Harnessing the energy of the ocean to power homes, planes and whisky distilleries
KIRKWALL, Scotland — Ocean boosters like to compare the kinetic energy stored in the sea to a ginormous oil reserve that’s never going to run dry.
It doesn’t matter if the sun shines or the wind blows. The tides turn. You can set your watch to them. The trick is how to generate cost-effective, renewable electricity from that limitless, ceaseless motion. They’re working on the problem here on Scotland’s Orkney Islands.
When you first look at the ideas for ocean-energy devices, the whole thing does look a little … sci-fi. Underwater corkscrews. Oscillating hydrofoils. Tidal kites? Seriously.
And it gets more out there.
In Scotland, they want to plug this ocean energy into shoreside electrolyzers, which separate water (good old H20) into oxygen and green hydrogen, and use the gas bubbles to power … whisky distilleries.
And maybe someday to heat homes and schools — and power passenger ferries and planes that hop between islands.
It’s all hopeful and ingenious — and the world certainly needs some hope, as the COP26 climate summit winds down in Glasgow, Scotland, and we wait to see if there’s enough ambition to avoid potentially catastrophic warming.
It’s worth knowing, though, that the sea here is also a graveyard, with once-pioneering ocean energy prototypes now turning to rust, after much-hyped start-ups were liquidated in bankruptcies.
But after two decades of trial and error, the sector’s backers say marine energy is getting there. They say tidal machines could begin to work alongside far more developed energy systems, based on solar and wind power, within the decade.
The basic concept? Imagine taking an offshore wind turbine, with its rotor blades spun by moving air, and turning the thing upside down, dunking it into the sea, and letting the tidal currents turn the blades.
240 feet long, with a 200-foot wingspan, the turbine is the size of a Boeing 747.
Once in place, the turbine anchors itself to the channel bottom and lowers its wings.
The turbine’s blades turn in the tidal flow, powering the generators on the wings.
As the tide turns, the rotors simply reverse, drawing power from the flow constantly.
The wing generators produce electricity that charges the turbine’s large batteries.
The electricity also flows from the turbine to onshore power distribution centers through a large cable.
The idea is simple; execution, less so. These devices — and their computers, turbines and hydraulics — must survive in some of the harshest conditions on Earth.
Neil Kermode, managing director of the European Marine Energy Center (EMEC), says tidal energy is poised to help Britain deliver on its promise to go net-zero on carbon emissions.
“The R&D has shown it works and industry has shown it can do this,” he wrote in an appeal to the electricity regulators to adapt to new technologies like ocean power.
“This opportunity is right here,” he said, “right now.”
Kermode lives in the Orkneys. About 20 of the more than 70 islands are inhabited. Total population: 22,000. It is not most people’s idea of a beach vacation. It’s all gray stone houses and Neolithic stone circles — and dreich weather. But for ocean technologists, it’s near perfect: fierce winds, wicked tidal races and endless sets of just-right waves.
Developers have been towing their ideas up to Orkney because the islands are home to the EMEC, dedicated to wave and tidal power, with a test site set up to run trials on blue-energy machines. The site also allows for some projects to be plugged into the national electricity grid or for their excess juice to be made into hydrogen.
Scotland is among a handful of such sites. Competitors are at work along the coasts of China, France, South Korea and Canada. In the United States, they’ve done demonstration projects in Maine and Washington state, and one in the East River in New York City.
But the Orkney Islands have hosted 34 experimental marine energy devices, more machines than anywhere else in the world.
Over the years, the sea passages between the islands have seen wave and tidal machines that bring to mind steel manta rays and undulating sea snakes. One early device looked like a giant propeller riding an elevator.
Some couldn’t keep water on the right side of the hull, and sank. Other developers proved their concepts but ran out of money before they could make the leap from experimental to commercial.
There are three machines in the Orkneys today.
One is a prototype wave energy converter called “Blue X,” by Mocean Energy. The thing is a 65-foot hinged raft that resembles a floating double-ended kitchen spatula. As waves raise and lower the machine, the rocking motion of the hinge captures the energy of the ocean and the turbine converts it into electricity. The device can be operated wirelessly, with commands sent from shore.
Mocean Energy Managing Director Cameron McNatt said that after sea trials, the company wants to connect the device to a subsea battery, which will power a remotely operated underwater vehicle. An underwater robot could be deployed to service offshore devices related to oil, gas, wind or tides.
The Blue X is dwarfed in size by two tidal machines operating in Orkney waters. “ATIR,” from Spanish developer Magallanes Renovables, is capable of producing 1.5 megawatts of power, while “Orbital O2,” from a British firm, is rated for 2 megawatts, enough to power 2,000 homes a year.
