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22/05/08
ENVIRONMENTAL IMPACTS
Positives:
1) Little to no chemical pollution during operation and little to no land use (Lemonis 2004). These devices would have very low greenhouse gas emissions estimated at 11g of CO2 per kWh for near-shore schemes (Duckers 2004), and 21.67g per kWh for the off-shore Pelamis device (Banjeree et al 2006). This compares to a release of about xx KG of CO2 per kWh for coal-fired electricity production. Environmentally benign and non-polluting: no fuel, no exhaust gases, no noise. Minimal visual impact.
2) As a renewable and highly sustainable non-nuclear source of energy (green energy), wave energy is naturally replenished, in a sense that they cannot 'run-out', is in constant supply over time and that has environmental and social impacts that are generally more benign that that of fossil fuels.
3) Wave power is predictable and dependable, thus humans can be armed with the ability to accurately forecast the wave power spectrum days in advance. This way, they can be well prepared for the next strong currents in order to harness the maximum amount of energy possible and obtain the energy needed for conversions to other forms.
4) There are many ideal locations in Europe, North and South America, Africa, South Pacific Ocean and Asia where high power densities exist close to highly populated areas, therefore there is potential for wave energy to be harnessed and put to efficient, effective use to support many many households, especially when it comes to the generating of electricity.
Negatives:
1) These devices require very high construction costs. From a net energy perspective, the energy required to build the infrastructure may outweigh the small amount of electricity wave projects are capable of producing in the short term. Severe storms have dashed the hopes of some earlier projects, probably before serious energy has been returned.
Wave energy is at an early stage of development and is therefore still relatively expensive when compared to other sources of electricity. The House of Commons Science and Technology Committee concluded in 2001 that a true picture of the likely cost of wave power will only be available after the industry has matured and large devices have been operating for some time. However, the cost of wave energy has fallen over the past 10 to 15 years and ongoing technological developments mean the predicted costs of wave energy are continually being reduced.
2) They may also alter coastlines by changing energetic patterns of waves (Lane 2007 may generate various environmental impacts, most of which are unknown. Some wave energy devices may affect the natural flow of sand and other beach sediment and so would require sensitive siting but the installations could also potentially benefit the environment by creating safe havens for fish and helping to reduce coastal erosion.
3) Other potential impacts, such as disruption of marine habitat and fish migration patterns, and sedimentation, are generally agreed to be minimal, but important considerations on an individual project basis.
4) There are also noise impacts due to some devices used to harness wave energy.
5) Though the wave devices have no emissions during generation but the energy associated with the construction of the device does have small associated emissions.
6) There has been some concern about aesthetics and disruption of fishing, shipping, and boating. These impacts would occur in both construction and operation.
--yuwei
Edited and reviewed by yingshi on 19/06/2008
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11/06/08
Public Perception
Public attitudes toward ocean energy technologies are unknown, but clean energy is generally perceived in a positive light because of its environmental and other benefits. Successful demonstration projects and careful siting practices will help ensure public acceptance of these emerging green energy options.
All new and unfamiliar technologies may initially be viewed with skepticism. In addition, concerns have been expressed over the potential impacts of shoreline and nearshore wave energy devices related to aesthetics as well as sediment transport and other physical processes. These and other technologies may also impact recreational and commercial activities.
OVERCOMING 'negative' point number ONE, which is the only one that can be solved at all
Wave energy is already competitive in niche markets, such as remote islands, which are often reliant on expensive (and environmentally detrimental) diesel generators. The development of wave energy alongside other technologies - fish farms, harbour defences, desalination plants or wind farms could further reduce costs. In addition, there are potentially many opportunities for the wave energy sector to collaborate with the wind power industry, both on joint projects (e.g., combined offshore facilities) and by addressing common problems such as connecting the electricity they generate to the National Grid.
--yuwei
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17/06/08
Challenges
These are some of the challenges to deploying wave power devices:
Efficiently converting wave motion into electricity; generally speaking, wave power is available in low-speed, high forces, and the motion of forces is not in a single direction. Therefore, it is a challenge to ensure most of the wave energy which acts in different directions to be converted to electrical energy. Besides, as solar energy is converted to wind energy and finally to wave energy, much energy is lost to the surroundings in the process of conversion and hence, it is very important to prevent further loss of energy. Most readily-available electric generators operate at higher speeds, and most readily-available turbines require a constant, steady flow.
Constructing devices that can survive storm damage and saltwater corrosion; likely sources of failure include seized bearings, broken welds, and snapped mooring lines. Knowing this, designers may create prototypes that are so overbuilt that materials costs prohibit affordable production.
High total cost of electricity; wave power will only be competitive when the total cost of generation is reduced. The total cost includes the primary converter, the power takeoff system, the mooring system, installation & maintenance cost, and electricity delivery costs.
--yingshi
Edited and reviewed by the same people who wrote it:
26/06/08
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