish company Magallanes is also testing at Emec and the American company Aquantis has just signed a six-month demonstration programme.

The Orbital O2 at the Emec Fall of Warness test site. Photography: Orbital Marine Power

Tidal power, although not yet widely commercialized, is seen by many as the next frontier of global renewable energy. It is the only source of renewable energy which comes from the attraction of the moon on the Earth. “Unlike other renewables that depend on, say, the sun or the wind, tidal resources are predictable and continuous,” says Professor AbuBakr Bahaj, head of the energy and climate change division at the University of Southampton.

Harnessing wave energy can be done in three ways: tidal booms, in which the turbines are attached to a dam-like wall; tidal lagoons, where a body of water is surrounded by a dam-like barrier; and tidal current, where the turbines are placed directly in fast-flowing bodies of water.

Only tidal barrages are in commercial use – notably at Lake Sihwa in South Korea and La Rance in northern France – but it is tidal technology that is being tested in Orkney. Tidal current is cheaper to build and has less impact on the environment than dams, which alter tidal flow and can affect marine life and birds.

Tidal power alone could provide 11% of the UK’s current electricity needs, according to a 2021 study from the University of Edinburgh.

Harness the tidal energy graph

Despite its promises, progress has been slow. Aboard the boat, Emec’s Lisa MacKenzie tells a now infamous story about Britain’s renewable energy sector. In the 1980s, Orkney was home to experimental wind turbine technology that could have seen the UK become a world leader in the sector. But the government failed to invest – and Denmark and Germany rushed to monopolize the market.

“Wind power was the UK’s loss and we lost it,” she says. “Now tidal power is ours to lose. We can’t let that happen again.”

In Orkney, testing aims to reduce the costs and risks of tidal power to make it commercially viable. “We have some of the best conditions in the world to test new technologies,” says MacKenzie. “More ocean energy converters have been tested here than at any other site.”

Orbital’s O2 turbine, deployed at Orkney’s Fall of Warness test site in July last year, is the third iteration of its tidal technology. This is the version the company hopes to release. It consists of a 74-meter floating structure with a two-bladed turbine submerged on each side. An undersea cable connects it to the local onshore power grid, where the energy it produces can meet the needs of around 2,000 homes each year.

Orbital 02 turbine blades
Orbital 02 turbine blades being submerged under the waves. Photography: Orbital Marine Power

“Any new technology in any space is more expensive than the market, so we can’t compete with mature production technologies,” said Andrew Scott, CEO of Orbital Marine Power. “What we need is market intervention to level the playing field.”

The UK is seen as a world leader in the development of tidal energy technology, but while the government provided limited support to the sector from 2008, it was phased out in 2016. Last year , the government has reintroduced short-term support, but what is needed is a long-term view, says Scott.

“If we can’t make sure there’s going to be a long-term market, we’re still at square one,” he says. “Private investors won’t be ready to invest because you feel like the rug can be taken away from you at any time.”

Minutes from the O2 is an abandoned test bed installed by Irish company OpenHydro in 2006. The company went into liquidation in 2018, after being bought by French company Naval Energies which eventually withdrew its funding. In the same year, plans for a tidal lagoon at Swansea Bay, previously tipped to be the UK’s first commercial tidal power generator, fell apart when the government failed to secure financial support to cover the costs. energy.

This is a global challenge, says Bahaj. “The operational environment requires high specification designs and technologies, as well as specialist vessels for installation and maintenance,” he said. “All of these activities require money from developers who, unlike oil and gas, are mainly SMEs with limited financial resources. Availability of funding, including government technology support, is the main challenge limiting scale-up and cost reductions. »

Graphic of orbital O2 turbine.
A graphic showing the Orbital O2 in action. Photography: Orbital Marine

Some governments are reacting. In 2020, the Canadian government announced a $28.5 million investment in floating tidal power developed by Scottish company Sustainable Marine in the Bay of Fundy, home to the world’s most powerful tides. In May, she delivered the first floating tidal power to the Nova Scotia power grid.

The Faroe Islands are also home to ambitious investments in tidal currents. Under a 2018 deal, Swedish developer Minesto will install and operate two grid-connected tidal units and the islands’ main electricity company, SEV, has committed to buying the power. At the time, the deal was hailed by Minesto CEO Dr Martin Edlund as playing “an important role” in the Faroe Islands’ planned transition to 100% renewable energy by 2030.

Orbital’s Scott wants the UK to take an equally ambitious approach to tidal power. “We have the ability to develop an indigenous industry here, an industry that can help with the net zero, the upgrading program, the just transition,” he says. The O2 was built using a UK supply chain that has generated around 60 jobs, he adds. “The industry does not need to become massive and we can make a very significant contribution.”

Back on the boat as it cruises around the Orkney Islands, MacKenzie watches for orcas, which had been spotted near the O2 earlier in the day.

As tidal technology develops, some scientists have raised concerns about potential effects on marine life. MacKenzie says marine mammals and fish are very good at avoiding boats and other structures, and research at Emec’s test sites has shown little impact on wildlife. Some studies have suggested that tidal and wave systems may even have a positive effect on marine life, acting as artificial reefs.

The vessels required for installation and maintenance generate potentially disruptive noise, but the tide itself, in these rough seas, is considered louder than the turbine. Turbine blades can present the greatest dangers, but research suggests their effects are rare and mostly non-lethal.

With the ability to generate large volumes of predictable, renewable energy, some experts believe tidal power could play an important role in the global energy mix.

“There is global interest in tidal currents and with the current rise in gas and electricity prices, tidal power is likely to compete favorably,” says Bahaj. “In a way, the future looks brighter than a year ago.”

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