Offshore wind turbine. Image credit: NASA
It is fascinating to note that both hydropower and wind power rely so much on the presence of a single substance in our planet – water. Hydropower makes use of the potential and kinetic energy of falling water, while wind power makes use of the movement of air which is mainly brought about by the unequal temperature between land and the adjacent body of water.
Harnessing wind energy, although considered by critics as a more costly exercise than those on traditional sources of energy, is steadily gaining popularity due to its zero greenhouse gas emissions.
Since wind does not blow constantly (and in fact, at certain times, there may be no wind at all), relying on a single wind farm for power generation may cause problems. This intermittency problem is remedied by using wind energy alongside other sources of energy.
For instance, a pumped-storage hydroelectricity can be used to store energy during times when there is an excess of supply due to prolonged high wind velocities. That is, during periods of high supply, water is pumped up to the reservoir which is typically located at an elevated location. During low supply, when winds are scarce, water can be released through turbines much like a hydroelectric plant.
In a countrywide grid or continent-wide grid, one solution to the intermittency problem is by shifting the power generation duties of different wind farms scattered across the country or continent. It is assumed that when wind supply is low in some parts, it should be high at others. Hence, the wind farms with strong winds can share energy to the other places.
The capacity factors of wind farms range from 20-40%, with those found in highly-rated sites having capacity factors near the higher end of the range. Capacity factor refers to the ratio between the actual production for a given year to the ideal production of that area.
One problem with setting up wind farms in areas where wind energy supply is high (naturally, where wind velocities are high) is that they are far from densely populated areas, where the demand is expected to be high. Therefore the availability of transmission lines is one of the major factors considered when choosing an ideal site for a wind farm.
Wondering now how a wind turbine works or how wind power works? We’ve got answers to those questions right here on Universe Today.
At USGS there’s an article about wind power-related research projects at Patuxent Wildlife Research Center and how wind energy can be friendly to wildlife.
Here are two episodes at Astronomy Cast that you might want to check out as well:
Galileoscope, Black Hole Time, and What Exactly is Energy?
A Universe of Dark Energy
Sources:
http://en.wikipedia.org/wiki/Wind_power
http://www.eia.gov/kids/energy.cfm?page=wind_home-basics-k.cfm
http://www.energyquest.ca.gov/story/chapter16.html
http://www.nrel.gov/learning/re_wind.html
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