Off-shore wind farms refers to the placing of huge wind turbines on seas and oceans! But unlike tidal generators, these wind turbines are not submerged into the water. They are fixed above the water level, with a supporting structure that goes deep into the oceans. This support structure is one of the major differences between on-shore (land-based) and off-shore wind turbines. Otherwise, the two of them are quite similar.
Off-shore turbines maybe constructed closer to the coast as areas with depth less than 30 meters is more practical for locating an off-shore farm. However, off-shore turbines can also be constructed in deeper locations using the concept of 'floating wind-farm'.
Advantages of Off-shore Wind Farms/Wind Turbines:
- Wind is stronger and more frequent in the sea.
- Hence, higher capacity wind turbines can be installed in the sea, when compared to land. Higher capacity wind turbines are much more efficient than smaller ones and overall, lesser number of such turbines are sufficient to achieve the required capacity of an off-shore wind farm. The average capacity of installed off-shore wind turbines in Europe is around 3 MW.
- To set-up a wind farm, a considerable amount of land is required. But since off-shore wind farms are located in the sea, no land is wasted. Land can always be used for some other purpose like constructing buildings, farms, etc.
- Since off-shore wind turbines are going to be located some distance away from the land, aesthetic issues like obstruction to scenery/landscape view, can be avoided.
- Off-shore wind turbines could be located near a coastal city and the electricity generated by them could be used at the city itself, thereby avoiding long-distance transmission losses, which could be considerable.
- Off-shore wind sector has the potential to create a lot of jobs and it can bring in a lot of investments. Since these wind turbines are typically large, manufacturers might want to utilize local manufacturing facilities and source raw materials locally.
- Electricity cost could come down or at least stay the same because wind (the source) is a free resource, and hopefully, will always be free. Unlike the cost of coal/oil, cost of wind does not keep increasing! Off-shore wind is a one time investment.
- Foundations of wind turbines (inside the sea) could be developed as an artificial reef for marine species, thereby increasing the marine activity within the region.
- Wind is a renewable source of energy and harnessing wind energy does not result in any carbon emissions. In fact, DoE (US) estimates that for every 1 GW of wind power, 1.8 million metric tonnes of carbon emissions are saved. There is absolutely no pollution because of wind farms.
- Construction costs for off-shore wind turbines are higher than on-shore wind turbines due to the added costs of foundations/sub-structures. In 2010, DoE (US) estimated that the cost of off-shore wind turbine could be around $2400 per KW, compared to $1650 per KW for on-shore wind turbine.
- Environmental objections (like obstructions to marine life migration, bird migration) and commercial objections (like obstructions to the passage of boats, fishing) could be raised against off-shore wind farm projects. But some of these objections are misplaced and some of them have solutions.
- Specialized vessels (large ships) and machinery are required for construction of off-shore wind farms. Trained manpower with required skills is another requirement.
- Maintenance of off-shore wind turbines are complicated than on-shore wind turbines. Remote monitoring and management is always possible, but special vessels are required if a service personnel is required to visit the turbines.
- Accurate simulations models to predict the off-shore wind patterns are still in development.
- Off-shore wind turbines should be strong enough to withstand storms, cyclones and hurricanes. But, they can be strong enough and the ones currently installed, are.
- Permits and clearances might have to be obtained from multiple government departments to set up off-shore wind farm projects.
By the end of 2011, 3 GW of off-shore wind farm capacity has already been installed in Europe. Even our neighbor China has completed the implementation of a couple of off-shore wind turbine projects near Shangai. It's high-time we too consider implementing a pilot project to understand this technology, its advantages and disadvantages, better.
References:
- http://en.wikipedia.org/wiki/Offshore_wind_power
- http://www.zefirteststation.com/en/offshore-wind-energy
- http://dwwind.com/resources/benefits-of-offshore-wind
- Mary Rock, Laura Parsons, "Fact Sheet: Off shore wind energy", October 2010, Environmental and Energy Study Institute
