From time immemorial, man has understood the power of harnessing the wind. Long before modern electricity came into being, it was wind that powered pumps and enabled ships to sail. In ancient times, there were fairly primitive applications that used the wind to grind grain. Wind powered machines have long been used on farms to bring water to the surface or to drain away water, such as in the polders of the Netherlands.
These early incarnations using wind energy operated on a system of turning gears and shafts, which operated the pumps. Nowadays, while the system is more refined and effective, wind power is still generated by a series of blades that are connected to a drive shaft. By spinning the blades, the drive shaft turns an electric generator, and this produces electricity.
Many decades ago, fossil fuels became the preferred source of energy, and the world shifted its attention. Wind continued to be used but usually on individual farms or plots. It is only as the world has realized the rampant damage of coal, oil, and nuclear power that alternative ‘green’ methods of power generation are being seriously considered on a large scale, and this is why wind energy is now becoming increasingly popular.
What makes energy ‘green’?
In a nutshell, energy can be described as green if it’s produced from sources that don’t harm the environment. The sources may not be completely without impact, but green power production can be shown to greatly reduce harmful environmental factors.
Green energy usually makes use of renewable sources, such as water, the sun, or wind. Biomass is also becoming an important source of energy, which is an exciting prospect given the amount of waste that is generated on a daily basis on the planet.
How is wind energy harnessed and used?
Wind energy is collected through turbines. Generally, these turbines need a constant, average wind speed in order for them to generate electricity. The best way to make use of the wind in a particular area is to install many turbines together, which is known as a wind farm. Almost all these turbines are designed with a horizontal axis which supports an up-wind rotor with three blades. These blades would be attached to a nacelle (a streamlined casing) on top of a tall tower.
Wind is basically an air mass that is moving at a specific speed, so this energy is kinetic. The blades of the turbine transform this kinetic energy into mechanical energy as the wind causes them to spin. The mechanical energy is then converted into electrical energy by the generator at the axis of the blades.
What are the advantages of using wind power?
Wind power fulfills all the criteria of green energy in that it’s a natural, plentiful source of energy that is renewable. Wind results from temperature changes from the heat of the sun. As the sun is a constant source of energy, so then is wind. Also, wind is widely distributed throughout the planet, so there are very few parts of the earth that can’t harness this power.
Potential problems with wind power
Wind farms do use quite a bit of land, but the land beneath the turbines can be used for agricultural or other purposes. It is also possible to create wind farms off-shore as these have less visual impact and don’t occupy any land. Generally, the strongest winds are offshore rather than on land, so there is a good argument for building these farms at sea. However, these off-shore farms are a lot more energy-intensive to produce and are therefore more costly to build.
One problem raised is that wind tends to have seasonable fluctuations. What has been found, though, is that consistent amounts of wind are usually measured from year to year. Obviously it’s necessary to have a steady supply of electricity, but this issue can readily be solved through modern methods of storing electricity. It’s now entirely possible to export and import power to neighboring areas. Using weather forecasts, plans can be made for these anticipated variations.
How is wind power faring?
Wind power is constantly growing in popularity and the figures speak for themselves. In 2015, Denmark generated 40% of its electricity from wind. One report states that at least 83 other countries are using wind to supply their electricity grids, and that wind power expanded by 16% in 2014. It adds that wind now supplies 4% of worldwide electricity and over 11% in the EU.
Cost effectiveness will always be a factor and a key measurement is how long it will take for a wind farm to generate the volume of energy that it took to build the wind farm – for example, to manufacture and install the turbines. It was not surprising that land-based farms paid off the energy input faster than the farms on the open sea. However, a survey by a leading international company found that both showed outstanding results when compared with energy from fossil sources.
The study showed that a wind farm with 80 turbines can save 45 million tonnes of CO2 during its intended 25 year life cycle. If a fossil fuel source of energy was used, it would require over 1,200 square kilometers of forest to absorb the same amount of greenhouse gases. Even though wind farms can be energy intensive to set up, they make up for their energy consumption within just a few months.
Based on the figures and the studies conducted, it’s clear why the use of wind power is increasing. It’s a natural resource that is freely available and can power the planet without inflicting the enormous damage caused by unsustainable sources of energy.