A wind farm is a collection of wind turbines in a single location and is used for the commercial production of electricity. There are two types of wind warms: the onshore wind farms and the offshore wind farms. As the name implies onshore wind farms are wind farms located on land whereas offshore wind farms are located in the water (in the sea, or in the lakes). This article is about the offshore wind farms.
The components of an offshore wind turbine are similar to those of the onshore wind turbines (see wind turbines basics in a nutshell). The only main difference is the tower structure that must be located in the water. Most offshore wind turbines are placed in waters up to 100 feet (30 meters) deep and their tower structure
usually consists of large single column structures (monopiles). For wind turbines in waters up to 260 feet (80 meters) deep tripod tower structures are used. In deeper waters, it is not possible to use bottom-mounted towers so floating wind turbines are being under experimental development.
There are many advantages associated with offshore wind farms. Above all, offshore wind farms take advantage of the stronger and more constant winds that exist in the sea. As a result the offshore wind turbines are more efficient, they can produce more electricity and they can maintain higher levels of electricity generation for longer periods of time.
Moreover, offshore wind farms eliminate some of the disadvantages of onshore wind farms. Particularly, onshore wind farms are being ‘accused’ to be noisy and to be obtrusive to the environment and to the nearby communities. With offshore wind farms, noise and visual impact is eliminated whereas the environmental impact is significantly reduced, allowing for the designers of the wind turbines to produce larger wind turbines with longer blades that can effectively produce more electricity.
The main disadvantage of offshore wind farms is that they require higher installation costs, higher connection costs to the grid and higher maintenance costs. This is because offshore installations pose many and unpredictable challenges and proximity to the site is more difficult.
Offshore wind turbines take advantage of capacities in the range of 5 – 7MW whereas onshore wind turbines in the range of 1 – 3MW. Offshore wind turbines have a lot of potential in the future as continuous development will further improve their efficiency and at the same time make them more cost effective. This is why in US offshore wind power is considered a key towards achieving the goal to generate 20% of the country’s needs by the year 2030. Currently, in US there are no offshore installations but there are plans to heavily invest in this technology. On the other hand, European countries are heavily investing in offshore wind farms with UK and Denamrk being the leaders. Today, the world’s largest offshore wind farm project is the Thanet Offshore Wind Project in UK with 100 wind turbines and power generation of 300 MW.
As the leading countries in renewable energy investments (US, EU and China) implement their plans to cover a big percentage of their power generation from renewable energy, in the next decade we expect to see a lot of development in offshore wind power as it is expected to be in the center of their strategic plans.
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