Wind is an abundant and powerful natural resource that can act as a low carbon emissions source of energy. So, we had to ask: What is wind energy really, and how can it help to mitigate climate change?

Wind energy is the conversion of moving air into energy via wind turbines. Per KWh produced, onshore wind emits 11 and offshore wind emits 12 grams of CO₂ on a life-cycle basis. Wind energy helps combat climate change and has various additional environmental benefits.

Keep reading to find out all about what wind energy is, its global capacity, its carbon footprint, its environmental benefits and drawbacks, and how it can contribute to climate change.

The Big Picture of Wind Energy

Wind energy contributes to the avoidance of greenhouse gas (GHG) emissions from the burning of fossil fuels (e.g., coal, oil, natural gas). It is classified as a renewable energy source because the resource (wind) naturally replaces itself over time. 

How Is Wind Energy Defined

Wind energy is defined as the conversion of moving air into electrical energy through the use of wind turbines. 

“Wind: a current of air moving approximately horizontally, especially one strong enough to be felt”

Cambridge Dictionary

Wind is a form of solar energy that is caused by the uneven heating of the earth’s surface, irregularities of the earth’s surface, and the earth’s rotation. Wind patterns and speeds vary greatly across the world and can be modified by bodies of water, vegetation, and differences in terrain.

What Are the Different Types of Wind Energy 

There are two main types of wind energy:

1. Onshore wind energy: Wind turbines are located on land. Construction, transportation, maintenance cost, and infrastructure needed to transmit electricity from onshore turbines to consumers is low. 

The largest onshore wind farm in the world is the Gansu wind farm located in China. It consists of roughly 7,000 wind turbines across multiple wind farms Although it is still under construction, the planned capacity is 20 (gigawatts) GW, and the current installed capacity is 8 GW. 

2. Offshore wind energy: Wind turbines are located in the ocean or freshwater. Construction, transportation, maintenance cost, and infrastructure needed to transmit electricity from offshore turbines to consumers is high. Offshore turbines are considerably larger than onshore turbines and can cost up to 20% more, and noise pollution, land use, and wildlife impact concerns are minimal compared to onshore turbines. 

The largest offshore wind farm in the world is the Walney Extension wind farm located in the Irish Sea. Covering 56 square miles (149 square kilometers), the 87 wind turbines have an electricity generation potential of 659 megawatts (MW) of power. This is enough to power 600,000 homes in the United Kingdom. 

In short, onshore wind energy may be less efficient than offshore wind energy because onshore wind speed and direction can be unpredictable, whereas offshore wind speed and direction remain relatively fixed. However, the potential for offshore wind energy generation is much higher than onshore wind energy generation because wind speed and direction are more constant.

The two types of wind turbines are:

1. Horizontal axis wind turbine (HAWT): Blades are assembled on a horizontal axis parallel to the ground. They can only receive and process wind head-on. 

2. Vertical axis wind turbine (VAWT): Blades are assembled on a vertical axis perpendicular to the ground. They can receive and process wind from all directions, giving them a greater energy generation potential. 

And wind turbines can be divided into three categories based on how much power they are capable of generating:

1. Small (individual) turbines: Can produce up to 100 kilowatts (kW) of power, which is enough to power a home or a water pumping station. 

2. Large turbines: Consist of 260-foot (80 meter (m)) tall towers and 130-foot (40m) long blades that can generate up to 1.8 MW of power. 

3. Commercial turbines: Consist of 780-foot (240 m) tall towers and 530-foot (162 m) long blades that can generate anywhere from 4.8 to 9.5 MW of power. 

Wind energy encompasses a diverse range of materials, technologies, and environmental implications. So let’s have a closer look at these next.

How Does Wind Energy Work

To harness wind energy, the wind turns the turbine blades around a rotor, which spins a generator to create electricity. 

How Does Wind Energy Actually Produce Energy

Individual wind turbines use aerodynamic force from rotor blades to turn kinetic energy into electricity. Clusters of turbines (wind farms) work together to generate large quantities of electricity.

