Simpler, cheaper renewable energy system uses waves to inflate rubber
Although we've seen a number of experimental wave-power systems in recent years, a new one is claimed to be less expensive and to incorporate fewer moving parts, while still remaining durable in rough seas. It's known as a Dielectric Elastomer Generator, or DEG for short.
The prototype system was developed by scientists at Scotland's University of Edinburgh, and at Italy's Universities of Trento, Bologna and Scuola Superiore Sant'Anna Pisa. It basically consists of an anchored vertical cylinder which a column of air is trapped inside of. The top of the cylinder is sealed with a rubber membrane, while the bottom is open to the surrounding ocean.
As the crest of a wave passes around the device, it forces water up inside of the cylinder. This pushes the trapped air up, causing the membrane to expand. Once the device is in the trough of the wave, the water level inside the cylinder drops – this causes the membrane to be sucked down, as negative pressure is created inside the DEG.
Because the rubber incorporates layers of dielectric material, it generates voltage both as it puffs out and as it's pulled down. "The membrane is charged at its maximum inflation or deflation, it is discharged at the rest position," U Edinburgh's Prof. David Ingram tells us. "So energy is generated both from the wave crest and the wave trough passing the generator."
In a commercial version of the system (illustrated above), the resulting electricity could be relayed to shoreside communities via underwater cables. A small-scale prototype has already been successfully tested in a wave tank at the university – based on its performance, it is estimated that a full-size device could generate the equivalent of 500 kilowatts of electricity, which would be enough to power about 100 homes.
It is hoped that within a matter of decades, "fleets" of the DEGs could be deployed in areas such as the Scottish coastline, where powerful waves are plentiful.
A paper on the research was recently published in the journal Proceedings of the Royal Society A.
Source: University of Edinburgh