Scotland’s AWS Energy has announced results about 20% better than expected for its Archimedes Waveswing, a prototype wave energy generator that has been tested at sea at the European Marine Energy Center (EMEC) in Orkney, Australia. course of the last six months.
The Waveswing is a cylindrical metal buoy attached to a single point on the ocean floor. In operation, it stays below the surface and reacts to changes in water pressure. As a wave passes overhead, the increased pressure pushes down on the upper “float” section of the device, causing it to slide downward relative to the lower “silo” section, with a rolling seal ensuring that no water enters.
This linear motion in this “telescopic box” compresses the air in the Waveswing device, creating an air spring to push the floating section upward as the wave rolls forward. As the float moves up and down, it drives a hydraulic motor, which converts linear motion into rotation, and a regular electric generator draws power from the up and down strokes.
The Waveswing Wave Energy Converter Explained
The device can be raised and lowered on its tether for maintenance and deployment, and there is also a facility to regulate the air pressure inside the cylinder, effectively adjusting the air spring to make the most of the wave conditions.
AWS reports that “during a period of moderate wave conditions” at the EMEC facility, the prototype machine captured an average of 10 kW, with peaks of up to 80 kW, against its rated capacity of 16 kW. The test also demonstrated that the Waveswing can be fully deployed from seated dock to fully operational in less than 12 hours, and can survive Force-10 gale conditions.
The power delivered frankly seems surprisingly low given the size of this machine. It is 7 m (23.0 ft) high fully extended, with a diameter of 4 m (13.1 ft) and weighs 50 tons; it makes quite an impressive sight as it is driven down the road on a trailer.
But this is not the commercial device. AWS says these units will be configurable for powers between 15kW and 500kW — though it’s unclear whether these half-megawatt versions will need to be physically larger, or if so, by how much. The company sees commercial deployments taking the form of multi-absorber structures, which could see 20 of the most powerful units packed into a 10 MW platform.
According to IRENA, there is enough energy in the movement of the ocean – specifically, in wave energy as opposed to tidal energy – to meet all of the world’s energy demand. But the technology here is in its infancy; there are many pilots and prototypes, but very few commercial installations. And since nothing has been proven yet, there is a fascinating proliferation of different designs, all in search of a solution that is cheap, easy to deploy and maintain, environmentally friendly and capable of producing energy. power in all kinds of conditions for decades despite the brutal corrosive onslaught of salty seawater and muddy biofouling.
Efficiently harnessing wave energy could drastically reduce the prices of renewable energy networks; these things won’t turn off at night like solar, or when the wind drops, so they can reduce the need for long-term and short-term energy storage that a grid needs to guarantee a reliable power supply. This, as suggested by CSIRO modeling for Wave Swell Energy’s UniWave generation systems, could reduce upfront CAPEX (capital expenditure) on multimode renewable energy systems by up to two-thirds.
It is therefore an area of immense potential and consequences, but also in which it seems that we will have to continue to be patient. See the Waveswing prototype in action in the video below.
From concept to reality v2
Source AWS Ocean Energy