Wind energy operates in the following manner: 

• Wind flows across a turbine blade, creating a difference in air pressure across the two sides of the blade

• The blade spins in response, thereby spinning the rotor

• Spinning the rotor powers a generator which creates electricity

An average annual wind speed of 9 miles per hour (mph) or 4 meters per second (m/s) for small turbines and 13mph (5.8m/s) for utility-scale turbines is necessary to economically harness wind energy. 

What Is the Global Capacity of Wind Energy

Globally, wind energy is a fast-growing renewable energy source, accounting for roughly 23% of all renewable energy generation in 2021.

The scale of that energy generation varies significantly depending on the country. China, the United States, Germany, India, and Spain are the top wind energy-producing countries in the world, together accounting for over 537 GW.

The COVID-19 pandemic saw a decrease in fossil fuel emissions due to stay-at-home orders and supply chain disruptions. During this time, wind energy demonstrated year-over-year growth of 53%, adding more than 93 GW of power. Onshore wind added 86.9 GW, offshore wind added 6.1 GW, and global cumulative wind power capacity grew to 743 GW.

To meet the targets identified in the net zero by 2050 scenario, wind power generation must increase 18% per year during 2021-2030. We must also add 310 GW of capacity to onshore and 80 GW of capacity to offshore wind every year.

Because wind energy is one of the fastest-growing renewable energy technologies with a low carbon emissions profile, it is important to understand what its carbon footprint is and how its carbon emissions affect the global climate change process.

What Is the Carbon Footprint of Wind Energy

The carbon footprint is one of the ways we measure the effects of human-induced global climate change. It primarily focuses on the greenhouse gas (GHG) emissions associated with consumption and includes other emissions such as methane (CH₄), nitrous oxide, and chlorofluorocarbons (CFCs).

“Carbon footprint: the amount of greenhouse gasses and specifically carbon dioxide emitted by something (such as a person’s activities or a product’s manufacture and transport) during a given period”

Merriam Webster

Basically, it is the amount of carbon emitted by an activity or an organization. This includes GHG emissions from fuel that we burn directly (e.g., heating a home, driving a car) and GHG emissions from manufacturing the products that we use (e.g., power plants, factories, and landfills). 

On a life-cycle basis, onshore wind energy emits 11 grams and offshore wind energy emits 12 grams of CO₂ equivalent per kWh of electricity produced, the joint-lowest out of all fuel types. 

Have a look at the illustration below to see the average life-cycle CO₂ equivalent emissions of different energy sources and how they compare to wind energy.

When discussing the carbon footprint of wind energy, we must take into account carbon emissions across the energy’s building, operating, and building back phases.

Throughout its life cycle, wind energy produces 0.02% of the CO₂ emissions per unit of electricity than coal produces. And, after 3 to 6 months of operation, a wind turbine has effectively offset all emissions from its construction, which means it can operate virtually carbon-free for the rest of its lifetime. 

Wind turbines require routine maintenance every 6 months and have a life expectancy of around 20 years. Wind turbines themselves are a valuable source of resources. The towers, foundations, generators, and gearboxes are typically recycled because they are made of concrete, steel, and cast iron. Wind turbine blades are more difficult to dispose of because they are made of composite materials. Cement co-processing is most often used to treat blade waste. 

Because wind energy makes up an increasingly larger portion of renewable energy generation worldwide, it is important to understand what its carbon footprint is and how its carbon emissions affect the global climate change process.

How Environmentally Friendly Is Wind Energy

The environmental impacts of wind energy largely depend on where wind farms are constructed.

“Environmentally friendly: (of products) not harming the environment.”

Cambridge Dictionary

Overall, wind energy is sustainable because it does not emit greenhouse gasses, and land use, wildlife impact, and public health concerns can be mitigated by proper planning and siting of wind farms.

What Are Environmental Benefits of Wind Energy

Here are the ways in which wind energy benefits the environment:

• Protects air quality: Rather than combusting materials, wind turbines harness the kinetic energy of wind to generate electricity. Turbines do not produce greenhouse gasses and emit no sulfur dioxide or nitrogen oxides. 

