The Sunday Telegraph - Business & Money
Tidal power turbocharges hopes for shift to renewables
Waves don’t suffer the issues that the energy crisis has highlighted with wind, says Alan Tovey
It might sound like a feeble excuse at a time of rocketing prices and global economic chaos, but the country’s current energy crisis can to a large extent be explained by blaming the weather.
As the UK races towards a more renewable future, with 28pc of power generated by clean energy sources last year, keeping the lights on is ever more reliant on sunshine and a stiff breeze.
Unfortunately, conditions this year have been far from ideal. In July, average wind speeds in the UK were slower than usual at just 5.7 knots.
Solar farms, responsible for a smaller share of power generation, are less effective in cloudy skies and can suffer in Britain’s uncertain climate.
However, there is one other abundant natural resource surrounding Britain which operates like clockwork and generates huge amounts of energy. The tide is a reliable, predictable source of natural power – and one that the UK is ideally placed to harvest.
“As long as there’s a sun, moon and ocean, we will always have tides,” says Rob Stevens, chairman of Perpetuus Tidal Energy Centre, which is developing a site off the Isle of Wight using turbines driven by the movement of the sea.
“You can predict the tides 100 years out. And as an island nation, we can get 50pc of the tidal power in Europe.”
The principle behind tidal power is simple. Water movement, driven by celestial forces or captured in lagoons and then released, moves through turbines which are either floating or fixed in place. This well understood technology generates electricity which is then fed into the grid.
The Government has estimated that about 10gigawatts of electricity could be produced by harnessing tidal power in the UK, with its potential higher in the winter when energy demand is greatest as tides are stronger then – enough to power about 3m homes. To put that in perspective, the UK’S current generation capacity from all sources is about 75GW.
Water is also more than 800 times denser than air, so its movement generates more power than wind and smaller or fewer turbines are needed as a result. But if tidal is so reliable and simple, why hasn’t it been done before?
“It’s economics and short-termism,” says Stevens, a former head of the Royal Navy’s submarine service.
He says when offshore wind was first being considered, the projected cost was £200 per megawatt hour. Government backing, economies of scale and technological developments have since cut that by as much as 75pc.
The initial estimated cost of tidal power was £350 per megawatt hour, says Stevens, so investors went for cheaper wind instead.
Some companies have nonetheless persisted with their tidal dream.
According to figures from the Offshore Renewable Energy Catapult (Orec), about two dozen tidal energy businesses are active in the UK. Private investment in the industry has exceeded £500m, with £300m of taxpayer support.
Simon Cheeseman, head of tidal and wave power at Orec, says Britain is positioned to be a world leader.
“We’ve had support from government, we’ve got fantastic expertise, we’re brilliantly located,” he says, adding that with 30 megawatts of tidal power generation projects installed in the UK to date, the country is ahead of any other.
“What’s held it back is that it has been expensive to develop,” Cheeseman says. “We can test on land but you only really get to understand at sea.
“You’re operating in areas with high flows of water, with only a few hours of ‘slack’ water to work, there are small weather windows, offshore vessels are expensive. But the technology is now understood, reliable and working.
“Perhaps we over-claimed in the early days about how easy it would be, but a few tenacious British companies have stuck with it and have cracked the problems, such as corrosion and how to get the power ashore.”
That tenacity has paid off. According to Orec’s analysis, the cost of tidal power will fall to £90 per megawatt hour once 1 gigawatt of generating capacity is installed worldwide. That puts it in the same price bracket as energy coming from UK nuclear plants.
Cheeseman estimates that getting the first gigawatt will cost £1bn. He calculates that if the UK installs 100MW of tidal power a year as part of a growing global market, by 2040 the industry could be contributing £4bn a year to Britain’s economy.
Up to 14,500 jobs would be created either building or maintaining offshore tidal power systems – many of them in coastal or remote areas which the Government is keen to level up.
Kwasi Kwarteng, the Business Secretary, has indicated some support for tidal power. Speaking after the Government’s 10-point plan for a “green industrial revolution” was launched, Kwarteng said he believed “the only way we can get to net zero by 2050 is through innovation. Tidal technology is part of that innovation. The only caveat is that it cannot come at any cost”.
Ministers set aside £31m last month to fund new energy technologies such as tidal and wave power as part of their latest round of the contracts for difference scheme to support investment for low carbon energy.
But this may not be enough. Cheeseman wants a ring-fenced amount set aside for tidal turbines, rather than forcing the technology to compete against rivals that are potentially cheaper but flawed.
The reliability of tidal power could create savings in other areas, he says, as it provides a steady baseload into the grid. This would mean that less money needs to be spent on back-up power generation such as gas and nuclear to support intermittent generation from wind and solar. Because they operate in fast-moving water, nearby seabeds are naturally scoured to rock in the best places to site turbines. Industry lobbyists say that the local environment is not affected as a result.
Stevens says interest has picked up in the wake of the energy crisis, while Cheeseman warns against the UK missing out on an opportunity to be a world leader in a new technology. “The technology is ready, it can be made in the UK, it’s great for levelling up,” he says. “We just need to get the market conditions right for tidal power in the way we created a market for wind.”
‘You can predict the tides 100 years out. As an island nation, we can get 50pc of the tidal power in Europe’