Wind energy
Introduction
Ever wondered how wind is formed? Well, the sun heats the Earth’s surface unevenly, creating areas of high and low pressure. Air always moves from areas of high pressure to areas of low pressure, thus generating wind 1. Since wind is in plentiful supply, it’s a sustainable resource for as long as the sun’s rays heat the planet 2.
Wind turbines (formerly known as windmills), collect and convert the kinetic energy that wind produces into electricity to help power the grid 3.
Types of wind energy
There are two types of wind energy: onshore and offshore energy 4. They both generate wind in the same way, the only difference being where the wind turbines are positioned, their size and how the electricity they generate is transferred 5.
Onshore6 wind power is generated via wind turbines constructed and situated on land (wind farms). The turbines are driven by the natural movement of the air. They are constructed in less populated areas where buildings and obstacles don’t interrupt the flow of air. An example of this is the Ngong Hills wind power station in Kenya.
The wind makes the blades spin creating kinetic energy. A generator that is part of the wind turbine converts this kinetic energy to electrical energy.
Offshore wind energy uses the wind at sea, which is stronger and more consistent than the wind on land. The wind moves the turbine blades around the rotor. This spins a generator and creates electricity. Underwater cables carry the clean energy to an offshore substation. From there it moves through the electricity grid, and into homes, towns and workplaces7.
Wind is believed to be the most efficient way to harness renewable energy due to two main reasons. Firstly, windmills can be installed in farms that can also be used for agriculture, offering flexibility. Secondly, the manufacture and distribution of wind turbines does not have a direct relationship with water usage and these turbines do not need fuel to function.
According to the Statistical Review of World Energy report, 20248, China was leading the world in wind energy installations, with a wind turbine capacity of 441,895 megawatts. It was followed by the US at 148,020 megawatts and Germany at 69,459 megawatts. Ireland installed a capacity of 4807 megawatts of wind energy, of which 4782 megawatts were onshore and 25 were offshore.
While wind energy is a clean energy 9 source, it also presents certain challenges. Wind turbines can impact wildlife both directly, via collisions, as well as indirectly due to noise pollution 10. Additionally, given that wind farms are set up in less populated places (mostly rural areas) in order to avoid obstacles, installation and transmission of electricity can be very expensive. It is also wise to have a backup source of energy on days when it is not windy enough.
Next: Geothermal energy
Footnotes
An electrical grid (or electricity network) is an interconnected network for electricity delivery from producers to consumers.↩︎
The best way to remember this is to note that shore means the land along the edge of the sea, the ocean or a lake. So onshore (on land) and offshore (not on land so maybe on sea? on lake?)↩︎
Energy that is produced from renewable, natural sources that generate little to no pollution or greenhouse gas emissions↩︎