Wave power is something that I don't really think about all that much when I consider clean alternative power sources. Normally my thoughts drift straight to solar and wind and then on to the dreamy hunk that is fusion. But that may be off base. Here's a presentation by Max Carcas of Ocean Power Delivery at a Google Tech Talk.
The presentation is about an hour long but it gives great details about the actual device as well as energy potential, market and economics of wave power. Watch the video if you have the time he's much better at explaining it than I am, but I'll put some of my notes below. Skip to about 26:00 for video of the wave tank simulation.
Solar currently generates 100 watts per square meter, wind 1000 watts per square meter while wave power houses the potential for 20,000- 70,000 watts per square meter depending on teh region. Wave energy can be thought of as compressed stored wind energy.
Waves are a highly
forecastable energy source, which is a major concern with wind and solar generation. Output, even without forecasting, can be held constant within a 5 and 10% threshold.
The device is called "
Pelamis" (a type of sea snake) for its vertical and horizontal motion as waves pass under it. It resides in an optimal depth of 80m which is 2-10km from shore depending on the region. At this depth the waves are not compressed by the shore and retain more energy while remaining in a non-volatile state (not breaking).
A single unit is 140m long and 3.5m wide with 4 rigid sections and 3 joints that contain pneumatic actuators. The joints move up and down as well as side to side at non uniform angles to induce a kind of harmonic tuning that is used to maximize the power output depending on the type of wave. That single unit will average around 750 KW output which is enough for about 500 homes.
The device is designed to be survivable with "load shedding" as an innate feature of the design. If a large wave is encountered it will simply pass through the wave rather than rising too high on a crest and breaking apart. This is much the same as the way that wind turbines can feather in excess wind or a hydro-electric plant can discharge excess water.
The technology was designed using existing technology as a guide. Natural gas, Oil and various other marine industries have developed standards couplings and materials that are well suited to this type of environment. The device itself employs very few revolutionary, and untested, modules which makes it very reliable.
The current cost of deployment per kwh is above wind but below solar. There is a distinct trend in applications of new technologies that cost drops fairly dramatically as process is streamlined and technologies refined. Wind turbine prices have dropped 80% since the first wind turbine project; so one might make an educated guess that a similar trend will follow for wave power. Government subsidies generally provide incentive to new projects during the first few years to help with this innovation cost hurdle, as we've done for solar and wind.
Remember the first time you saw a child tethered to a parent with bungee cord? If you're like me, you immediately thought "child on a leash, the next step will be choke collars." Well that may not have happened yet, but I still think those kids are getting treated like pets and are more likely to behave as such.