• Few waste products: Wind farms do not create measurable solid waste byproducts. 

• Climate change mitigation: Wind energy has an average life-cycle CO₂ equivalent emission value that is much less than coal, 11g of CO₂ (onshore) and 12g of CO₂ (offshore) equivalent per kWh compared to 820g of CO₂ equivalent per kWh, respectively. This reduction in CO₂ emissions, in turn, reduces the effects of global climate change including increasing temperatures, rising sea levels, melting of sea ice, changing precipitation patterns, and ocean acidification.

• Energy independence: Being able to produce our own electricity in the U.S. without the aid of foreign countries is an important step to help us become more self-sufficient. Former President George W. Bush signed the Energy Independence and Security Act of 2007 to reduce U.S. dependence on oil, expand the production of renewable fuels (and confront global climate change). 

• Employment opportunities: The renewable energy sector collectively employed 12 million people worldwide in 2019. Renewable energy jobs continue to increase as we start to realize just how beneficial renewable energy is for our environment. 

What Are Environmental Drawbacks of Wind Energy

The three main concerns associated with wind energy are land use, wildlife impact, and public health. 

• Land use: wind farms take up a substantial amount of land, but the areas between and around turbines can be used for livestock grazing, agriculture, highways, and hiking trails. The amount of land disturbed when a turbine is constructed is minimal, and they can be sited on abandoned lands to further reduce land impacts. 

• Wildlife impact: turbine blades are large and pose a threat to flying wildlife such as birds and bats. While this is true, the threat is quite minimal. Extensive research and technological advances have reduced turbine-caused wildlife death. For example, turbines are kept motionless when wind speeds are low because bats are most active at these speeds.

• Public health: turbines can cause mechanical and aerodynamic noise pollution when constructed close to residential areas. Siting wind farms in remote locations or on abandoned lands can reduce this effect.

Proper planning and siting of wind farms can help mitigate these environmental drawbacks. 

Why Is Wind Energy Important to Fight Climate Change

Climate change is arguably the most severe, long-term, global impact of fossil fuel combustion. Every year, approximately 33 bt of CO₂ are emitted from burning fossil fuels. The carbon found in fossil fuels reacts with oxygen in the air to produce CO₂. This warms the earth by acting as a heating blanket, and a warmer earth comes with a host of negative side effects. 

Using wind energy instead of fossil fuel energy helps mitigate the following negative effects of climate change:

• Increasing temperatures: Earth’s atmosphere has warmed 1.5℃ since 1880. This may not seem like a lot, but these degrees create regional and seasonal temperature extremes, reduce sea ice, intensify rainfall and drought severity, and change habitat ranges for plants and animals.

• Rising sea levels: Global sea levels have increased approximately 8-9 inches since 1880, displacing people living along coastlines and destroying coastal habitats. Roads, bridges, subways, water supplies, oil and gas wells, power plants, sewage treatment plants, and landfills remain at risk if sea level rise goes unchecked. 

• Melting of sea ice: Since 1979, arctic sea ice has declined by 30%. Sea ice plays a major role in regulating the earth’s climate by reflecting sunlight into space and providing habitat for animal species. If all of the glaciers on Earth melted, sea levels would rise by approximately 70 feet, effectively flooding out every coastal city on the planet. 

• Changing precipitation patterns: Extreme weather events (e.g., hurricanes, floods, droughts) are becoming more common and more intense. Storm-affected areas will experience increased precipitation and flooding whereas areas located further from storm tracks will experience decreased precipitation and droughts.

• Ocean acidification: The ocean absorbs 30% of the CO₂ released into the atmosphere, which decreases the pH (increases the acidity) of the ocean. In the past 200 years, the pH of oceans has decreased by 0.1 pH units, which translates to a 30% increase in acidity. Aquatic life unable to adjust to this rapid acidification will die off. A prime example of this is coral bleaching, where coral expel the algae (zooxanthellae) living in their tissues as a result of changes in temperature, light, or nutrients. 

