13/05/08
Wave energy has yet to be demonstrated as a possibility for large-scale commercial power generation. However, with the rising costs of fossil fuels and increasing environmental concerns, a competitive wave industry, if developed, could be one of the most environmentally benign of the renewables. The most practical application for wave energy in the short to medium term could be on small, remote islands without easy access to fossil fuel shipments or the need for long transmission lines. The potential for these sorts of small but locally important projects seems highest in the UK, where wave power density is high and much of the research is centered. Ocean Power Delivery, the Scottish company that provided the 2.25 MW installation in Portugal, is planning a 3 MW project in Orkney, the small island systems off the north coast of Scotland (OPD 2007). There has also been research into potential uses for wave energy other than electricity, most notably desalinization and hydrogen generation.
Wave energy conversion device for DESALINIZATION
An impulse-type “wave motor” employs a seabed-mounted or supported structure mounting a wave energy absorbing panel on a hinged lever arm for reciprocation motion to obtain optimal absorption of wave energy from wave motion in the sea. For deepwater wavelengths of L, the panel is optimally positioned in a region within L/2 depth from the sea surface. The panel motion is coupled by a connecting rod to a fluid pump which generates a high-pressure fluid output that may be used to drive a reverse osmosis desalination unit or to produce other useful work. Seawater or brackish water may be desalinated through reverse osmosis membranes to produce water quality for consumption, agricultural, or other uses. The submerged operating environment of the device in a region of one-half the design wavelength provides the maximum available energy flux and forced oscillations. The pump may be of the positive-displacement piston type, plunger type, or multi-staging driver type, or a variable volume pump.
--seokting
--
13/05/08
Storing and Transporting Energy as HYDROGEN (hydrogen generation)
Offshore wind, solar, and wave energy do not always produce energy at the time at which it is needed. In addition, the energy produced at remote offshore locations using these technologies and ocean current technology must typically be brought to onshore consumers. To address the sporadic nature of energy production from these sources at offshore locations, feasible methods for storing excess energy until it can be used and for transporting it must be developed. Currently, the most attractive approach is the use of hydrogen as a storage medium. Hydrogen can be generated on location on a variety of scales, and it can be stored and transmitted for later consumption in fuel cells in vehicles or converted into electricity. At this time, however, hydrogen is not being used to store or transport energy produced with ocean energy technologies in commercial applications.
HYDROGEN PRODUCTION
(Offshore electrolysis-hydrogen generation unit)
In future commercial applications, hydrogen could be produced offshore at the point of energy generation in a co-located facility, or it could be produced at an onshore location, utilizing the energy generated at the offshore power generation facility. Because all four alternative energy sources under analysis in the OCS Alternative Energy Programmatic EIS are capable of producing electricity, electrolysis is currently the most viable means of producing hydrogen from any of the four alternative energy sources. Electrolysis involves the dissociation of water into hydrogen and oxygen by passing a current through an electrochemical cell, and has been available commercially for decades.
--cassandra
--
06/06/08
But of course, after all that, we still have to come back to the most essential and prominent use of wave energy: the conversion of this kinetic energy into electrical energy!
CONVERSION TO ELECTRICAL ENERGY
During the next 20 years, experts foresee a need for 1500 GW. of additional power supply to meet new demand. This equals to 15000 power plants that are 100 MW each and 59 million barrels of oil consumed in each day. The world Bank estimates that the developing countries alone will need to spend $100 billion each year for the next 30 years installing new power plants most of which will be in the equatorial Zone. These are astronomical figures that could mean enormous quantities of fossil fuel and 2.2 billion tons of CO2 release to the atmosphere per year. Hence, an urgent need to switch to alternate energy. Among the alternate energy resources, wave energy is considered as one of the promising alternate energy resources that has high availability factor (day & night) compare with other resources such as Wind energy or Solar energy.
It has been estimated that if less than 0.1% of the renewable energy available within the oceans could be converted into electricity, it would satisfy the present world demand for energy more than five times over.
Therefore, it is important and worthwhile to conduct experiments on wave energy harnessing techniques to tap the wave power to generate electricity.
The electricity generated in this way (using 'green' energy / renewable sources of energy) is usually used to run large factories and companies, which may otherwise cause the depletion of fossil fuels that are non-renwable. This, therefore, facilitates the progress made by
Otherwise, the generated electricity may also be supplied to households in order to power appliances used in daily life, as well as effectively reduce the already large amount of carbon emissions that the particular country is giving out. This an effort to reduce the harm we are doing on Mother Earth can help save up to 10,000 tonnes of carbon dioxide each year.
--yuwei
Edited and reviewed by the people who wrote it:
21/06/08
No comments:
Post a Comment