There are few more satisfying moments in an editor’s life than when he or she sees their work off to the printer. The correspondents have filed. The copy has been subbed and the proofs have been read. Apart from the expected typo, which will emerge on the front page the moment it returns from the printer, life is sweet and it is time to repair to bed. Nothing further can be done. True, printers can occasionally get the pagination wrong, often with highly comic results. On one memorable day, this happened at the printer of a well-known, glossy pornographic magazine, which gave a new meaning to the phrase ‘ass over tit’ and cost someone a lot of money.

Either way, it is not quite the same when an editorial article praises a technology to the skies and then finds, between final proofs and printed word, that the technology in question has been blown to bits. This is what happened to the world’s first commercial scale wave power machine as the journalists drove home. For reasons still not adequately understood, perhaps a burst of massive overconfidence, the 2 MW Osprey was planted off the north coast of Scotland. It was destroyed by the waves that were meant to power it, very shortly after it was launched on the sea in August 1995. The cause appears to have been that the steel ballast tanks intended to fix it to the floor had not yet been filled before it blew away.

To add insult to injury, Osprey was planted next door to Britain’s only fast breeder nuclear reactor at Dounreay, which had liberally coated much of the beach and inshore water with radioactivity. This is now slowly being cleaned up, but it then prevented divers from getting back the remains. Either way, it cost insurers over £1 million and did nothing whatsoever for the cause of wave power. Entitled Ocean Swell Powered Renewable Energy, it turned out not nearly as successful as the fish-eating hawk it was named after.

Things have changed, but it is sometimes not difficult to think that there are just too many different types of wave power, with too many different champions. After all, that quick form of Google “People also ask,” has three rows on top of each other: “What are the three main types of wave power? What are the four main types of wave power? What are the two main types of wave power?” Equally, those involved cannot resist giving the machines suitable names to show their benign nature. The Oscillating Wave Surge Converter (OWSC) is known affectionately as an Oyster.

There is also the familiar round of material about the obvious power of the oceans. The US Energy Information Agency (EIA) has stated that the shores on the US coast have the capacity to produce 2.64 trillion kWh of electricity a year or roughly 64% of total US utility output in 2021. The International Renewable Energy Agency (IRENA) believes that around 2% of the world’s 800,000 km of shoreline could give about 30 kWh per metre. This is just under twice the US figure if it ran for 365 days a year. Equally, of course, oceans cover 71% of the earth and if all the ice melts, sea levels could rise by 2.7 kilometres. So we had better get on with it.

To give IRENA their due they do point out that “there is a lack of industrial cohesion” about the business. In addition, there are four rather distinct matters that have to be dealt with. First and foremost is the machine itself and whether it rolls, pitches or heaves. Then comes the tricky question of how it is tethered, whether on foundations or mooring, which was the Osprey problem. Then comes how the movement is turned into electricity at sea or on land and finally how do you control the wretched thing as the force ten gale comes hurtling down the coast. Unlike wind power you can’t just feather the blades and hope it does not fall over, nor can you just pull it out of the sea.

This may explain why nobody is thinking of water further than 6 km offshore or deeper than 50 metres. The problem here is that waves are not only unpredictable in size, but also produce energy in three basic directions. They heave into the shoreline and retreat. They pitch up and down and they also roll in a circular motion. How much they pitch, how much they heave and how much they roll ultimately depends on the beach and naturally enough on the tide, which powers the whole exercise, dictated by the moon. Actually calculating the combined effects of these three forces is beyond the dreams of Pythagoras. In the end a choice must be made as to which of the movements is the one to capture. Is it the sideways motion, the upward and downward motion, or is it the rolling movement? Trying to have all of them is tricky, to say the least.

The technological results so far are many and various. Attenuators looks like large bulbous snakes sitting on top of the sea with flexible bodies that bend and straighten according to the waves underneath. Point absorbers are effectively columns with floats on top. These floats go up and down the columns as the waves pull them up and let them down. Oscillating surge converters do a similar thing, although the waves drive them sideways and backwards rather than up or down. Overtopping devices let the waves flood into the floating reservoir barrier and turn a kind of turbine as they flow out again. Finally, oscillating water columns consist of a wall with a cover over it, which forces the waves into a column, which in turn pushes up air into an impulse turbine. This turns as the air is pushed into it and reverses as the air is forced out again by the falling water. These have the considerable advantages in the fact that they are actually on the shore.

