How Carnegie Clean Energy uses data to capture the power of the ocean
The ocean covers 71 percent of the earth's surface, and most of that water is absolutely teeming with energy. The U.S. Energy Information Administration (EIA) has calculated that the annual energy potential generated by the waves hitting the U.S. coastline alone equals as much as 2.64 trillion kilowatt-hours, roughly two-thirds of the country's energy consumption in a year.
To date, this potential has gone virtually untapped, despite decades of work to commercialize ocean-based energy. (The first patent for harnessing wave energy dates back to 1799.) The amount of power being generated by marine projects today is so small that the EIA doesn't even break it out as a source. For example, after nearly 20 years in development, Verdant Power's Roosevelt Island Tidal Energy (RITE) Project was finally fired up in 2020 in New York's East River, where it is using the tides to generate electricity. The 1-megawatt project produced 275 megawatt-hours in the eight months ended June 2021, making it the largest marine power generator in operation in the U.S., though it produces enough juice to power only 387 average American homes.
Other parts of the world are further along, but even in Europe and Asia, reaching a point where marine-generated energy makes a meaningful impact on power generation seems decades away. Worldwide, an estimated 527 megawatts of ocean-based power capacity was online by the end of 2020. (For comparison, solar production capacity hit 760 gigawatts last year, more than 1,400 times higher.)
So what's the holdup?
Ocean-based hydropower can be generated primarily in four ways. Solar energy captured by oceans can be tapped to release thermal energy, tides and currents can drive power generation as the sea level rises and falls, and salinity gradients can release energy when freshwater and saltwater mix. But a large chunk of scientific interest today is focused on wave energy, a source of power that is highly visible and easily intuited by anyone who's observed a wall of water crashing into the shore.
The catch? It's just not that easy. In fact, at present, there are no wave power generators currently operating anywhere in the U.S. Arguably the biggest obstacle is that wave power is playing catchup against a host of other, much more mature renewable energy sources that are currently far cheaper.
"At the end of the day, electrons are all the same, no matter where they come from," says Jonathan Fiévez, CEO of Carnegie Clean Energy, an Australia-based wave power technology company. "The people that buy electrons are usually accountants, and cost is absolutely the biggest factor. New energy technologies cost a lot to develop, and that can be very tough in a commodity market."
The cost of solar production and wind power today are both typically quoted as running 4 to 6 cents per kilowatt-hour. Of course, these technologies didn't get there overnight. Discussing offshore wind farms, Fiévez notes that back in the 1990s, "everyone was saying that it's too expensive, that it's never going to be competitive. Fortunately, Europe had the vision to put money into this. They poured billions into loss-making projects for years." That vision panned out: Fiévez says that by 2018, European offshore wind had already surpassed the goals set for it to reach by 2020.
One big issue that drives up the cost of ocean-borne power is efficiency—or rather, the lack thereof. To date, most marine power generation systems have been notoriously inefficient, capturing as little as 3 percent of the available power from a wave, according to Tom Denniss, executive chair of Wave Swell Energy, also based in Australia. More advanced systems are improving on that, but there's clearly a long way to go.
Getting the oceans to cooperate
Another big challenge is the environment: The ocean is an inhospitable place to try to make electricity, and building equipment that can survive the constant onslaught of the sea has proved difficult. Surprisingly, big waves are problematic, not beneficial. Small, regular waves, says Denniss, are known in the industry as "money waves." He adds, "In deep water, you can get hit with waves up to 100 feet high. Trying to construct a device that can survive those waves is unbelievably difficult."
Several noteworthy experiments, like the Wello Penguin and the Oceanlinx generator, have been wrecked by environmental exposure, a problem largely unheard of on land. "Many wave energy developers were so occupied with cost and survivability difficulties that they did not even have the chance to properly connect their technologies to the electric grid," says Inna Braverman, co-founder of Israel-based Eco Wave Power. Compounding this issue, she says that many insurance companies have balked at underwriting these installations.