The more we reduce CO₂ emissions, the more we slow the rate of temperature rise, sea-level rise, ice melting, and ocean acidification. When these rates are slowed, the earth’s biodiversity does not have to struggle to adapt to temperature and pH changes. People will not be displaced due to the flooding of coastal areas. And icebergs will continue to provide climate regulation. 

To help keep global temperature rise below 1.5C, as outlined in the Paris Agreement, we must shift at least 80% of our electricity generation to low carbon sources. Over 120 countries have already stated their net-zero carbon emissions ambitions for 2050 or 2060. But only 12 countries have thus far proposed or enacted any legislation, indicating that there is more work to be done.

Final Thoughts

Wind energy currently makes up nearly a quarter of all renewable energy generation. Via wind turbines, moving air turns turbines and spins generators to produce electricity. If properly maintained, wind turbines can last 20 years and provide a low carbon emissions source of energy.

Wind energy is an environmentally friendly energy source with a low carbon footprint across its building, operating, and building back phases. It produces the lowest CO₂ emissions out of all energy types while creating jobs and promoting energy independence. Environmental concerns such as wildlife impact, land use, and noise pollution can all be mitigated by proper siting of wind farms. As we look towards a future powered by renewables, wind energy is a sustainable energy source that benefits both our atmosphere and Earth’s biota.

Stay impactful,

Sources

• Impactful Ninja: Renewable Energy Explained: All You Need to Know
• Impactful Ninja: Coal Energy Explained: All You Need to Know
• Impactful Ninja: Oil Energy Explained: All You Need to Know
• Impactful Ninja: Natural Gas Energy Explained: All You Need to Know
• Office of Energy Efficiency & Renewable Energy: How Do Wind Turbines Work?
• Kiwi Energy: Differences Between Onshore & Offshore Wind Energy
• NS Energy: Profiling ten of the biggest onshore wind farms in the world
• National Geographic: Wind Energy
• Conserve Energy Future: The Comparison of Horizontal and Vertical Axis Wind Turbines
• US Energy Information Administration: Wind Explained – Where Wind Power is Harnessed
• Our World in Data: Renewable energy
• Our World in Data: Renewable energy generation, World
• NS Energy: Profiling the top five countries with the highest wind energy capacity
• World Health Organization: Coronavirus disease (COVID-19) pandemic
• Global Wind Energy Council: Global Wind Report 2021
• International Energy Agency: Wind Power
• International Renewable Energy Agency: Wind Energy 
• Britannica: Carbon Footprint
• United States Environmental Protection Agency: System of Registries
• World Nuclear Association: Carbon Emissions from Electricity
• World Nuclear Association: Average life-cycle CO₂ equivalent emissions
• Impactful Ninja: What Is the Carbon Footprint of Wind Energy?
• US Environmental Protection Agency: Renewable Energy Fact Sheet – Wind Turbines
• Office of Energy Efficiency & Renewable Energy: Advantages and Challenges of Wind Energy
• White House Archives: Fact Sheet – Energy Independence and Security Act of 2007
• United States Environmental Protection Agency: Summary of the Energy Independence and Security Act
• International Renewable Energy Agency: Renewable Energy and Jobs
• Annual Review 2021
• Global Wind Energy Council: Wind power is crucial for combating climate change
• Union Of Concerned Scientists: Environmental Impacts of Wind Power
• Office of Energy Efficiency and Renewable Energy: Environmental Impacts and Siting of Wind Projects
• The National Wildlife Federation: Climate Change
• National Oceanic and Atmospheric Administration: Climate Change – Global Temperature
• National Oceanic and Atmospheric Administration: Climate Change – Global Sea Level
• United States Geological Survey: How would sea level change if all glaciers melted?
• National Aeronautics and Space Administration, U.S.A.: How does climate change affect precipitation?
• National Oceanic and Atmospheric Administration: Ocean Acidification
• National Ocean Service: What is coral bleaching?
• United Nations Framework Convention on Climate Change: The Paris Agreement
• International Energy Agency: Oil 2021