In 2019, Magallanes founder Alejandro Marques took a Washington Post reporter out to the ATIR to scramble up on the deck and down below, as the machine bucked in the waves.
“Basically, what you see is something that looks like a boat, yes?” Marques said. “But with a big windmill hanging off the bottom.”
“And this boat isn’t moving. It’s anchored to the seafloor. What is moving,” and here he paused, “is the ocean.”
Marques said the concept of generating power for the grid has already been proved. ATIR and other devices have sent a trickle of electrons to the shore. What needs to happen, he said, is for the price of producing that power to become more competitive, which he called “inevitable over time.”
The latest tidal machine to arrive in Orkney is Orbital O2 — 240 feet long, weighing 650 tons, as big as a floating jumbo jet. The thing looks like the Beatles’ yellow submarine.
Orbital’s device was towed out to the Fall of Warness test site in July and anchored to the seafloor by four chains, each capable of lifting 50 double-decker buses. The anchors have to be strong, because the tidal currents here are some of the fastest on Earth — a river of ocean water moving one way and then the other, to almost 8 knots, or 9 miles an hour, on spring tides.
On the O2, the turbines are hung on a pair of sea wings, which carry pitched rotor blades, with a huge 65-foot diameter, that can capture the tide as it runs in both directions.
The wings and turbines can be raised to the surface for maintenance, so repairs don’t require ocean divers, submersibles or a tow back to the dock. Basic maintenance can be done between the tides, its designers say.
In May, Britain’s Prince William and Catherine, Duchess of Cambridge, were shuttled out to visit the O2 — courtesy of the Royal Navy — and christened the device with a splash of Scapa whisky.
Oliver Wragg, commercial director at Orbital, knows many ocean energy experiments have come and gone. He stressed that the O2 is more than a prototype. “It’s designed to produce electricity for use,” supplying power to the national grid and shoreside experiments in green hydrogen power. The device is set to remain in Orkney waters for 15 years, he said.
Wragg imagined what it would look like to see hundreds of the devices arrayed together in the seaway, just as offshore wind farms are today.
He does a rough calculation. Assume the global tidal energy market today is 100,000 megawatts, enough to provide electricity to 100 million homes. To manufacture and maintain, say, 50,000 machines generating 2 megawatts each — at $3 million a machine — might cost $150 billion, he told The Post.
Nailing down comparative costs of generating a megawatt hour of electricity is complex, but Wragg estimated that once a few hundred tidal machines were out at sea, the blue energy might be cheaper than nuclear power.
The British government is intrigued. Orbital was one of 12 companies invited to an investment summit hosted by Prime Minister Boris Johnson in October, designed to showcase the most innovative green technologies operating in Britain.
The experiments in Orkney offer a look at how the whole array might be interconnected — a real-world beta test of an integrated, renewable energy future in which electricity created by offshore wind and ocean power is used to produce green hydrogen.
Hydrogen produced by fossil fuels is already widely used. Green hydrogen is an industry still in its infancy.
The idea is to generate electricity from the rotor blades of turbines, spinning up in the air and below the sea, powered by wind and water, to produce electricity for the national grid, and to siphon some excess power to shoreside energy plants, to split ordinary water into hydrogen and oxygen, through a process called electrolysis.
These bubbles of clean green hydrogen gas can be — and already are in pilot programs — stored in fuel cells or tubes, which can be transported by delivery truck.
Green hydrogen already powers a small fleet of cars. Prototypes are coming in the next year to run ferries, at first with green hydrogen as auxiliary power, alongside diesel. And at the airport here in Kirkwall, engineers are preparing to run trials of electric and hydrogen-powered airplanes. The Scottish government says it hopes to create in the Orkney Islands the “world’s first zero emission aviation sector.”
One of the first projects aims to launch a 350-mile hydrogen-electric test flight of a 19-seat piloted aircraft — set for sometime in 2023.
Last year, Orkney’s sea pioneers wrangled a meeting with the British prime minister on his visit to Edinburgh. As part of their pitch, they proposed that Orkney become an “innovation free port,” to be given the regulatory and fiscal flexibility to explore new technical and structural solutions.
Gareth Davies, chair of Aquatera Group in Orkney, told Johnson that 25 percent of Britain’s total electricity could be supplied by northern Scotland’s abundant wind, tide and solar resources, if they were harnessed. Today, less than 1 percent of the potential is being exploited.
Asked for the prime minister’s reaction to that, Davies told The Post. “I think he was surprised.” He added, “And inspired, too, by the ambition.”