Wave energy is moving off shore. Although a number of successful devices have been installed at shoreline locations, the true potential of wave energy can only be realized in the offshore environment where large developments are conceivable. In terms of power potential, offshore locations offer more than shoreline locations. The negative side is that devices in offshore locations have more difficult conditions to contend with. Shore line technologies have the benefit of easy access for maintenance purposes, whereas offshore technologies are, in most cases more difficult to access. Improving reliability and accessibility are, therefore important in commercialization of wave energy harnessing.
Shoreline wave energy is limited by fewer potential sites & high installation cost whereas a 50 MW wave farm is conceivable on offshore locations. No shoreline wave energy converter is able to offer such potential for deployment in this way. Deployment costs for shoreline wave energy devices are high because they are individual projects and economics of scale are, therefore, largely inapplicable. Shoreline devices only account for 8% of forecast capacity between 2004-2008. Offshore represents the most significant wave energy sector, with 58% of all forecast capacity. Offshore is so dominant because devices are typically of a larger capacity than their nearshore compatriots.
Ocean Power Delivery Pelamis
In the present time OPD is viewed as market leader which has developed ‘pelamis’ concept. The ‘pelamis’ is made up of five cylindrical segments connected by hinged joints. The wave induced motion on these sections is resisted by hydraulic rams which pump high pressure fluid through hydraulic motors via smoothing accumulators to drive electric generators. The power is fed through a cable to a junction on the sea floor where a single cable carries the electricity to the shore. The
first full-size pelamis has a rated capacity of 750 KW.
Wave Dragon A/S – Wave Oragon.
Wave Dragon is the first operational grid connected offshore wave energy device, installed in Denmark. The prototype wave dragon has an output of 20 KW. The device is under study to gain more knowledge & experience. The different models of 7MW, 4 MW & 11 MW capacity are proposed for the different levels of wave resource.
Wavegen – Limpet
Wavegen is one of the market leaders in wave energy, having installed their Limpet shoreline devices in Scotland in 2000. It is also developing technology which generates power from wave energy, whilest also acting as an artificial reef. The device which rests on the sea bed, could in some cases and coastal protection. The technology is of particular benefit to island communities.
Environmental Impacts
Small-scale wave energy plants are likely to have minimal environmental impacts. However some of the very large-scale projects that have been proposed have the potential of harming the ocean ecosystems covering very large areas of the surface of the oceans with wave energy devices would harm marine life and could have more wide-spread effects. Changes in waves and currents would most directly impact species that spend their lives nearer to the surfaces. The dampening of waves may reduce erosion on the shoreline and may have damaging ecologies effects, that need to be scientifically proved.Wave energy is promising holds huge potential to reduce reliance on fossil fuels. Carefully choosing sites that can withstand the alterations to the environment caused by power plants will be crucial to effectively develop these technologies without harming the ocean.
