Wind Turbines and Power
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Wind turbines are the opposite of fans; fans use electricity to make wind and turbines use wind to make electricity. Wind is caused by three things; the sun unevenly heating the atmosphere, irregularities of the earth's surface, and the rotation of the earth. The process of using wind to create mechanical energy or electricity is called either “wind energy” or “wind power.” When wind turbines turn wind power to electricity, they rely on the aerodynamic blades that work in ways similar to airplane wings and helicopter blades. As the wind blows across the blade, the air pressure on one side decreases, causing lift and drag. The drag force is weaker than the lift force, and this causes the blades to spin and the generator to make electricity. Horizontal wind turbines usually operate upwind (or facing the wind) and often have three blades. Vertical axis wind turbines are omnidirectional (which means they do not have to turn to face wind) and come in many shapes. Distributed wind is any wind turbine that is “installed on the customer side of the electrical meter” or is close to where the power it makes will be used. Most are small (under 100 kilowatts) and typically used in residential or agricultural applications. Small wind turbines can be used with another power source and are then called hybrid wind systems; these are regularly located off-grid, but are becoming more common within electrical grids for more resiliency (Wind Energy Technologies Office).
This show three types of wind turbines and how they move. From left to right, a Savounius Verticle-Axis model, a Horizontal-Axis model, and a Darrieus Verticle-Axis model.
Since 2000 wind power capacity in the United States has more than increased 24-fold (info from 2014). Wind turbines are 100 feet or taller, usually with three blades, but sometimes two. Low-pressure air pockets are formed when the wind blows, and this causes the wind turbine’s blades to spin. Gears inside the turbine increase the number of revolutions per minute and turn the revolutions into AC energy. There are two main types of wind turbines, vertical and horizontal, horizontal being the most common. Offshore turbines provide a lot of energy because of constant and strong offshore winds, but these turbines are a lot more expensive because of the distance from cities to coasts. The U.S. Department of Energy has “helped to increase the average capacity factor (a measure of power plant productivity) from 22% for wind turbines installed before 1998 to more than 32% for turbines installed between 2006 and 2012,” says the U.S. Department of Energy. Since 1980, the cost of a kilowatt-hour of power from a turbine has been reduced from 55 cents to under 6 cents in 2014 (“How a Wind”).
More information from the US Department of Energy.
Before the end of 2020, 132 wind turbines would tower over a dry plateau in Wyoming, on a breezy day these turbines could power a medium-sized city. Wyoming was “built on coal,” says Dave Freshnour, and it’s true; Wyoming produces 40% of the United States coal, and also produces large amounts of oil and natural gas. But the “Energy State” is also a good place to produce both wind and solar-based energy. Laine Anderson, the operations director at PacifiCorp, says, “If Wyoming had the transmission lines, and they would let us, I'm sure this whole area would be covered with turbines.” In 2010, renewable resources were only 10% of the electricity supply, but since then “the national chart of electric power sources looks like an “X,” with renewables and natural gas the rising leg and coal the falling one.” In 2020, the lines crossed. Part of this is the cost of solar panels has dropped 65% in a decade and the efficiency has drastically increased from 6% to 30% from when the first panels were invented (as of 2020). But wind turbines face a big obstacle: lack of transmission lines in Wyoming, wind power “flourished” in 2005, but slowed down because transmission lines were expensive and unrealistic. Still, Anderson says “we're changing our portfolio drastically” to embrace wind and shows the foundation for a new wind turbine; nearly 2 million pounds of concrete (Struck).
The percentage of energy that comes from wind and solar in the U.S. has nearly quadrupled since 2011 with an annual increase of almost 15% (as of 2021), says the Environmental America Research and Policy Center. This study also found that if these rates keep up, wind solar, and geothermal power would meet the current electricity demands by 2035; the same year President Biden aims to have a completely fossil-fuel-free electricity grid. In 2011 there were 125,802 kilowatt-hours of power produced by wind and solar, whereas in 2021 470,141 kilowatt-hours were produced. Iowa, along with Kansas and North Dakota, now produce at least half of their energy needs from solar and wind. From 2011 to 2018 the cost of utility-scale solar dropped 80% and continues to decline. California is a state that “has enacted really aggressive policies” supporting renewable resources. It is not a coincidence that California is by far the national leader in solar-powered energy production. The report says, “every state in the country has enough potential from either solar or wind energy alone to supply all of its electricity needs.” But the U.S. still has work to do, only 12% of the energy we produced is renewable, putting us in “the middle of the pack” globally. Germany and the U.K. make more than double the amount the U.S. does (Root).
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