Wind energy is playing a crucial role in the reduction of greenhouse gas emissions globally. Since the burning of fossil fuel got rolling at the start of the Industrial Revolution, carbon dioxide in the atmosphere has substantially increased. As the ice sheets continue their existing patterns of melting due to elevating temperatures, the sea level will also continue to rise over the next century, and beyond. A direct consequence of trapped CO2 in the atmosphere, melting polar ice caps will bring large-scale coastal flooding. The result will be that our pattern of life on earth will be changed forever. But wind energy is one way in which we can lessen anthropogenic climate change and attempt to remedy a legacy of environmental degradation.
Wind is an energy source that is a viable and clean alternative to fossil fuels, and the worldwide installed capacity of wind power has many economic and environmental advantages.
It’s time that more of us learn more about wind as an important energy resource. What are wind energy, wind power, and wind turbines all about, anyway?
What is Wind Energy?
“Wind” is a movement of air from high-pressure areas to low-pressure areas. Caused by uneven heating of the earth’s surface by the sun, wind results when hot air rises up and cool air flows in to replace it. The sun and winds work reciprocally: as long as solar energy exists, winds will occur.
Wind power consists of turning energy from the wind to other energy forms. Two important properties of wind to consider when discussing energy source conversion are the airstream and the air density. In an idealized model of airflow, the wind velocity at the rotor of a turbine is the average of the upstream and downstream steady wind velocities. Wind turbines rely only on the first couple hundred feet of atmosphere, with a clear and steady air upstream velocity as optimal. Air density changes depending on altitude and atmospheric conditions such as temperature, pressure, and humidity.
Because wind is continual, it does not get depleted; therefore, wind is clean, safe, renewable, and an excellent source of energy. And, unlike many other sources of energy, wind power does not use any water. By 2030, it’s projected wind power will save around 30 trillion bottles of water in the US.
What were the Earliest Efforts to Harness Wind for Energy?
Wind power turns the energy that the wind creates into other forms of energy that are useful for humans.
Early mastery of the sea through wind and sail was imperative for colonialism, protection, and trade. Wind energy provided the power to move ships for thousands of years until the age of steam. The intermittent nature of powered vessels and the relative slowness of wind-powered vessels led to their reduction in use as a transportation method.
The earliest windmills can be traced to Afghanistan, China, India, and Persia 200 BCE, when farmers used wind power to pump water and to grind grains. These very early windmills had vertical axis. Later, thousands of windmills in medieval Europe transformed industry and society radically as part of an industrial revolution entirely powered by renewable energy. Around 1600, many new industrial applications of windmills appeared in the shape of saw mills, paper mills, mustard mills, and tobacco mills. Eventually, windmill blades captured the wind’s mechanical energy, and then small turbines charged batteries or were applied as backup power in caravans and sailing ships.
Vermont was home to the first modern US wind turbine in the 1940s. Today, wind energy is converted to electrical energy across many sites in the US to meet the nation’s critical energy needs.
How do Wind Turbines Generate Electricity?
Contemporary wind turbines have two designs: horizontal-axis and vertical-axis design. The eggbeater-style Darrieus model is named after its French inventor.
Today’s horizontal-axis wind turbines usually have three blades. These three-bladed wind turbines are operated “upwind,” with the blades facing into the wind. To some people, the blades of a wind turbine look like enormous propellers on a plane. The energy in the wind turns these propeller-like blades around a rotor that is connected to the main shaft. The blades are spun by the wind, which transfers motion to a shaft. That shaft spins a generator to create electricity.
Watch this video to learn more about how wind turbines work:
Wind turbines can be built on land or offshore in large bodies of water like oceans and lakes. Utility-scale turbines often are situated offshore. They are larger, can generate more power, and do not have the same transportation challenges of land-based wind installations, as the large components can be transported on ships instead of roads.
The tips of the largest wind turbine blades can reach heights up to 200 m (650 ft). Speed at the tip can reach over 320 km/h (200 mph). A wind turbine has as many as 8,000 different components. According to Ledo, et al, the important factors which affect the performance of turbines are low mean wind speeds, high turbulence, and high aerodynamic noise levels generated by the turbines.
Small-Scale vs. Large-Scale Wind Generation
Properly sized small-scale wind turbines can be used as reliable sources of energy when harnessed at optimum conditions. A small turbine in a yard can power a small business or a home in certain situations. In locations which are far away from the grid, these small-scale turbines can act as a useful power source.
When compared to large-scale wind turbines, small-scale wind turbines are those which have their rotor diameter ranging from 3m to 10m and have a power capacity of 1.4–20 kW. Single small turbines, below 100 kilowatts, are typical applications for homes, telecommunication dishes, or water pumping. Small turbines are sometimes used in connection with diesel generators, batteries, and photovoltaic systems.
A typical large-scale wind turbine has a rotor diameter ranging from 50 m to 100 m. It produces power between 1 and 3 MW. Many larger-scale wind turbines are grouped together in wind farms to form a wind plant for utility-scale sources of wind energy.
Large Wind Farms
Large groups of wind turbines are called wind farms. The wind turbines are often arranged in lines in windy spots like a ridge. When multiple wind turbines are situated in the same location, large amounts of electric power — comparable to a coal or nuclear power plant — can be generated.