And don't forget that any device in deep water will require people qualified to maintain it. "Some of these devices have been placed 10 miles offshore and 100 feet below the surface," says Denniss, "which means a servicing ship must have a decompression chamber available for divers—who have to be trained engineers—just to change a bolt or nut. It can become prohibitively expensive." There are also potentially significant but largely unknown environmental risks to marine habitats and ocean wildlife from marine power, including the hazards created by spinning turbines, underwater cables, underwater noise, electromagnetic fields, and more.
Deploying closer to the shore is an option, but coastline aesthetics are yet another issue, and to date, few ocean-bound power generators have been designed with looks in mind. In 2004, the Pelamis Wave Power energy converter was the first offshore device to successfully deliver wave-generated energy to the electrical grid, quickly becoming the public face for the industry. It was a series of garish red-and-yellow tubes, 3.5 meters in diameter and 120 meters long in total, floating on the surface. (The company behind Pelamis eventually went bankrupt, and its devices were scrapped.)
Wave Swell's UniWave200 is difficult to describe, but it's something like a cross between a homemade submarine and a World War II bunker—a mass of metal and concrete standing 46 feet tall. Even Denniss acknowledges that the machine, which is described as an "artificial blowhole," would not be welcome on the shores of the Riviera.
Why the ocean still makes sense
Despite all of the negatives and caveats, the potential of ocean-driven power is real, and headway is being made against its challenges. Wave Swell's 200-kilowatt project in remote King Island, Tasmania, began producing power and sending it to the local grid in June 2021. Denniss says that the cost competitiveness of the technology with other renewables and fossil fuel generation will be a function of how quickly it is adopted. "It's likely to already be competitive with diesel generation in some remote sites," he says, which is the most common form of power generation in remote and island locations—and a very expensive one. Naturally, wave power isn't just cheaper; it is also immensely more environmentally friendly.
Today, the company is looking for a larger partner that can roll out UniWave products on a much bigger scale, which would help bring costs down considerably. "The more you install," Denniss says, "the cheaper it becomes."
And while the UniWave may not be designed for beachfront life, Denniss notes that UniWave devices can also do double duty as a breakwater, so sea-ravaged regions don't have to build jetties and seawalls.
In contrast, Carnegie's CETO technology, which is completely submerged and invisible from the shore, bobs only a few feet below sea level, making it easier to service than deep-water technologies.
Another big advantage of wave power is predictability. "The sun stops shining and wind stops blowing, but ocean waves never cease," notes Fiévez. He says that wave forecasts can usually look a week into the future, and when coupled with CETO's numerical models, they can determine within a 20 percent margin of error what energy production will be. "That's unheard of in solar or wind—and in a grid that's becoming more and more variable because of wind and solar use, having a renewable supply that's consistent and predictable is really valuable."
Wave prediction is even possible on a wave-by-wave basis. This capability has been developed by Carnegie using neural networks trained on a Cray XC40 supercomputer. CETO can even generate precise knowledge about the shape and timing of upcoming waves, which helps it extract the maximum amount of energy from each one that passes by. The controller delivering this performance comes in part courtesy of Hewlett Packard Enterprise, which loaned AI and programming talent to Carnegie to develop the necessary algorithms for the project. The technology involved is built using reinforcement learning techniques, a subset of AI that improves its models by using the feedback created by its own activities and the environment in which it operates.
While, for now, marine energy may be most applicable in very remote and hostile locations—where energy costs are high, the electrical grid is underdeveloped, and power needs are comparably limited—innovators are hopeful for a future in which wave power is seen as just another tool in the renewable energy arsenal for any region with access to the ocean.
"I think there's a really good opportunity for wave energy," says Fiévez. "It's a hard task, but we're going to crack it."
"The more you install, the cheaper it becomes."
This article/content was written by the individual writer identified and does not necessarily reflect the view of Hewlett Packard Enterprise Company.