Predicting wave power could double marine-based energy

Sep 10, 2012

In the search for alternative energy, scientists have focused on the sun and the wind. There is also tremendous potential in harnessing the power of the ocean's waves, but marine energy presents specific challenges that have made it a less promising resource.

It's a challenge to tune Wave (WECs) so that they are able to harvest the maximum from waves, which differ in terms of their size and force. This unpredictability leads to intermittent energy collection. WECs also need to withstand the harsh winds and storms to which they are subjected in the —storms which can destroy the devices.

Now, working with a team at the University of Exeter in the UK, Prof. George Weiss of Tel Aviv University's School of Electrical Engineering and Center for Renewable Energy has developed a that, when used in conjunction with previously-developed wave prediction technology, helps WECs calculate the correct amount of force needed to collect the maximum energy possible, allowing the device to respond to each wave individually. The system, which was recently published in the journal Renewable Energy, doubles the energy previously collected by WECs.

Calculating force

WECs, Prof. Weiss explains, have two parts—a fixed or weighted lower part, possibly attached to the ocean floor, and an upper section that moves up and down based on the motion of the water. The device collects energy generated by the resistance force between the parts. Unlike or solar panels, which collect as much or as little energy as comes their way, WECs need to adjust themselves to each oncoming wave to function properly, which requires knowledge of the characteristics of the incoming wave.

If there is between the two parts of the WEC, the upper part moves freely with the waves, and no electricity is generated, Prof. Weiss explains. On the other hand, where there is so much resistance that it suppresses movement, the device turns rigid. At both of these extremes, no energy is produced. The ideal is a happy medium based on measurements of the incoming wave.

Prof. Weiss and his fellow researchers developed a control algorithm that is responsible for setting the correct resistance force for the WEC based on the predicted wave information. A processor attached to the WEC runs the algorithm five times per second in order to determine and then implement an optimal mechanical response to the coming waves.

In the lab, the researchers have run simulations using wave data gathered from the ocean. Combining prediction technology with their new algorithm, energy collection was improved by 100 percent —double the amount of energy that WECs had collected previously.

One second warning

The most important piece of information is the height of the wave, says Prof. Weiss, which the WEC needs to know in advance in order to prepare. "You would think that the longer the WEC knows the wave height in advance, the better, but in a surprising finding, it turns out that a one-second prediction horizon is enough," he says, noting that a longer prediction time does not actually improve the energy harvest.

Their findings could not only help to improve the functioning of the WECs that are already in use in places such as the East Coast of the US and the Atlantic Coast of Spain, but could help the technology become more competitive. Currently, marine energy is fifty times more expensive to collect than the market price for the energy itself—as solar and wind energy were in their infancy, says Prof. Weiss. But with the improvement of WEC structure, performance, and mass production, it could become commercially viable. "There is a lot of untapped energy in the ocean," he adds.

Explore further: The state of shale

add to favorites email to friend print save as pdf

Related Stories

Marine energy doubled by predicting wave power

Jun 26, 2012

The energy generated from our oceans could be doubled using new methods for predicting wave power. Research led by the University of Exeter, published (27 June) in the journal Renewable Energy, could pave t ...

Scientists put spotlight on marine power

Aug 23, 2012

A team of researchers from Israel and the United Kingdom has discovered that energy produced from the planet's oceans can increase twofold when novel methods for predicting wave power are used. Presented ...

Powering Australia with waves

Aug 17, 2010

Wave energy is surging ahead as a viable source of renewable energy to generate electricity -- with Australia's southern margin identified by the World Energy Council as one of the world's most promising sites for wave-energy ...

Recommended for you

The state of shale

27 minutes ago

University of Pittsburgh researchers have shared their findings from three studies related to shale gas in a recent special issue of the journal Energy Technology, edited by Götz Veser, the Nickolas A. DeCecco Professor of Che ...

Website shines light on renewable energy resources

Dec 18, 2014

A team from the University of Arizona and eight southwestern electric utility companies have built a pioneering web portal that provides insight into renewable energy sources and how they contribute to the ...

Better software cuts computer energy use

Dec 18, 2014

An EU research project is developing tools to help software engineers create energy-efficient code, which could reduce electricity consumption at data centres by up to 50% and improve battery life in smart ...

Cook farm waste into energy

Dec 17, 2014

It takes some cooking, but turning farm waste into biofuels is now possible and makes economic sense, according to preliminary research from the University of Guelph.

Developing a reliable wind 'super grid' for Europe

Dec 17, 2014

EU researchers are involved in the development of a pan-European 'super grid' capable of dispersing wind power across Member States. This will bring more renewable energy into homes and businesses, help reduce ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.