8. Wind Power

Since the time of the ancient sailboats and windmills, the power of the wind has been harnessed for ship propulsion and the performance of mechanical work. In the modern era, wind has been increasingly used for the production of electric power. In the first decade of the twenty-first century alone, the production of electricity from wind power worldwide has increased by a factor of eight. Similar to solar energy, wind is also a distributed, renewable source of energy. The energy density of the wind is low, but wind is available in all the geographical regions of the world and its geographical distribution is more uniform than that of solar energy. Wind turbines of different sizes and designs are currently used successfully for the production of electric power. The bigger and more efficient types of these engines have blades with lengths between 20 and 50 m, are located at the top of 50–140 m towers and are becoming ubiquitous in the landscape of several OECD countries. Wind is probably the most environmentally benign energy source. In theory, it has the capacity to satisfy the energy needs of entire countries and even that of the whole planet. However, it is also an intermittent source with availability and intensity much less predictable than any other source of alternative energy. This intermittency is a significant drawback and will limit the more widespread use of wind power, unless suitable energy storage systems are developed that would store part of the energy produced during windy periods.