It’s been estimated that ocean waves near coastlines produce more than two terawatts of power globally. Nearly half of the world’s people live near the ocean, so it makes sense to harness that wave power and convert it to electricity. So why isn’t that being done?

Unlike wind power, where the three-blade horizontal axis wind turbine (HAWT) is clearly the most efficient and cost-effective model, nobody has yet developed a wave power system that can generate electricity at a reasonable price. While some would argue that it will never be done, the same was once said about powered aircraft, photovoltaics, and many other technologies that we currently enjoy. So as long as a device doesn’t violate the laws of physics, I’m not willing to say “never” when it comes to wave energy. Fortunately, many engineers and entrepreneurs feel the same way, resulting in a surge of wave power devices.

Among these new wave harnessing machines is the bioWave, an inverted pendulum that sways back and forth with the waves, mimicking the motion of seaweed:

Capturing Wave Power

The bioWave stands 26 meters tall. Its large buoyant tanks (the “blades”) at the top capture the wave motion, which is then fed to a generator. In stormy conditions, the control system allows the tanks to fill with water, causing them to sink and lie flat on the ocean floor, preventing potential storm damage. When fair weather resumes, compressed air forces the water out of the blades - just like a submarine’s ballast system - and the bioWave returns to normal operation. On-board sensors detect the wave swell, so the “survival mode” operation is fully automated.

Converting to Electricity

Since wave frequency varies over time, frequency regulation is needed to ensure that the electricity that reaches the grid exactly matches the grid frequency. To accomplish this, the bioWave incorporates a self-contained O-Drive, which uses the back and forth linear motion of the blades to pressurize a bank of hydraulic fluid accumulators. The self-regulating hydraulic motor feeds a 250 kW electric generator, which produces grid-quality power. The O-Drive is detachable, making it easy to disconnect and bring to the surface for routine maintenance.  

Something Old, Something New

Although the bioWave is a new way to harness wave power, it relies on tried and true technology. As mentioned before, the storm survival system uses submarine technology. The automated systems are taken from robotic and industrial machinery, and many of its materials were originally developed for the aerospace industry.

Deployment

BioPower has spent nearly a decade researching wave power and testing various small-scale designs, leading up to the first 250 kW demonstration bioWave that’s being installed off the coast of southern Australia. It should be operational beginning in November of 2015. After at least a year of testing, engineers will examine the results and modify the design so it can be scaled up to a commercially viable 1 MW unit.

Here’s BioPower’s promotional video with more information:

According to the US Energy Information Administration, the world’s consumption of electricity is nearly 22000 TWh per year. That’s an average of 2.5 TW of power at any given instant. Given that there’s more than 2 TW of coastal wave power across the globe, harnessing even a fraction of what’s available could produce a significant amount of clean electricity. And that’s why people keep trying.