It’s been a while since we checked into the US Navy wave energy test site in Hawaii, but our friends over at Columbia Power Technologies steered us in that direction to check out their new StingRAY wave energy converter. The device, which is slated for utility-scale wave energy generation, will get its first full open-water demo at the facility. The US Navy has funded the project through its Naval Facilities and Engineering Command to the tune of $3 million.
Those of you familiar with wave energy (and its sister, tidal energy) know that this emerging alternative energy field is fraught with challenges, especially when you’re talking about utility-scale development. While the kinks are being worked out you’re going to see a lot of variation in design, so let’s take a look and see how Columbia Power’s StingRAY works that out.
Basically, wave energy converters rely on the natural movement of waves to drive a piston up and down, move a drive shaft, or stir up some other form of mechanical motion. The mechanical energy gets converted to electricity by a generator and there you have it.
That sounds simple enough, but aside from Scotland, which seems to have taken the ball and run with it, the global wave energy field hasn’t been keeping up with other forms of alternative energy, most notably wind and solar.
That could be about to change. The wave energy field seems to be taking some lessons learned from wind energy, as demonstrated by the StingRAY wave energy converter. The heart of the converter is a direct-drive system that eliminates excess moving parts, along with permanent magnet generators.
The StingRAY is built from corrosion-resistant composite materials, and it is designed with modularity in mind to reduce the cost of maintenance and repair. Also helping to build in efficiencies and lower costs is a single-point mooring system.
The generators convert the wave energy to electricity, which is then stabilized for grid compatibility before being sent off the device via cable. Columbia Power envisions an offshore “substation” to assemble the electricity from multiple devices before sending it to the grid
The StingRAY was designed with an eye toward avoiding some of the aesthetic concerns that can bedevil offshore wind farms, most notably in the case of the Cape Wind project off the coast of Massachusetts.
As you can see from the photo, and the “waterline” indication on the schematic, the StingRAY has a low above-water profile, which is practically nothing when compared to offshore wind turbines. The system was designed for deployment in depths of more than 60 meters, typically located at least a mile or more offshore.
Don’t hold your breath for the full scale demo project to hit the water — it’s slated for 2016 — but in the meantime you can check out more projects at the Navy’s Wave Energy Test Site (WETS — cute, right?).