Wave energy is in the spotlight worldwide partly due to China’s brand new, megawatt-scale, wave energy device. This device isn’t the first of its kind, but its sheer size represents a breakthrough for this underutilized but potent branch of the clean energy family tree. What is wave energy generation, and how does it compare to other renewables? And if wave energy is so great, then why is it lagging behind solar, wind and others?

This is a massive WEC (wave energy convertor) called the Nankun mobile power bank. The Nankun weighs in at 6,000 metric tons, and can generate up to 24,000 kilowatt-hours of electricity per day! This is equal to the daily electricity consumption of 3,500 households. The sheer size and megawatt-scale generation of the Nankun represents a big leap forward over older, smaller kilowatt-scale wave energy devices.

But Nankun isn’t the only WEC. From serpentine point absorbers buoys to Oscillating Water Columns that use waves to move air to move turbines, there’s a vast array of different designs all competing to be the one to commercially crack wave energy. Why is this? It’s not like we see a ton of different ways to turn the wind into energy, and there’s not a huge variety of different solar panel shapes. What makes wave energy so weird?

Wave power faces more engineering challenges than other renewable energy generators. WECs have to be strong enough to get tossed around by the wind and water all day, every day, for decades, with as low a maintenance as possible. These systems have to be designed to withstand rough seas, and various storms and hurricanes as well. A poorly designed system will be slammed to pieces by waves.

The ocean itself is not particularly welcoming to our technology. Salt water is corrosive and can destroy metal and electronics. While waterproof casings and sacrificial anodes can help protect some structures, salt spray is still one of the major torture tests on marine electronics. But despite these challenges, the clean energy potentially offered up by the seas is too good to pass up. And with the field as young as it is, there’s just a plethora of weird and wonderful devices all vying to efficiently overcome these challenges and become the industry standard. 

Wave energy is a branch of the hydropower family tree. Instead of using dams and gravity to capture the potential energy of water as it falls, it’s translating the motion of the ocean into nearly limitless energy. We have already created an extensive and impressive network of wind farms: today there are more than 1,500 operational onshore wind farms across Great Britain, generating over 12 gigawatt hours (GWh) of electricity for the national electric system. First, unlike wind, oceanic waves are not intermittent. And second, water has more mass than air. Because potential energy is calculated using mass and velocity, it has potential to transfer more energy. That means there’s a lot more potential energy in the sea available for capture. In theory, the U.S. coasts alone could generate up to 2.64 trillion kilowatt hours of energy. That’s roughly 64% of total U.S. utility-scale electricity generation in 2021. And waves tend to increase in the winter. So, when shorter days start to negatively affect solar energy, wave energy only gets stronger!  This is a major opportunity for reaching net zero.

According to Robert Thresher of the National Renewable Energy Laboratory (NREL), even though there are a vast array of different designs, it’s possible that we have yet to invent the best WEC. Back in 2014 some experts estimated wave power to be about 30 years behind wind and solar. However, since then the number of papers published on wave energy has nearly doubled. Even though research is growing rapidly, why don't we ever see it in the news? 

But again, these challenges are worth addressing, due to wave energy’s crazy potential. University of California at Berkeley’s Reza Alam put it like this: Every square meter of a solar panel receives 0.2 to 0.3 kilowatts of solar energy, and every square meter of a wind tower absorbs 2 to 3 kilowatts. Every meter of the California coast receives 30 kilowatts of wave energy. Certainly puts the potential of wave energy into perspective. And there’s no reason we can't do the same here in the UK. Solar is currently one of the cheapest ways to generate power, and wind energy is our most developed renewable energy source, but soon we may be able to use wave energy as a vital tool against climate change.