(Published, 03/01/2020, Ruralite)
Operation & Design
As wind blows across propeller blades, it pushes them causing a turbine to spin. That spinning action generates electricity. Most wind turbines are built onto masts of 280-330 feet tall. This height puts the propeller blades in optimal position to take advantage of greater wind speeds. The blades themselves average 120 feet in length.
Wind is a renewable resource. It is created as air naturally moves from areas of high pressure to areas of low pressure. Generally, this is caused by the uneven heating of the Earth’s surface by the Sun.
Emissions and Environmental Impact
Wind turbines do not produce any emissions. They have been known to endanger flying birds and bats. The whirring blades produce some noise as well that may affect people and wildlife. Although, these same criticisms could be said for highways, skyscrapers or industrial sites.
Operating and Maintenance Costs
Wind turbines obviously don’t require fuel so they cost very little to operate. As with anything, maintenance costs increase as they age. Modern wind turbines are still a relatively new technology. Some estimates suggest they can operate for over 30 years, though there are many deployed turbines that lasted less than 20 years. Turbines can be repaired and most of the metal structure can be recycled but the fiberglass blades deteriorate over time and must be placed in landfills. Efforts are being made to find ways to recycle the material used in the blades.
Most wind turbines are placed in flat, grassy, rural areas. Some locations are better than others. It is more economical to place wind turbines near existing electrical infrastructure. Wind turbines can also be located offshore, distributed throughout a grid or even built completely off-grid.
Wind is unpredictable and intermittent. In order to generate electricity, turbines require a minimum wind speed of about 6-9 miles per hour (this is known as the cut-in speed). The optimum range for wind speed is around 20 miles per hour and the maximum safe speed is about 45 mph (cut-out speed).
Consumers want electricity to be available at any time. So, utilities seek ‘firm’ sources of generation that can be ramped up or down to meet demand. Wind is a non-firm resource (wind cannot be made on demand) so it only works when tied to another system to fill in when wind generation can’t meet consumer demand.
- The output of a wind turbine depends on the turbine’s size and the wind’s speed through the rotor. An average onshore wind turbine has a capacity of 2–3 Megawatts
- Modern wind turbines are nearly 300 feet tall - about the same height as the Statue of Liberty