ON A NEW APPROACH TO WAVE POWER

FROM THE DEEP

For a long time now, the one alternative energy source that has most captured my imagination has been wave power, for a variety of reasons.  This article in CNET, titled "Riding the power of undersea waves",  captures some of them in this excerpt:

"Wave power, at least according to its advocates, could become a staple in renewable energy over the next two decades. Waves are far more predictable than wind and solar conditions. Satellites can track wave trains out at sea and give utilities and power providers advance estimates of how much power they can hope to generate from the sea. Water is 800 times denser than air; thus, a few devices planted in a relatively small area can generate as much power as a large wind farm."

However, the piece goes on to add:

"But there is the catch. Wave power devices have to sit in some of the harshest environments on the planet and function fairly flawlessly to be economical. Right now, virtually all wave power systems are prototypes."

The piece then focuses on a company called WaveRoller trying a different approach to wave power than many of it's peers:

"The company, based in Espoo, Finland, says it has devised a way to generate electricity from waves without buoys or other floating devices, the mainstay of other wave power companies.

Instead, the company wants to plant oscillating fiberglass/steel plates on the sea bed. Waves rolling in push over the plates, which rebound after the wave passes to only be knocked down by another wave. The back-and-forth motion of the plates drives a piston and creates hydraulic pressure. The pressure ultimately gets fed to a turbine to generate electricity.

By being completely submerged, WaveRoller's device could help quell some of the NIMBY-ism that comes with building in coastal areas..."

The number of this approach shake out as follows for now:

"The plate in the latest prototype measures 4x4 meters and can generate 10 kilowatts to 13 kilowatts of power. Commercial units will likely consist of three plates lined up near each other and produce around 45 kilowatts, he said. Thus, you'd need about 22 three-plate devices for a megawatt. A single WaveBob can produce more than a megawatt of power."

It's a long time ago before these systems are commercial contributors to the energy problem, with the earliest estimates in the 2010 to 2015 range.  But it's fascinating to watch the rapid changes in the underlying technologies while we wait.

Comments

[a]

Looking that the flash demo I have these comments.

1. The device is still in harsh conditions, just like surface devices.
2. being underwater they will be harder to maintain.
3. How will the marine fouling problem be dealt with - especially as the piston is exposed.
4. The device only works in shallow water. This is a major problem as surface devices can be situated anywhere on the oceans.
5. because they are shallow water devices, they will be situated in rich ecosystems - this affects both the local ecosystem, plus other uses, e.g. fishing.

It's an interesting idea, but I doubt it can be more than a niche product.