Sunday, July 23, 2006

Wave Power

With the declining of fossil fuel resources and increasing concern of environmental degradation, there is ever growing interest and research into clean and renewable forms of energy. The vast majority of interest is on solar and wind power (and of course biofuels, but I'm talking about electricity generation), however there are other less popular forms of renewable energy that tend to be somewhat overlooked. One such form is solar tower technology, but another serious contender is wave power.

Based on the recent results of a new design by an Australian company Energetech, wave power appears to be one of the most promising sustainable energy sources in development. The results of the Port Kembla project indicate that this design could even be competitive with fossil fuel sources.

Some excerpts from their website:

Past laboratory studies and the analysis of an earlier trial deployment at Port Kembla had indicated the Energetech technology was capable of producing an annual energy output of at least 500 MWh at Port Kembla. However, this latest trial indicates the technology is capable of producing more power and fresh water than has previously been claimed. Based on the recent test results, a full scale project should power up to 1500 homes, or produce three million litres of water per day per production unit.
This is very encouraging, as the outcome of the trial ensures the economics of the design will be competitive not only with other renewable energy forms, but also with full cost fossil fuel sources.
Moderately good wave climates should produce power using first generation systems at a cost of around 10 cents US per kWh, and ideal sites at a cost around 5 cents. Over time, on moderately good sites, with capital cost savings from second generation designs, we can see the technology regularly delivering electricity at around 4 cents US kWh
Wave energy is:
• truly renewable - inexhaustible and occurring from natural phenomenon
• the most consistent of the intermittent renewable energy sources
• non-emitting - no emissions of harmful pollutants result from its use
• consumes no fuel in the operation of the system
Ocean waves contain enormous amounts of energy, but the energy in each crest is generally spread out along it. If all the energy could be transported to one point it could be harnessed far more readily.
It is possible to focus all the energy of a plane surface gravity wave crest, the type you see breaking on the beach, on to a single point using a parabolic wave focusser. The section of the wave is reflected by a parabolic wall and converges on the focus of the parabola. As the wave converges, the crest height grows to a maximum in the focus area.
Approximating what the device will produce in the way of power depends on the amount of energy extracted based on sea conditions on a particular day.
An illustration, however, may be useful. Consider a parabolic focuser with dimensions of 40 metres width, 20 metres length, and a focal length of 5 metres. Assume a coastal wave crest amplitude of 1 metre. This would render in the vicinity of ten million joules of energy for extraction from each wave. This equates to between 1 and 2 megawatts of power.

With the coming energy crisis that the world is bound to face as oil production inevitably peaks, we must actively pursue all avenues of possible solutions. And in countries where there are large costal populations (isn’t that everyone?), wave power looks like it could be a viable component in our future energy needs.

And then there is the issue of fresh water. In places such as Australia where most of the country is in severe drought, and where almost the entire population is located in coastal regions, wave power, with it’s ability to produce both fresh water and clean energy, seems like an essential technology to develop.

Solar power and wind power are great technologies, but perhaps it’s time we started paying attention to all of the available solutions? Wave power, especially with this new design, has the potential to be a primary resource for Australia and much of the world.


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