How Does Wind Work as an Energy Source – know the basic facts.

How does wind energy work?

what is wind energy?
How does wind work to produce electricity is one of the most frequently asked questions about wind energy by many people who intend to go for wind power for the sake of energy security and to have a clean, cheap, reliable and balanced electricity system. This is probably due to the fact that wind power is one of the most abundant and increasingly cost-competitive energy resources and a viable alternative to the fossil fuels that harm our health and threaten the environment. Total installed wind capacity in US, through end of 2016, is more than 82000 MW and and this installed capacity supplies over 5% of US electricity which is enough for 24 million American homes in a year. Here in this article I have tried to explain  the basic facts about wind energy i.e. what is wind power, what causes the wind to blow, how does wind work to produce electricity and other related issues. All these facts will show that the wind energy system lowers our dependence on fossil fuels, reduces greenhouse gas emission, and provides a cushion against electricity price increases.

Millions of people today perceive wind power as a better way to generate clean electricity for powering homes and businesses than plants fuelled by coal, oil, natural gas or nuclear power. Because of many advantages of wind energy, according to the Department of Energy’s Wind Vision report, the wind power would double in the next five years and supply 20 percent of electricity needs of US by 2030, creating significant economic and environmental benefits along the way.

What is wind power?

Wind power is a form of renewable energy produced through machines that use wind as their power source. The term wind power or wind energy describes the process by which the wind is used to generate mechanical power or electricity. Now, how does wind work to generate this mechanical power. Using the right technology we can harness the kinetic energy in the wind, which is produced by the movement of the air when wind blows, and convert it into mechanical or electrical energy. The kinetic energy of a moving body is proportional to its mass or weight and hence the kinetic energy in the wind depends on the density of the air, i.e. its mass per unit of volume. In other words, the ‘heavier’ the air, the more energy is produced. Modern wind turbines convert this kinetic energy in the wind into mechanical power, which in turn can be converted into electricity by a generator to power homes, businesses, schools, and the like.

The answer to ‘what is wind power’ would remain incomplete unless we also discuss other basic information about this renewable energy source like what causes the wind to blow, wind energy resources, how does wind work to generate electricity and other related issues.

What causes the wind to blow.

how does wind work?

Now, let us see what causes the wind to blow. Air moving between different pressure zones is called wind and this movement of air is what we call wind flow. The next question comes how atmospheric pressure zones are created causing wind to flow. Solar radiation heats every part of the surface of the earth unevenly because of different formations of the earth’s surface, including land and water and rotation of the earth. The rotation of the Earth affects the direction of wind flow. As a result of this uneven heating the air above the Earth surface also heats and cools at different rates. As the air density is inversely proportional to temperature this uneven heating creates atmospheric pressure zones. The hot air which is less dense rises through cold air, reducing the atmospheric pressure near the Earth’s surface which draws in cooler air from high pressure areas to fill the void. The kinetic energy produced by this movement of the air when wind blows is converted to mechanical power or electricity with the help of Wind Turbine. Approximately 2% of the heat radiated from the sun and reaching the earth is converted into wind energy.  Thus wind energy is basically a form of solar energy.

Wind energy resources

Wind energy can be produced anywhere in the world where there is wind current with consistent force. Wind is usually measured by its speed and direction. How fast, how often, and when wind blows — play a significant role in wind power generation cost. These resources are compiled from wind-related recorded data by the local meteorological station.

The power output from a wind turbine depends upon the speed of the wind. The output rises as a cube of the wind speed i.e. if wind speed doubles, the power output increases eight times. Wind turbines operate over a limited range of wind speeds. If the wind speed is too low, the turbine won’t turn, and if it is too high, the turbine shuts down to avoid being damaged. The wind statistics collected from the local meteorological station, therfore, give an idea about the best sites to locate wind farms according to the best wind resources.

How does wind work as an energy source?

how does wind energy work?

The short answer to how does wind work as an energy source is that wind turns large turbine blades, which spins an electromagnetic generator shaft and produces electricity. Wind is one of those practically inexhaustible sources of energy since it is a form of solar energy as explained above. Therefore, from this explanation of how does wind energy work it is clear that as long as the sun shines and the wind blows, the kinetic energy from movement of the wind can be harnessed for producing electricity and for other useful purposes.

