Energy Generation from Ocean Waves

Here in Guadeloupe, my friends and I are surfing a lot. I love the feeling you get while catching a wave and floating on the water over the ocean. For me, this is what freedom feels like. However, I wondered why waves that are so powerful to move the human body, aren´t commonly used for energy supply yet. Why don´t we harness energy out of waves? How could energy generation from ocean waves work?

Potential and advantage of ocean waves as an energy source

Pecher and Kofoed indicate in the Handbook of Ocean Wave Energy that “the total wave energy resource exceeds by far the global consumption of electricity” (Pecher and Koefoed, 2017). Therefore, we deal which a highly valuable resource that could change the energy market when exploited efficiently. Ocean wave energy could create a new sustainable energy source, contributing to a transition away from fossil fuels. It advantages non-land consuming offshore energy harnessing and could make countries more self-sufficient. ¹ But is it technically feasible?

Technical feasibility of ocean wave energy

So far, there have been difficulties to access energy out of waves. It remains difficult to determine the environmental conditions at a specific location. There are a lot of parameters you have to consider while planning a WEC (wave energy converting technology), such as temperature, density, salinity, or ocean depth. ¹ When you wonder how temperature and salinity influence the ocean, you can read my article about Ocean Currents. Additionally, the corrosivity of seawater reduces the lifetime of these machines drastically. ²

Turbines are the most efficient way we have been aware of so far to convert mechanical energy (the movement of the wave) into electrical one. This is the principle behind wind energy and hydropower. In both cases the medium, the wind or the water, makes its way through the turbine, inducing a movement. Ocean waves are a little more complicated. Only a small fraction of this medium oscillates. This vertical movement is not able to spin a turbine. So how can we access this energy? ³

Technical attempts to harvest energy out of ocean waves

Despite initial technical troubles, blue energy out of waves is advancing. A huge number of technologies have been developed in the last decades to capture energy out of ocean waves. ¹

For instance, the wave roller tested close to Portugal. Close to the shore, the waves are swinging back and forth. The wave roller deploys energy exactly from this swing spot by moving back and forth with the waves. ²

The Company Eco Wave uses a different approach to capture wave energy. In a project realized in Israel since 2014, the device is attached directly to existing piers, where the water breaks. The movement of the wave creates pressure, which turns a hydro motor. This hydro motor turns the generator, closing the gap between wave energy and electrical one. ²

I will link the video below in which I found the information about the wave roller and the Eco Wave technology. I highly recommend this video because the images lead to better comprehension if you are interested in the technical details. Further, I find the story about the founder of Eco Wave quite inspiring.  

But there are way more technologies in development to capture the energy of ocean waves. The company “Uni Wave 200” just finished a 12 months pilot project near Kings Island, Australia (October 2022). The CEO claims the machine manages to capture half of the energy of the passing waves. ⁴

Conclusion

In this blog post you´ve learned different approches energy generation from ocean waves. Companies develop many different technologies to capture blue energy out of waves. This energy could be a supplement to other renewable energy on the market. In October 2022, none of these technologies outruns the others on the market. Let´s see what the future holds.

References:

1. Pecher, A., Kofoed, J.P., 2017. Handbook of Ocean Wave Energy. Aalborg: Springer Open.
2. Bloomberg Quicktake: Originals. 2021. Wave Power Could Be Energy’s Next Big Leap. Youtube. Available at: https://www.youtube.com/watch?v=jahAum3zLsY [10.10.2022].
3. MinuteEarth, 2019. Why Can’t We Get Power From Waves? Youtube. Available at: https://www.youtube.com/watch?v=PMRiKmgxrh0&t=108s [24.10.2022].
4. The Guardian. 2022. Wave energy machines on Australian south coast would slash renewable energy costs, CSIRO says. Available at: https://www.theguardian.com/environment/2022/oct/05/wave-energy-machines-on-australian-south-coast-would-slash-renewable-energy-costs-csiro-says [10.10.2022].