Are Wind Turbines Built In The Us?

Wind turbines are devices that convert kinetic energy from the wind into electrical energy. The wind turns the blades of the turbine, which spin a shaft connected to a generator that produces electricity. Wind turbines provide a clean and renewable source of energy. According to the U.S. Department of Energy, wind power is one of the fastest growing energy sources in the United States and accounted for over 8% of total U.S. electrical generation in 2019.

The development of wind power in the United States began in earnest in the 1970s as a response to the oil crisis. Advancements in wind turbine technology, government subsidies, and state renewable portfolio standards have helped drive substantial growth over the past two decades. As of 2020, the United States had over 122,000 wind turbines across 41 states and two U.S. territories, with over 120,000 megawatts of installed wind power capacity. Texas leads the nation in both wind power capacity and generation, followed by Iowa, Oklahoma, Kansas, and California. Offshore wind farms along U.S. coastlines are also starting to come online and represent a major expansion opportunity for wind energy.

History of Wind Power

Wind power has been utilized for centuries, with some of the earliest windmills dating back to Persia in the 7th century. The Dutch substantially advanced windmill technology in the 17th century, using windmills to drain lakes and marshes. Windmills were an essential technology, used for pumping water and grinding grain for hundreds of years.

The first windmills capable of generating electricity appeared in the late 19th century. In 1888, Charles Brush built the first wind turbine in Cleveland, Ohio that powered his home’s lights. Throughout the early 1900s, small wind turbines generating direct current provided electricity to farms and ranches in rural areas without access to an electric grid.

The growth of the commercial wind power industry began in the 1970s, spurred by the oil crisis and a push for clean energy. The first large-scale wind farms were built in California, and the industry saw rapid expansion. Technological improvements led to increased turbine sizes and efficiency. By 2014, wind power surpassed hydroelectric as the top source of renewable electricity generation in the United States.

Sources:
History of Wind Power in the United States
Wind Energy in America
The Evolution of Wind Power

Wind Turbine Locations

The majority of wind turbines in the United States are located in the central plains, specifically Texas, Oklahoma, Kansas, and Iowa, where wind resources are abundant. According to the U.S. Geological Survey, over 59,000 wind turbines were operating in the U.S. as of December 31, 2021, with many concentrated in the Central Plains states. Texas has the highest number of utility-scale wind turbines at over 14,000 ¹.

Wind power capacity is also growing off the Atlantic coast and in the waters of the Great Lakes. Offshore wind farms currently operating in the U.S. are located off the coasts of Rhode Island, Virginia, and North Carolina. Many more offshore projects are planned along the East Coast in the coming years as the offshore wind industry expands in the U.S. ². While most of America’s wind power is generated on land, offshore wind capacity is expected to grow rapidly and make up a larger share of total wind energy.

Major Wind Turbine Manufacturers

The majority of wind turbines installed in the United States are produced by foreign manufacturers. The top wind turbine companies supplying the US market include Vestas (Denmark), Siemens Gamesa (Germany/Spain), and Goldwind (China). However, some major domestic wind turbine manufacturers also have a strong presence, such as GE Renewable Energy.

General Electric (GE) historically was one of the top suppliers of wind turbines in the US through its wind energy division. Although GE has now sold off this business, its turbines still account for over 20,000 megawatts of wind capacity across 41 states. Other key domestic manufacturers include Nordex USA and Senvion.

The growth of wind power in the US has allowed domestic production of wind turbine components to increase in recent years. But foreign companies still dominate wind turbine manufacturing and install the majority of utility-scale wind projects in the country.

Turbine Components

Wind turbines consist of many components, but the key components include:

• Tower – The tower supports the rotor and nacelle and is typically made of tubular steel, concrete, or steel lattice. Towers range from about 65-100 meters tall (https://www.airpes.com/wind-turbine-parts/)
• Rotor blades – Most turbines have three rotor blades made of fiberglass or carbon fiber. The rotor diameter can be over 100 meters across to capture more wind energy.
• Nacelle – The nacelle sits atop the tower and contains the gearbox, generator, controller, and brake. It allows the rotor to face into the wind.
• Gearbox – The gearbox increases the rotational speed to the level required by the generator. Many newer turbines utilize direct-drive generators without gearboxes.
• Generator – The generator uses magnetic fields to convert the rotational energy into electrical energy. Generators may be asynchronous or synchronous.
• Yaw drive – The yaw drive rotates the nacelle and rotor to face into the wind.

Other components include the wind vane, anemometer, brake, transformers, cables, and more. The design of wind turbines can vary, but these are the key components that make up a wind turbine system.

