Having had some experience with the ocean, wave energy has always seemed to me to be on the fringe of reality. Especially devices mounted on the surface.
The ocean has the power to destroy anything made by man.
One ship I was on hit a rogue wave, and pounded heavily. While damage was not immediately apparent, it was discovered when the ship went into dry dock.
The wave had buckled the 3/4-inch steel plates on the ship’s bottom inward, by about 4 inches between several frames for much of the width of the ship.
Some may remember pictures of the cruiser Pittsburgh, where 100 feet of its bow section had been shorn from the ship by waves.
These forces will inevitably destroy devices on the surface trying to capture the motions of waves to produce electricity.
There have been several attempts to manufacture devices of this sort. Most have failed.
Here’s a list of a few companies that have had problems with wave development.
- Voith Hydro decided to shutter its Wavegen operations in Scotland in 2013
- Irish wave energy converter maker Wavebob shut down
- Oceanlinx, a wave energy developer, went into liquidation in 2014
- Ocean Power Technologies, who make PowerBuoys, canceled an Australian project
- Aquamarine announced plans to lay off a “significant” number of staff
There have been two successful tidal wave projects: One, in France in 1966, the second, in South Korea in 2011. These are rated 240 MW and 254 MW respectively.
Bulb hydro turbines were used in these installations, and have also been proposed for use in some other tidal installations as depicted in this artist rendering, courtesy Swansea Bay tidal lagoon.
But the wave sector is having serious problems.
Of 40 projects announced between 2006 and 2013, they are all still in the demonstration phase.
It would appear as though a few tidal projects have some reasonable chance of becoming operational, though the cost of electricity produced by these installations is expected to be very high.
Andritz Hydro has an order for three 1.5-MW tidal current turbines for a planned tidal array at Pentland Firth in Scotland. These units have the shape of wind turbines, and being located beneath the surface, may not be subject to the extreme destructive forces of the ocean.
The International Renewable Energy Agency (IRENA) noted, “Levelized costs of ocean energy technologies are currently substantially higher than those of other renewable energy technologies.”
There is no question that the ocean has tremendous power and virtually unlimited energy, but trying to capture that energy to generate electricity is unlikely to be accomplished economically on a wide scale with any existing technology.
There are few environments on earth that are as harsh as that found in the ocean.
The allure of wave energy is understandable, but the reality is that we won’t be seeing widespread generation of electricity from the motion of waves or tides.
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