Why wave power isn't everywhere (yet)

In 1974, a Scottish professor invented something that could have changed the story of energy. THIS contraption, called the Edinburgh Duck. Don't blame me, I didn't name it.

. . But if you squint really hard you can, sort of, see it.

. . *quack quack* Anyway, the duck's butt bobs up and down with WAVES to generate clean electricity.

It attracted a lot of attention from the UK government and press around the world. Because it had huge potential. Waves are everywhere, consistent and full of power.

But nothing came of it – just like the countless other sci-fi-looking wave energy devices invented in the following decades. Forty years later, we still get only a laughably small amount of energy from waves globally. But that might soon change.

"We're going to start seeing this technology out in the ocean in the next couple of years. " So what's happened to the duck, and all these technologies? And will wave power ever live up to its potential?

For at least 200 years people have tried to figure out how to harness the ocean's energy. Over a thousand patents have been filed. And they all pretty much look different.

Because unlike the wind industry, which has more or less converged on an optimal design, the horizontal-axis turbine, wave power is still in development. Because waves are complex. They don't just travel in one direction like the wind – so you can't just stick a turbine in somewhere.

Let's zoom out a bit to understand. Waves form when wind blows over the ocean. Friction between the moving air and the surface of the water causes ripples that eventually grow to form waves.

The size of waves depends largely on three things: the strength of the wind, and how long and far it blows, unobstructed, over a stretch of water. Which is why you find the biggest waves and the best surfing spots along the western coasts of north and south America, Europe, and parts of Africa and Australia. So with waves, it's not that each particle in the water travels from ocean to coast.

Instead, each one remains almost in the same place, moving in a circle as it gets energized by the wind. The energy is then transferred along to the next particle, and so on. They move with the most intensity at the surface – dwindling the deeper you go.

Which kind of explains the sheer diversity of devices that attempt to capture different kinds of movement: at the surface, near the seafloor and at the coast. So waves are complex, but we can still predict how they're going to flow. Satellite data on wind can help understand wave swells days in advance.

There are various basic designs, but here are a few main ones: A point-absorber: It floats at the surface and absorbs energy from all directions, while staying connected to the sea floor. The relative movement between the buoy and the stationary part moves a piston inside into an energy conversion system – that drives a generator. A surface attenuator: which is made of multiple floating segments, connected together and placed perpendicular to incoming waves.

The relative motion between each segment once again powers an energy conversion system. And third, the oscillating water column: a partially submerged, hollow structure. As waves enter it, they compress and decompress the air column, and push it through a turbine, which connects to a generator.

The duck belongs to a category called the terminator, similar to the surface attenuator. There are also devices that are attached to the seafloor, whose up and down or sideways flapping movement generate electricity through the relative motion. And still others that are installed closer to the coast where waves crash.

Some of these concepts have existed for centuries. They all work. But it's their performance in real-world conditions over the long-term where the big question mark lies.

"It's an extremely hostile and complex environment to place anything in the ocean. And to generate consistently, reliably, and over a very long period of time, to generate power from that environment, is really challenging. " Matthew Hannon researches technology innovation and has dived deep into the history of wave power.

By "hostile" he means that salt water is so corrosive it eats up most metals over time. And marine creatures begin to use it as a base to live on, slowly breaking it down. Corrosion-resistant alloys, like steel, are available but they're inherently costly.

Underwater devices also need maintenance, which means divers, boats and platforms. So even at the testing stage, the investment that wave power needs is incredibly high. But cost is not the only problem!

Another major one is competition. The Edinburgh duck was supposed to be a solution to the energy shortage following the oil crisis in 1973. But by the time it was ready for testing, the nuclear industry was receiving so much more attention that the duck lost the race.

"From the late 1980s into the late 1990s, it was very quiet, very little funding available and then its renaissance from the advent of the millennium basically onwards. " This time, two companies tested wave energy devices off the coasts of Portugal and the UK. The first was an attenuator.

Inspired by the duck, but with a much more complex design and set up completely offshore. The other was a submerged flap, also offshore. Both had more reliability issues and required more maintenance than their manufacturers expected.

And so after months of testing, investors lost interest. They had to shut up shop. And like in the first instance with nuclear, this time, wave power was pushed to the fringes by onshore renewables like wind and solar – whose prices had fallen by up to three and 10 times respectively in the 2010s.

But similar to the 1970s, we're facing another energy crisis today. The need to get to net-zero emissions. Even as the demand for energy is rising.

Estimates predict an average 30% rise in demand by 2045. And here's where wave power comes back into the game. On a dark gloomy winter's day, where the sun isn't shining and the wind isn't blowing, alternatives – including tidal and especially wave power – have a big role to play.

Not only are waves predictable, they're reliable. Waves flow almost consistently all year round. Wave energy devices can also generate several times more power for the space they occupy, compared to wind turbines.

Simply because they are smaller, and water is hundreds of times more dense than air. Environmentally speaking, some machines could disturb the seafloor habitat and create noise, and this needs to be considered. But early indications are that the impact is relatively low.

Since most devices float along with the current anyway, they're unlikely to hit marine mammals. "So the story continues at this point. " Several devices are now back in the water.

In Australia, a few companies are seeing success. One array of submerged buoys even connected a device to a local grid. The US Navy recently invested $6 million into testing devices off the Hawaiian coast.

And a Japanese professor and his team are trying out a new operating principle – this time putting small turbines close to the coast. In 2021, Europe installed three times more capacity in wave power than the previous year. Both public and private investments rose significantly, totalling 70 million euros in both tidal and wave power.

While in theory the potential for waves is three times today's global demand, it's estimated that by 2050 wave power will generate 10% of global power, which is a significant share. The biggest testing facility at the moment, that is arguably showing the most potential, is in Scotland. The perfect location, with its strong winds, large swells and history of testing wave devices.

The Scottish government has even created a system of supporting companies to learn from the mistakes of others. One company testing at the moment is Mocean energy. They simplified their devices, and looked to attach them to existing infrastructure for easier maintenance.

They also looked for niche markets. "And kind of, ironically, where we ended up was in oil and gas. " It sounds like an oxymoron, but you heard that right.

Oil and gas companies have the money, the infrastructure and the need for energy where waves can produce it. "It was a good economic opportunity. So we always saw this oil and gas as a good high value market, but it's also a stepping stone to other markets.

" Industry analysts say wave power is behind wind by around 20 years – and it won't catch up with or replace either wind or solar anytime soon. But right now, it's alternative markets like offshore oil rigs – and less problematic ones – that do look promising. Like islands!

There are around 2,000 islands with less than 100,000 inhabitants that lack grid connection. And use diesel generators for energy. As we head towards a zero-carbon world, wave power could be the perfect resource here, and several companies are looking at various islands already.

Others want to attach devices to platforms in the aquaculture industry. "In the longer term, where we see wave energy fitting in, in terms of the total impact it can have, is being combined with offshore wind. " Sinn Power in Germany is one company working to attach wave power devices to offshore wind platforms that also have solar panels.

And the infrastructure for grid connection. Eco Wave Power in Israel has attached them to breakwaters and piers that feel the effect of the most aggressive ocean waves. At the moment, neither the capacity of installed wave power nor the cost of the energy it can produce compares to other renewables.

But its value lies in the diversity it can bring to the mix. To make wave power viable, the industry needs to follow a path similar to other renewables – with support and investment plus time to test. As more devices test and produce power, economies of scale will bring down costs like they did for wind power.

And waves can fill a gap that other renewables cannot. Do you think wave power's time has finally come? Let us know in the comments below.

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