Turbine Sizes

The size of wind turbines has increased dramatically over the past few decades. In the 1980s, small turbines were typically in the 25-100 kW range. By the 2000s, 1.5-2.5 MW turbines became more common. Today, some of the largest wind turbines are in the range of 3-5 MW.

According to the U.S. Energy Information Administration, the average height of wind turbines installed in the U.S. since 2012 is around 280 feet or 80 meters. This is a significant increase from turbine heights before 2006 which were typically less than 200 feet (Source).

The largest wind turbine in operation today is the GE Haliade-X offshore turbine which has a capacity of 12 MW and stands 853 feet (260 meters) tall. The blades on this massive turbine are 351 feet (107 meters) long (Source).

In general, taller towers with longer blades can capture stronger winds and generate more power. So there is a trend toward ever-increasing wind turbine sizes to maximize energy production.

Wind Turbine Efficiency

The efficiency of wind turbines describes how much of the kinetic energy in wind is converted into electricity. This is measured by a turbine’s capacity factor.

Capacity factor is the ratio of a wind turbine’s actual power output over a period of time compared to its potential output if it was operating at full capacity the entire time. The capacity factor of wind turbines has improved dramatically over the past few decades.

In the 1980s, wind turbines typically had capacity factors of 20-30%. By 2000, capacity factors reached 30-35%. Today’s state-of-the-art turbines have capacity factors of 50% or higher.

Higher capacity factors translate into greater electricity generation and lower costs per kWh. Improvements in turbine design, taller towers, longer blades, advanced controls, and site optimization have all contributed to substantially higher efficiency over time.

Going forward, capacity factors are expected to continue improving as wind turbine technology evolves. This will make wind power increasingly cost competitive with conventional power sources.

Cost of Wind Power

The installed cost per wind turbine has declined substantially over the past few decades. According to a 2021 report from the Lawrence Berkeley National Laboratory, the average installed cost for wind projects in 2019 was $1,526/kW, down from over $6,000/kW in the early 1980s (adjusted for inflation) [1]. This cost reduction is attributed to larger turbines, manufacturing improvements, and increased competition among suppliers.

When considering the ongoing costs of wind energy, experts often use “levelized cost of energy” (LCOE) for comparison. LCOE factors in capital costs, operations and maintenance, financing costs, and expected output over the turbine’s lifetime. Multiple studies show that the LCOE of wind energy is competitive with conventional sources like coal and natural gas. A 2016 report found the unsubsidized LCOE for wind ranging from $32-$62/MWh, while coal was $60-$143/MWh [2]. With wind’s minimal fuel costs, LCOE is relatively stable compared to fossil fuels that experience price volatility. So wind energy offers a consistent, affordable source of power generation.

Environmental Impact

The environmental impact of wind turbines is complex and debated. On one hand, wind energy generates electricity without emitting greenhouse gases or other air pollutants. According to the US Department of Energy, wind turbines in the US avoided an estimated 202 million metric tons of CO2 emissions in 2020 alone (https://www.energy.gov/eere/wind/environment). This is a major environmental benefit compared to fossil fuel power plants.

However, there are some concerns around wind turbines’ impact on wildlife. Wind turbines can pose a collision risk for birds and bats. One study estimated wind turbines cause between 214,000 and 368,000 bird deaths annually in the US (https://tethys.pnnl.gov/sites/default/files/publications/Verma-et-al-2022.pdf). Though this represents a small fraction compared to other human-caused sources of bird mortality, it’s an ongoing issue wind developers aim to mitigate through improved turbine design and siting.

There are also concerns around wind farms’ impact on bat populations. Bats are prone to injury from changes in air pressure near spinning turbine blades. Strategic operation of wind turbines during bat migration seasons and placement away from known bat habitats can help reduce bat fatalities.

While wind power has advantages over fossil fuels, responsible siting, operation, and mitigation practices remain important to limit its ecological footprint.

Future of Wind Power

The future of wind power in the United States looks promising, with projections for significant growth in capacity over the next decade. According to the U.S. Department of Energy’s Wind Vision report, wind power capacity could reach 10% of U.S. electricity demand by 2020, 20% by 2030, and 35% by 2050. The DOE analysis shows wind power capacity growing from 61 GW in 2013 to 110 GW in 2020 and 404 GW in 2050 under the Wind Vision study scenario.

New wind turbine technologies on the horizon are expected to contribute to this growth. Larger rotors, taller towers, improved controls, and other innovations will allow turbines to capture more energy at lower wind speeds. Offshore wind farms in U.S. waters also have significant potential, with the first commercial projects coming online in the next few years. Floating offshore platforms could unlock even more offshore wind capacity. Continued cost reductions through technology advances, manufacturing improvements, and economies of scale will further boost wind power expansion in the years ahead.