Monday, March 25, 2013

Quick introduction into wind farms

Wind energy industry is the second fastest growing renewable energy industry in the world, trailing only solar energy. Thanks to a rapid rise of wind energy industry, wind farms are becoming a pretty common sight in many countries of the world. Wind farm constitutes of group of wind turbines in the same location that are interconnected with a medium voltage power collection system and communications network.

Term "large wind farms" that is lately very often used is not exactly a precise category since it can consist of few dozen to several hundred individual wind turbines connected into one wind farm. Sites on which to build wind farms are usually pre-selected on basis of a wind atlas, and validated with wind measurements (Wind Power Density).
Offshore Wind Turbines near Copenhagen, Denmark.
Many energy experts believe that future of wind farms lies in offshore wind farms, since winds are much more powerful and frequent offshore than onshore. However because of these powerful winds these wind farms need to be very strongly built to withstand rough weather condition, and this significantly increases construction costs.

Wind farms can have negative environmental impact in form of not only noise pollution but can also present danger for birds and bats, and there have been several reports where significant number of birds was killed by wind turbines (some recent studies have suggested that wind farms kill about 7,000 birds a year). However most environmentalists will still agree that positive environmental effect significantly outweigh the negative ones, and that building wins farms is one of the most environmentally friendly methods to harness energy. There have been several ideas how to protect birds and other wildlife from wind farms including an option to install new radar technology to protect migratory birds and wildlife.

Disadvantages of offshore wind farms compared to onshore wind farms are high construction costs, and complex and costly maintenance, and advantages compared to onshore farms are stronger and more stable winds, and the fact that wind turbines can be built much larger than on land which significantly improves the efficiency.

Wind Farm in Xinjiang, China.

The Gansu Wind Farm in China has over 5,000 MW installed with a goal of 20,000 MW by 2020. To get this into perspective, average nuclear power plant has capacity of around 900 MW, meaning that when Gansu Wind Farm will be finished it will have potential to generate same amount of power as 22 average nuclear power plants.

Small wind farms are usually not economically viable energy projects because of the relatively high costs so in most cases high costs outweigh the efficiency of small wind farms. Improvements in wind speed forecasting are making wind farms more efficient.

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