[Update] This interview was conducted in August in 2018. On Nov. 1, 2018, we learned Tesla delivered first Powerpack project at tidal power station, which echos the theory in this interview. We will further investigate this topic with follow-on interviews.
Earlier this year in June, Wales shelved a plan to build the world’s first tidal lagoon to harness offshore ocean power due to prohibitive costs. The decision was controversial in steel and coal-dependent Wales. I looked into the technical feasibility in this project and spoke to Maiyue Cheng, co-founder of an energy startup called Blue Ocean Energy Inc and a former Senior Fellow and ex-Managing Director at Rocky Mountain Institute (RMI).
Below is Maiyue Cheng’s comment:
“With limited previous exposure to the project in question, I can see a few fatal flaws in this project. Overall, tidal power is not the best representation of ocean wave energy for several reasons:
1) It depends highly on nearshore geology and seashores are often precious properties. It creates a high barrier to entry and is therefore hard to scale.
2) It seems to bear significant costs in civil works. These costs are not likely to fall in the foreseeable future, hence this doesn’t support the argument that these projects enhance the economy.
3) Any construction on the seashore will inevitably alter the ecology. After the initial novelty period, people may find this project distasteful, just as with onshore wind projects or large hydropower plants like the Three Gorges Dam. Its “green” nature is still debatable.
4) It is still reliant upon low-capacity factors (utilization hours against 8760 (365 x 24) hours each year), so its value to the grid is still fundamentally constrained.
However, I am sympathetic to the fact that wave energy is not getting sufficient attention from the “White Hall” or the “Great Halls of People” among leading energy-consuming nations. The ocean surrounding us offers a vast source of energy. In my opinion, the most prosperous kind of wave energy is the wave power generated a bit further offshore, preferably with a water depth greater than 50 meters. In these conditions, floating devices can be deployed to capture kinetic energy from the vertical movements of ocean waves, for which we have developed a breakthrough design to test its viability.
Why floating devices? Because they don’t require any fixed installation, which offers huge cost savings, to begin with. The floating devices never stop working as long as the ocean produces waves. They boast 72-hour advanced knowledge of a wave’s available capacity, thus becoming a source of “dispatchable power,” correcting the intermittence of almost all mainstream renewable energy (RE) sources such as solar and wind. Finally, similar to wind turbines, our inshore devices’ mechanical structure has the potential to scale economically by going below US$60/MW. It would make an ideal source of power for islands with a current unit size below 100KW. Once it’s further developed to the MW level, it will be a significant contributor to the main grid and offer an economical alternative to places like Hawaii and Fukushima, which have announced plans to turn their power supplies 100% green.”