How does wind work to make a turbine to harness energy from the wind

The kinetic energy in the wind is converted to electricity by building a tall tower, with 3 propellers-like blades called rotor (Wind Turbine) on the top (as shown in the picture). When the wind blows on the angled blades of the rotor, it causes the rotor to spin. Since the rotor shaft is connected to a generator through a gearbox, when the rotor spins, so does the generator and the generator uses an electromagnetic field to convert the wind’s kinetic energy into electrical energy. It would be evident from the above explanation of how does wind work to rotate a turbine, the speed of wind plays a significant role to maximize power production and in turn to reduce generation cost. If the wind is too slow the Wind Turbine fails to rotate, on the other hand if it is too fast, the turbine will automatically shutdown itself to avoid being damaged. An average wind speed of 14 to 15 miles per hour is typically needed to economically generate power from wind energy. The power output from a wind turbine rises as cube function of the wind speed. In other words, if wind speed doubles, the power output increases eight times. Therefore, higher-speed winds are more easily and cheaply captured.

 Wind is a clean source of energy

From the explanation of how does wind energy work it is also evident that one of the main advantages of wind energy is that there is no scope of producing any toxic emission and none of the heat-trapping emissions that contribute to global warming, in the process of converting kinetic energy in the wind to electricity. Wind energy is, therefore, a clean energy source that doesn’t pollute the environment like non-renewable power sources that rely on combustion of fossil fuels, such as coal, oil or natural gas. Combustion of these fossil fuels for electricity generation produces atmospheric emissions that cause acid rain or greenhouse gasses (Carbon Dioxide, Methane, Nitrous Oxide and Ozone).

Wind Energy Technology Basics

It is clear from the description of how does wind work to produce electricity, wind turbines can be used separately, or they can be linked to a utility power grid or even can be operated in combination with a photo-voltaic (solar cell) system. To operate as a bigger source of energy, a number of wind turbines are built close together to establish a wind plant. Several electricity suppliers today use such wind plants to supply power to their consumers.

A grid-connected wind turbine can help us to reduce our consumption of costly utility-supplied electricity for lighting, appliances, and electric heat. If the wind system cannot deliver the amount of energy we need, the utility makes up for the shortage. When the wind system produces more electricity than we require, the excess energy can be sold to the utility through the available interconnections where switching takes place automatically.

Stand-alone system is suitable for those whose grid connection is not available or can only be made through an expensive extension like homeowners, farmers, and ranchers in windy areas, as a way to cut their electric bills. But there are times when the wind turbine is not producing electricity (i.e. when the wind is not blowing) and you require backup system to supply power. During such times most of these stand-alone systems provide power through batteries and/or an engine-generator powered by fossil fuels like diesel.  However, for this the storage capacity of the batteries must be large enough to supply electrical needs during non-charging periods. Battery banks are typically sized for one to three days of windless operation. Here, the power from the wind turbine is stored into the batteries instead of feeding into the mains grid. A power inverter is connected to these storage batteries which convert the DC input voltage from the battery system to 240 volt AC output voltage to power and run the home appliances.

A 1.5 kW wind turbine is typically needed to meet the needs of a home requiring 300 kilowatt-hours (kWh) per month, in a location where annual average wind speed is around 14-mile-per-hour.

You may also like to read: How do Solar Panels Work to convert sunlight into electricity

Conclusion

From the above discussion on how does wind energy work it is clear that for rural homes with a good wind resource, wind power can be a clean and cost effective alternative source of electricity. Though, it is apparent from the explanation how does wind work to produce electricity that wind power has high upfront construction costs but once running, the fuel is absolutely free. Since producers of fossil fuels like gas and coal have to pay for their CO2 emissions, wind power becomes comparatively cheaper as its CO2 costs are zero in addition to the savings from the zero-fuel costs involved in producing wind power. This in effect means lower electricity prices for the consumers. By 2020 the estimated average total cost of electricity using onshore wind should be about $75 per MWh as against $95 per MWh for conventional coal.

It would be evident from the above facts that the polluting non-renewable power sources shall become comparatively too expensive and gradually lose out to wind power in competition in the electricity market.

No comments.

Leave a Reply