Oddly enough, one of the most successful wave power companies Eco Wave Power uses a version of this latter system, using a wall structure on land along with a floater. This goes up and down with the waves, forcing compressed hydraulic fluid into a piston, which fills an accumulator from whence it pushes a hydraulic motor. This in turn runs a generator and the fluid returns to the pistons. Under their formidable CEO, Inna Bravermann, this Israeli-based company has been signing agreements for pilot plant around the world, most notably for the first 4 MW section of a 77 MW on grid-connected plant in Ordu, Turkey and others in Gibraltar and Los Angeles. Eco Wave put their potential projects at 325 MW of capacity and the price at $44 per MWh. And they can be forgiven for saying that potential global wave power capacity is 350 GW  because this is about 150 GW less than the IRENA estimate and thus more realistic.

All power to their elbow and at least they have a wave power system that actually works and is unlikely to be blown away in the next major storm. In this, the company differs significantly from the Portuguese company, Enersis, whose three Pelamis attenuator machines amounting to 2.25 MW were launched with a great fanfare 5 km off Porto in September 2008. They were returned to harbour two months later with technical problems. A second version did not survive the development process either.

Elsewhere, there was a wave swell machine, using an oscillating water column in the Bass Strait, which was bottom mounted and ran from January to June in 2021. Unhappily, while it worked fine, it had a capacity of only 200 kW. Rather larger is the Orbital 2 off Eday Island in the Orkneys, which is aiming at 2 MW. This is effectively a large propeller underneath a floating structure designed to catch the flow of tide water around the island at a cost of $12 million. Orkney is the location of the European Marine Energy Centre, which hosts the Integrated Tidal Project for connections to the European Grid.

Overall, back in 2020, IRENA put the amount of working wave power capacity at 2.31 MW. This, if functioning at, say, 100% of capacity would supply around 3,000 UK households, or 843,150 kWh a year. It is a bad habit of renewable energy technology PR to make similar statements always accompanied by a stream of exclamation marks: “This machine will provide enough electricity to power the entire population of Little Snodgrass in the Marsh, with enough electricity left over to keep the lights on by the crossroads all night!!!” In 2021, the world used 25,343 TWh or 25,343,000,000 kWh of electricity. In the context of this growing consumption, the current contribution of wave power machines is sweet f…all.

Well, by all means keep trying to find a machine that will truly rock, rattle and roll. But it might be sensible to concentrate on, say, one like Eco Wave’s idea. But really, if the sea is going to make much impact on mankind’s ever-increasing demand for electricity, we seem to have forgotten far easier ways of doing it.

Way back in the mists of time, or January 1961 to be precise, EdF placed a dam across the La Rance River, near St Malo in Brittany. Gradually over the years, they added 24 turbines and made a power station of 240 MW. At around 40% of capacity, it has been providing 0.012% of all French electricity ever since. Certainly, at the beginning there was considerable concern about the dam’s effect on the river, particularly during its construction due to silting. However, as time has gone on, its detectible effects now seem minimal.

Similarly, South Korea, desperate for increased land and fresh water near its capital Seoul, built a 43.8 km artificial lake by the sea in 1994. Known as Sihwa Lake, it was behind a 12 km sea wall. It was not a success. A lack of freshwater flowing in accompanied by industrial waste rapidly made the water undrinkable. The decision was made to scratch the freshwater idea and fit 10 turbines along that wall by 2011. The sluice gates are shut as the tide rises and then opened at high tide, when the seawater rushes in through the turbines, twice day. As the tide recedes it flows out, taking any industrial waste with it.

Environmental purists may not like this later point, but the fact remains that the station produces 550 GWh of carbon-free power annually to the South Korean grid, from a capacity of 254 MW. Admittedly at $248 million, this wasn’t a cheap exercise, but then the main idea was not to make a tidal power station in the first place and it is currently the world’s biggest. It is also a pretty good tourist attraction too.

If these two examples say anything, it is that harnessing the power of the sea is really a job for the big battalions. Sure, there are a lot of good engineering ideas out there and people highly dedicated, but they have to get away from the idea that 2 MW of capacity is an achievement towards today’s needs. Maybe in the context of the banking industry’s sudden and much advertised belief in environmental lending, they will get away from the idea that $15 million is a worthwhile punt to risk on the sea. Government backing is needed also. After all, we don’t just need 20-odd of Eco-Wave’s machines, but hundreds of thousands of much bigger ones.