Ireland takes first steps toward wave energy

Pelamis Wave Power announced last week that it was shortlisted as one of just two technology developers to progress to the next stage of a WestWave procurement process with Irish utility ESB for the deployment of Pelamis wave energy machines on the west coast of Ireland.

The WestWave project is a significant first step towards capturing a share of the huge wave resource off the west coast of Ireland. "The project was set up as a collaborative consortium of technology developers and partners and we’ve been able to pool some of the greatest expertise in the sector in order to pave the way for commercial wave power projects in Ireland. We’re excited to be moving into this final detailed engineering and consenting phase," says Brendan Barry, Manager of ESB Emerging Energy Technologies. 

Last year, the Pelamis P2 wave energy system was connected to the Scottish grid for an accumulated 7 500 hours, contributing 160 MW of electricity to the nation's grid. The system converts wave energy into electricity using a snake-like device deployed offshore.

Wave energy is renewable energy derived from ocean waves. It is the kinetic energy of wind interacting with water and creating waves, said Peter Asmus, a senior analyst with Pike Research, a clean tech market research and consulting firm. Energy is transferred from the wind to the waves. The longer and stronger the wind blows over the sea surface, the more powerful the sea is. The energy within a wave is proportional to the square of the wave height. 

Currently, there are three basic technological paradigms for wave energy. These are the oscillating body, the oscillating water column and the over topping device. Pelamis uses the oscillating body paradigm. Such a device, either submerged or on the surface, is moved up and down or back and forth by waves. Its motion is used to drive an electric generator. Pelamis's snake-like device that rests on top of the water, while other devices look more like buoys. 

Oscillaiting water columns (OWCs) are simple constructions that act like a piston and cylinder. As waves rise within the OWC, it replicates the action of a piston, driving a column of air ahead of it and through the turbine. Over topping devices are composed of reservoirs with up to 14 000 m³ of water filled from incoming waves. The water is released from the reservoir which drives the hydroturbines. Offshore over topping devices have wave reflectors that concentrate waves which increases the wave height.

There are a number of reasons why wave energy is preferable. The first thing that is good about wave energy is that it is renewable and environmental friendly. Wave energy projects can be run domestically and lands by seas are abundant with wave energy sources. The energy plants do not cause harm to land. There are also various ways to gather wave energy. As wave often travels very large distances wave energy is regularly out of phase with the local wind conditions.

"The best wave energy environments are along western coastlines because the largest, most consistent winds come from the west," said Paul Jacobson, ocean energy leader of the Electric Power Research Institute, a nonprofit that studies the electricity sector.

In the United States, wave power hotspots are California, Oregon, Washington and Alaska. Globally, wave energy leaders include the United Kingdom, Portugal, Australia and New Zealand. Northern Canada and southern Africa are other wave power hotspots, according to the U.S. Department of Energy.

Source: Pelamis

Featured image credit: Pelamis's oscillating snake-like device. Credit: Subseaworldnews.com