Wind power

Wind power is the process of capturing kinetic energy from moving air to perform useful work.

Historically, humans used wind for mechanical tasks using sails, windmills, or windpumps. Today, the primary application of wind energy is the generation of electricity. This is achieved through wind turbines, which are often organized into large groups known as wind farms. These farms connect to the electrical grid to distribute power to homes and industries. Wind power is considered a sustainable and renewable energy source. It has a much smaller environmental impact compared to the combustion of fossil fuels.

To understand how wind power works, we must look at the physics of the atmosphere. Wind is simply the movement of air within the Earth's atmosphere. The atmosphere acts like a thermal engine. It absorbs heat at higher temperatures and releases it at lower temperatures. This process creates wind kinetic energy at a rate of 2.46 W/m². The power available from the wind is proportional to the third power of the wind speed. This means that if the wind speed doubles, the available power increases eightfold.

This relationship makes wind speed a critical factor for energy production.

Most modern large-scale wind turbines follow a specific design. They are horizontal axis wind turbines. These machines feature an upwind rotor with three blades. The blades are attached to a component called a nacelle. This nacelle sits atop a tall, tubular tower.

When wind hits the blades, they rotate a shaft inside the nacelle. This rotation drives a generator to create electricity. Most turbines use variable speed generators. These are often paired with a power converter to ensure the electricity is stable for the grid. In a wind farm, turbines are spaced apart to prevent interference. A common distance is 7D, which is seven times the diameter of the rotor.

Wind farms are categorized by their location as either onshore or offshore. Onshore wind farms are built on land. These are often cheaper to build and maintain. However, they can have a greater visual impact on the landscape. Offshore wind farms are located in large bodies of water, such as the sea.

These installations can access more frequent and powerful winds. This leads to higher capacity factors, which is the ratio of actual energy produced to the theoretical maximum. Offshore wind currently makes up about 10% of new installations. The Hornsea Wind Farm in the United Kingdom is a notable example. It is the largest offshore wind farm, with a capacity of 1,218 MW.

As wind power expands, engineers face challenges with the electrical grid. Wind is a variable energy source, meaning it does not blow constantly. Because of this, wind power requires energy storage or other dispatchable sources to maintain a reliable supply.

Another challenge is transmission. Wind resources are often located in remote, sparsely populated areas. This is far from the high-density cities that need the power. Long transmission lines can lead to energy losses. If the grid cannot handle the amount of power being produced, a process called curtailment occurs. This is when wind farms must stop running or produce less than they are capable of to prevent grid overload.

Global wind energy production has seen massive growth in recent years. In 2024, wind supplied approximately 2,494 TWh of electricity. This accounted for about 8.1% of the world's total electricity production.

The global installed capacity for wind power has exceeded 800 GW. During 2021, about 100 GW of new capacity was added, mostly in the United States and China. Wind generation has nearly tripled since 2015. In 2024, 30 countries generated more than one-tenth of their electricity from wind. To meet the goals of the Paris Agreement regarding climate change, analysts suggest wind power must expand by over 1% of total electricity generation every year.

Wind power is highly compatible with other renewable energy systems. In many regions, wind speeds are higher during the night or in the winter. This is often when solar power output is at its lowest.

Combining wind and solar power can create a more stable energy supply. Furthermore, wind is one of the lowest-cost sources of electricity per unit of energy produced. In many locations, building new onshore wind farms is more economical than building new coal or gas plants.

This makes wind a central part of the global transition to cleaner energy systems.