Harvesting the energy of the wind is certainly not a new concept. Wind power has been filling our sails and turning our windmills for thousands of years. So, it is not surprising that in our search for alternative energy sources, wind energy has emerged as a major player. Wind turbines dot the horizon throughout the US, sometimes meeting with some controversy. So, if you haven’t made up your mind about the giant propellers, read on for some important wind power facts.
First, a lesson on hot air. Wind is the movement of air from an area of high pressure to an area of low pressure. Some locations are consistently windy and this is because the sun warms one area faster (creating a low pressure area) than a nearby area (high pressure area), creating a constant movement of air.
For example, coastlines are notoriously windy areas because the sun warms the ground faster than it warms the ocean. The air above the ground heats up and rises creating a low pressure area. The cooler air above the ocean then flows in to fill this gap.
Wind farms are ideally situated in areas such as this; a good steady wind, not necessarily strong, but consistent.
Facts about the turbines themselves
Fact#1: Wind turbines convert mechanical energy into electrical energy; the wind spins the turbine blades, which turns a shaft connected to a generator.
Fact#2: Turbine towers are steel and hollow and range in height from 82 to 262 feet. The blades are made of glass-fibre reinforced polyester or wood epoxy and can reach a diameter of up to 213 feet. They are almost exclusively light grey in colour to make them as inconspicuous as possible against the skyline.
Fact#3: There is no air or water pollution associated with wind turbines.
Fact#4: Turbines typically last 20 to 25 years and as they have moving parts, some components may need repair or replacement during that lifetime. However, operational costs are virtually nothing once the turbine is installed.
Fact#5: Most turbines start turning at wind speeds of 10 mph and reach a maximum power output at wind speeds of around 33 mph. They are programmed to shut down at winds greater than 50 mph (gale force).
Fact#6: Turbines produce electricity 70-85% of the time. This means that a 1.8MW wind turbine in the right place can produce enough electricity to meet the annual needs of over 1,000 households.
Fact#7: Turbine technology has improved in recent decades to reduce noise pollution. These days, the noisiest aspect of a wind turbine is the ‘swoosh’ sound made as the rotor blade passes the tower. It is possible to hold a conversation beneath a wind turbine without having to raise your voice.
Fact#8: If the wind is not blowing, no electricity is produced. So, just as with harnessing solar energy, a back-up system is required. That can be as easy as drawing from a grid when the turbine is not producing, or batteries for short-term storage, or back-up sources such as solar, or generators depending on your circumstances. Also, as with solar power, wind power can feed into the grid when more energy is produced than is being drawn.
Facts about wind farms
Fact#9: If a wind farm is located in an area with a good consistent wind, it only takes 3-8 months for it to generate more energy than was originally used in its building and installation. This makes it one of the fastest “energy payback times” of any energy technology.
Fact#10: You can fit 20 wind turbines into less than half a square mile. Only 1% of that area is taken up as part of the infrastructure footprint (i.e. the base of the turbine, roads, etc), which leaves a large portion of the land useable for other activities such as grazing animals.
Fact#11: Wind farms are a good fit for many struggling farmers. A land lease on a 250 acre wind farm can generate $14,000/year but the infrastructure will only utilize 3 acres (source).
Fact#12: Offshore wind farms are well placed for catching consistent winds. They also move the turbines, which may consider unattractive, out of sight. However, offshore weather is unpredictable and at times hostile, which means offshore developments require more time to build, may require more maintenance, and definitely require more money. It also places the source of the energy further from the consumer.
Big picture facts
Fact#13: At the end of 2010, the total global installed wind energy capacity was 194.4 GW, and at that time the US was second to China with 40.1GW capacity (source). As of June 2011, the US has 42.4GW of wind capacity, which is more than 20% of the world`s wind power (source).
Fact#14: As of June 2011, the top 5 states for wind power are: Texas (10,135 MW), Iowa (3,675 MW), California (3,179 MW), Minnesota (2,432 MW), and Washington (2,356 MW) (source).
Fact#15: There is the potential to supply 20% of America’s electricity using wind power by 2030, which would reduce projected carbon dioxide emissions by 25% (source). A single 1.67MW turbine could reduce carbon dioxide emissions by over 3,000tons
Sadly, it is also a fact that wind turbines cause bird and bat deaths. With respect to birds, this must be put into perspective as deaths by turbines are minimal compared with deaths as a result of buildings, vehicles or domestic cats. In fact, in 2006, it was estimated that wind power was responsible for 3 out of every 100,000 bird deaths caused by humans and pets (source). However, there are large numbers of bat deaths associated with turbines and this is an area of current research.
Wind power facts speak for themselves. Wind provides an endless and clean power supply that can help reduce carbon emissions as well as our dependency on fossil fuels. As with other alternative energy sources, the costs of these clean energies decrease as demand increases and technologies improve, lowering economic hurdles. Turbine interaction with bats is clearly an issue that needs to be addressed, and conservation groups, industry, and government are working towards solutions. With these issues overcome, wind energy will hopefully continue to grow as an eco-friendly power source. In fact, you can view a map of planned and existing wind technologies throughout the US here. Suddenly, those towers don’t seem so unsightly! See the video below for more information.