Large onshore wind farms are located all over the world now, with many of the largest ones located in the United States. Large offshore wind farms have been growing in global power market share at a fast rate as well, but much more so in Europe than other places.
The first American offshore wind farm began operating in late 2016 off the coast of Rhode Island, delivering power to the community on Block Island. More offshore wind projects are anticipated in the near future, bringing with them the promise of new jobs and low-cost, carbon-free energy.
Deepwater Wind, the primary offshore US wind developer in the United States, is pursuing development of a 144 MW offshore wind farm near Martha’s Vineyard that will be equipped with a 40 MWh Tesla battery storage system.
A large-scale UK wind farm project underway 42 miles off the coast of Norfolk is already offering a low price of just £119 MWh — “more than 15% lower than other offshore wind farms under construction in the UK” and putting it in the range of the lowest cost options for new power capacity in the region. The wind farm “will deliver power to the equivalent of 500,000 households in Suffolk and Norfolk.” The project could grow to power nearly a million homes by 2025.
Wind turbines can be installed offshore on floating structures, sending the electricity generated back to land with the help of undersea cables.
What are the Benefits of Wind Turbines & Wind Energy?
Technological innovations and the capacity for wind turbine mass production have lowered the cost of wind power considerably year to year. Wind costs follow what economists call a learning curve — for every doubling of wind production, the cost goes down by a fixed percentage. And the costs to operate wind turbines once they’re up and running are modest. As a whole, we must look at the total cost to create wind power and get that electricity to homes. As it turns out, in many if not most regions (like the United States), onshore wind power is the cheapest option for new power generation.
Wind energy ventures have been receiving subsidies from governments in recent years to stimulate technology adoption and improvements to efficiency and cost. The justification for subsidizing a given technology like wind turbines is that it delivers public benefits that outweigh the subsidy cost. Additionally, every major form of power generation has received massive government subsidies to get to a mature level — and, actually, they all still do. Wind seems to be paying off for the good of society and market prices have rapidly dropped to competitive levels.
The latest annual report from the Global Wind Energy Council revealed that more than 54 gigawatts of new wind power were installed during 2016, and the technology is now competing with “heavily subsidized incumbents across the globe.”
If you take into account health savings, climate protection savings, and other environmental benefits, wind power looks even better — it actually has a lighter footprint than even solar power.
Importantly, 1 megawatt (MW) of wind power can offset approximately 2,600 tons of carbon dioxide (CO2) annually.
The US Department of Energy offers 10 wind energy benefits that are a must know:
- Wind energy is cost competitive with other fuel sources.
- Wind energy creates jobs.
- Wind energy is an indigenous, homegrown energy source that helps to diversify the national energy portfolio.
- Wind energy can provide income for farmers and ranchers, as well as economic benefits to communities.
- Wind energy is an inexhaustible renewable energy source.
- Wind turbines do not consume water.
- Wind energy is clean.
- Wind energy systems have low operating costs.
- Wind energy can be used in a variety of applications.
- Wind energy is deployed in all US regions and is widely supported.
What are Some Concerns about Wind Turbines?
Wind turbines do not produce any pollutants or emissions during operation that could harm the environment, except those required for maintenance (which are minimal). The major drawbacks of wind energy are high upfront costs, variability in wind speeds, and unsuitability in regions that do not have constant winds. Rick Perry and the Department of Energy sought to determine in a grid reliability report whether wind and other renewable energy sources cause reliability problems because they don’t supply power continually — the answer was that this was not a notable problem.
Some say that the noise produced by wind turbines disturbs neighborhood residents, but no thorough scientific research has found this to be true.
Sometimes birds and bats succumb when they come in contact with the turbine’s blades. Sad as this is, birds and bats also die when they come in contact with motor vehicles, power lines, high-rise buildings, and planes. In fact, more birds die from nuclear, coal, and natural gas power plants than wind farms per kWh of electricity produced.
Another criticism is that wind energy is variable — if there is no wind due to some reason, the generation of electricity stops. However, numerous studies and articles have explained why this is not particularly important.
The large blades of wind turbines can interfere with some radar systems used by weather stations or air traffic controls, at times being mistaken for planes or various weather patterns. This limits where wind farms can be located.
The Future Prospects for Wind Energy
There are high hopes for wind as a renewable energy source to help society maintain a stable climate, better energy security, and less pollution. Wind turbines are getting taller, more efficient, and more powerful. The American Wind Energy Association announced that the US wind energy industry added jobs at more than 9 times faster than the overall US economy in 2016, reaching 102,500 jobs. It helped to install over 8 gigawatts of new wind power, with investments reaching more than $14 billion.
Iowa is on course to be the first US state to hit 40% of its electricity from wind generation with the completion of Des Moines–based MidAmerican Energy Co’s $3.6 billion Wind XI project, which will add up to 2,000 MW of new wind electric generation in the state, and additional projects announced earlier this year.
Germany, Denmark, and Belgium have an agreement that will increase the amount of offshore wind power 5-fold, from 13.8 gigawatts today to more than 60 gigawatts within 10 years.
Wind energy should be able to meet one-third of global energy demands by 2050 if it continues on the current pace of progress and innovation. Clean energy tax credits and other subsidies will be of help in achieving this target.
If you’re still uncertain about the place and permanence of wind power, check out this interactive tool that shows the evolution of wind power around the world. You’ll become convinced that wind energy resources are here to stay.