"The available global Ocean Energy resource is in the same order of magnitude as the present electricity production worldwide." – IEA-OES.
Ocean waves are created by surface winds. The growth of the waves depends on the strength of the wind, its duration, and the open ocean distance (fetch) over which it blows. The most powerful and consistent waves are created by strong prevailing winds in high latitudes. These waves propagate over long distances with little energy loss, to deliver consistent and abundant supplies of readily useable energy along populated coastlines.
It has been calculated that ocean waves transport up to 80,000 TWh per year (IEA-OES, 2004). This amounts to over four times the annual global production of electricity.
The power available at any particular location is generally reported in terms of kW/m, or the average power available in the waves per metre parallel to the shoreline. Suitable sites with values of 20kW/m or greater are generally viable for economic production of electricity from waves, depending on market pricing and local policy. Studies performed by DTI (UK), NRC (Canada), and CSIRO (Australia) have demonstrated that vast regions of coastline exhibit conditions that meet or exceed these requirements.
"At energetic sites, wave power exhibits a high degree of persistence, which means that power output in the next hour is likely to be similar to the last" – Carbon Trust. This persistence, or consistency, suggests that wave energy systems can be sized such that their average output is nearer to the peak capacity (relative to wind or solar), resulting in generally higher capacity factors (40-45%) and potentially superior economics.
There are literally thousands of sites worldwide that exceed the required level of available power, with large regions of Australia, New Zealand, USA, Canada, Western Europe, India and South Africa all well-suited for wave energy development.
BioPower Systems maintains a database of regional characteristics for potential site development, including wave power resource, local and regional policy and pricing framework, available infrastructure, and potential commercial partners. The information is used to consider future development options. close [x]
Tidal Current Energy
The tides create movements of water that are accelerated into strong currents near the periphery of the oceans, or through straits and narrow passages between islands and other landforms – IEA-OES, 2003.
These strong tidal flows, or tidal streams, contain kinetic energy that can be converted to useable electricity. Commercially viable development sites are typically characterized by a peak current speed of 2.5m/s or greater. In many locations, the peak current speed exceeds 5m/s.
Studies to assess the marine current resource have been carried out in the UK (DTI, 1993), European Union (CEC, 1996), and in some of the far-eastern countries (CEC, 1998). Within Europe, the resource is strongest and therefore of special interest around the UK, Ireland, Greece, France and Italy. In China, it has been estimated that 7000 MW of tidal current power is available. Locations with high potential have also been identified in the Philippines, Japan, Australia, Northern Africa and South America – IEA-OES, 2003.
The high load factor and predictability of tidal currents suggests that capacity factors in the range 40-50% range would be practical. This indicates the potential for competitive electricity supply where suitable conditions exist.close [x]