Keep in mind that sometimes the wind blows slowly or not at all, and windmills don't produce any power until the wind reaches about 8 MPH. A location for a windmill is not considered viable unless wind speeds average 14 MPH.
The percentage of its rated power that a windmill can actually produce, given the variation of wind speeds at the installation site, is called its capacity factor. A realistic capacity factor is 25%. That means that over time, the windmill actually delivers 25% of its rated power.
(Electrical energy is measured in units called watts. A kilowatt (KW) is 1,000 watts, a megawatt (MW) is a million watts. )
A typical large wind-driven turbine is rated at about 1,500 kilowatts. It's 350 feet tall and has a fan blade of about 240 feet in diameter. It will actually deliver about 375 kilowatts. It can power about 375 microwave ovens, or 6250 60-watt light bulbs simultaneously (only when the wind is blowing at about 25 miles per hour, which is a very strong wind). An average (1 gigawatt) power plant can power nearly a million microwaves, or 16 million light bulbs at the same time.
A power plant near me produces 1,100,000 kilowatts (1.1 gigawatts) of power. At a 25% capacity factor it would take nearly 2600 large wind turbines to produce the same power as this nuclear power plant. And this is not a particularly large plant.
If you placed these 2600 wind turbines the recommended 5 rotor-blade diameters apart, they would stretch for 600 miles. That's as far as the distance from Michigan to Georgia. In practice wind turbines are not placed single file, they are placed in several rows, like crops, in what are called wind farms, but you get the idea.
The amount of electricity generated by a wind turbine is proportional to the wind speed to the 3rd power (a 20 MPH wind will produce 8 times as much energy as a 10 MPH wind). Therefore wind turbines often produce energy in bursts; when the wind gusts, the energy output spikes, when the wind dies down, energy output dips.
Unfortunately, there is no easy way to store these bursts of energy for later use. There are no batteries large enough that are also practical, and pumped-storage systems, which use unwanted energy to pump water into an aboveground reservoir for later use in turning a water-driven generator, require a large body of water.
And when there is no wind, windmills produce no power, so a traditional power plant must be operational at all times to provide power during those in-between times.
Thanks for that post. It still amazes me that people are daft enough to fall for this scam.
GREAT POST!
Well that’s easy to fix. Just install electric motors to spin the blades when there is no wind.