The existing technology to extract energy from the sea is still immature compared to solar or wind energy. It is not yet commercially competitive without subsidy.
The key challenges facing researchers in this area are two-fold. The first is preventing damage to wave energy devices by the hostile marine environment. The second is improving the efficiency of energy extraction from waves.
The research team from the University of Exeter and Tel Aviv University addressed these concerns by enabling control of the energy extracting devices. In collaboration with Ocean Power Technologies, the leading developer of wave energy instruments, the team focused on point absorber devices.
A point absorber is a commonly used floating device with parts that move in response to waves. Its tidal motion generates electricity that is routed back to the grid. It is known that the efficiency of this device increases when its response matches the force of the wave.
Researchers developed a system that enables such a device to predict the force of an incoming wave. This information allows a program to actively control the response required for a specific wave. This doubles the energy extraction capacity of the device.
In addition since the device can respond correctly, there is less likelihood of incurring damage. Hence, there is no need to turn it off in stormy weathers, which is the usual practice.
According to the researchers, their next step is large scale testing of the system in farms of wave energy converters. Their research is published in the June 27 issue of Renewable Energy.