You may have never thought about such a question, nature provides us with light energy, so it forms a photovoltaic solar power generation industry, provides wind energy, so it forms a wind power industry, but nature provides us with more powerful water energy - ocean waves, why does it not form a similar hydropower generation industry?
You might say, yes, we have hydropower, but hydroelectric power is essentially using gravitational potential energy to generate electricity, not using water fluctuations to generate electricity, like using light fluctuations, air fluctuations, and water fluctuations are obviously much more powerful than light fluctuations, air fluctuations, which means that we can use equipment that is much smaller than wind and solar energy, and we can get the same amount of electricity, why haven't we heard of such power stations?
This may be coming to an end, as a Finnish start-up has invented this magical "wave energy" power generation, which is seven times the size of wind energy, and a small installation can provide electricity for hundreds of homes.
The company, AW-Energy, was founded by Rauno Koivusaari, a diver who was diving off the coast of Finland in 1993 when he spotted a wreck with a huge hatch that bobbed strongly in the waves.
In 2019, the first 350 kW commercial wave turbine was put into operation off the coast of Portugal and successfully connected to the grid, with a 1,000 kW generator estimated at 624-813 MWh.
The wave wheel is placed on a rectangular platform and is constructed of a generator and a huge force take-off plate (PTO). The force take-off plate is equivalent to the blades of a wind turbine, although it looks very large, but it is much smaller than the blades, the force take-off plate is fixed on the platform, it can swing back and forth under the action of the waves, and the hydraulic oil pump is driven by the hydraulic rod to generate electricity, and a PTO can absorb about 1500 kilowatts to 2000 kilowatts of surge power.
The installation of the wave wheel is also very simple, the entire platform is towed by the tugboat to the offshore position, and then sunk to the seabed at a depth of 8-20 meters and anchored, because the depth of 8 to 20 meters is where the waves are most powerful. Due to the ebb and flow of the tide, the PTO may be completely submerged or partially exposed to the water, providing a capacity factor of 25% to 50%, which is about the ratio of actual output to rated capacity, depending on the wave conditions.
Wave turbines can be deployed individually or together to form a power farm, with a wave farm generating approximately seven times the nominal capacity of a wind farm in an area of the same size. In addition, the wave energy generator is basically below the water surface, avoiding the visual impact of the giant wind turbine on the natural landscape. Then there is the hydraulic, mechanical and electrical systems that are completely sealed, protecting marine life from noise and other possible contaminants.
Crucially, compared to solar energy, which only has a few hours a day and wind energy that doesn't know when it blows, wave power is basically all-weather, with an average of 30-40% less intermittency, which means it can generate more electricity while taking up less space. Moreover, it can also be combined with offshore wind farms to make more efficient use of the energy that nature has given us.
It seems that wave energy power generation seems to be really perfect, far more than wind and solar energy, and you may have a huge question in your heart, since it is so good, why has no one developed it before, and there has not been a wave energy industry like wind and solar energy? Is it too costly?
AW-Energy claims that their levelized energy costs are $100-$150/MWh, lower than the $82-$255/MWh for offshore wind, and they are ambitious that this could be a real game-changer.
It seems that cost is not an issue, but will it really change the rules of the game in the future and catch up in the clean energy market? I think this idea may be too optimistic, because there is one of the most critical questions that has not been solved, how long can a generator last?
Due to the fact that seawater contains a variety of salts, the wave energy device will inevitably be corroded and eroded, and when the company scooped up the first machine for maintenance in 2021, it was found that it was rusty and covered with barnacles. Whether it can become the third type of clean energy used by human beings on a large scale may still have a long way to go.