Wind is a form of solar energy, caused by the sun’s unevenly heating of the atmosphere, irregularities in the earth’s surface, and the earth’s rotation. Wind flow patterns and speed vary by regions and are modified by bodies of water, vegetation and terrain. The terms “wind energy” and “wind power” both describe the process by which the wind is used to generate mechanical power or electricity. This mechanical power can be used for specific tasks (such as grinding grain or pumping water) or a generator can convert this mechanical power into electricity. A wind turbine turns wind energy into electricity using the aerodynamic force from the rotor blades. When wind flows across the blade, the air pressure on one side of the blade decreases. The difference in air pressure across the two sides of the blade creates both lift and drag. The force of the lift is stronger than the drag and this causes the rotor to spin. The rotor connects to the generator, either directly (if it’s a direct drive turbine) or through a shaft and a series of gears (a gearbox) that speed up the rotation and allow for a physically smaller generator. This translation of aerodynamic force to the rotation of a generator creates electricity.

Production and Economy

The United States has been actively developing wind energy in the past decade, accounting for a large share of its electricity supply in some states, but currently this industry still relies on massive government subsidies.

In 2020, the United States onshore wind capacity has grown to 122 GW. In 2008, installed capacity in the U.S. increased by 50% over the prior year. The world average growth rate that year was 28.8%. In 2019, electric power generation from wind power was 10 percent or more in fourteen U.S. states: Colorado, Idaho, Iowa, Kansas, Maine, Minnesota, North Dakota, Oklahoma, Oregon, South Dakota, Vermont, Nebraska, New Mexico, and Texas. Iowa, South Dakota, North Dakota, Oklahoma, and Kansas each had more than 20 percent of their electric power generation come from wind. Twenty states now have more than five percent of their generation coming from wind. Iowa became the first state in the nation to generate 50% of its electricity from wind power in 2020, as predicted in 2015. The 2020 report on energy costs by Lazard found that the unsubsidized levelized cost of energy (LCOE) for onshore wind is 2.6 to 5.4 cents per kilowatt-hour (kWh), and the median unsubsidized LCOE for offshore wind is 8.6 cents per kWh. In comparison, the lowest-cost conventional source, Gas Combined Cycle, has a cost range of 4.4 to 7.3 cents per kwh. Subsidies such as the investment tax credit and production tax credit further reduce the current cost of wind energy, which is scheduled to decline and expire in the coming years.

Types of Wind Turbines

The majority of wind turbines fall into two basic types:

Vertical-Axis Turbines: Horizontal-axis wind turbines are what many people picture when thinking of wind turbines. Most commonly, they have three blades and operate “upwind,” with the turbine pivoting at the top of the tower so the blades face into the wind.

Vertical-Axis Turbines: Vertical-axis wind turbines come in several varieties, including the eggbeater-style Darrieus model, named after its French inventor. These turbines are omnidirectional, meaning they don’t need to be adjusted to point into the wind to operate.

Applications of Wind Turbines

Modern wind turbines can be categorized by where they are installed and how they are connected to the grid.

Land-based wind turbines: Land-based wind turbines range in size from 100 kilowatts to as large as several megawatts. Larger wind turbines are more cost-effective and are grouped together into wind plants, which provide bulk power to the electrical grid.

Offshore wind turbines: Offshore wind turbines tend to be massive, and taller than the Statue of Liberty. They do not have the same transportation challenges as land-based wind installations, as the large components can be transported on ships instead of on roads. These turbines are able to capture powerful ocean winds and generate vast amounts of energy.

Distributed Wind turbines: When wind turbines of any size are installed on the “customer” side of the electric meter or are installed at or near the place where the energy they produce will be used, they’re called “distributed wind. Many turbines used in distributed applications are small wind turbines. Single small wind turbines—below 100 kilowatts—are typically used for residential, agricultural, and small commercial and industrial applications. Small turbines can be used in hybrid energy systems with other distributed energy resources, such as microgrids powered by diesel generators, batteries, and photovoltaics. These systems are called hybrid wind systems and are typically used in remote, off-grid locations (where a connection to the utility grid is not available) and are becoming more common in grid-connected applications for resiliency.

Advantages and Disadvantages

Wind energy is sustainable and clean. The nation’s wind supply is abundant and inexhaustible. Over the past 10 years, U.S. wind power capacity has grown 15% per year, and wind is now the largest source of renewable power in the U.S. The development of wind turbines is a powerful response to climate change and air pollution as it does not produce atmospheric emissions.

Economically, wind turbines cut both ways. Its upfront costs are quite high, especially for offshore wind turbines. The installation involves a rigorous survey. After finding an ideal place, the cost of transportation and installation is also high. On the other hand, the land-based utility-scale wind is one of the lowest-priced energy sources available today, costing 1–2 cents per kilowatt-hour after the production tax credit.

Wind turbines are not pleasant objects in some cases. Turbines might cause noise and aesthetic pollution. The impact the natural beauty of the landscape. When a lot more wind turbines are set up, the area becomes unsightly. The sound produced by one turbine can be perceived from far distances. Wind turbines are also a threat to bird populations, with large numbers dying on collision.

Future Outlook

In order to meet the challenge of climate change, the future development of wind turbines is expected to receive significant financial and policy support, and the cost is expected to continue to fall, making it a rewarding investment.

The Wind Vision Report makes a number of predictions for wind power by 2050 in the U.S:

• Wind can be a viable source of renewable electricity in all 50 states by 2050.
• Wind energy supports a strong domestic supply chain. It has the potential to support over 600,000 jobs in manufacturing, installation, maintenance, and supporting services.
•  By 2050, wind energy could avoid the emission of 12.3 gigatonnes of greenhouse gases.
• Wind energy preserves water resources. By 2050, wind energy can save 260 billion gallons of water that would have been used by the electric power sector.
• Wind energy deployment increases community revenues. Local communities will be able to collect additional tax revenue from land lease payments and property taxes, reaching $3.2 billion annually by 2050.