Wind power: generating electricity from the wind

Wind power, which has its roots in the historic use of windmills, has recently become an essential source ofrenewable energy. Modern wind turbines convert the wind’s kinetic energy into electricity using ingenious, high-performance systems. Their lifecycle, from design to end-of-life, is designed to minimize their environmental impact and optimize their efficiency. In addition to conventional technologies, a number of innovations such as flying, blade-less and urban wind turbines are boosting the sector.

How wind power works

Wind power is a renewable energy source that harnesses the power of the wind to generate electricity. Wind turbines, consisting essentially of a mast, nacelle and rotors, capture the kinetic energy of the wind. When the wind blows, it turns the blades, which are connected to a rotor. This rotor drives a generator located in the nacelle, transforming mechanical energy into electricity. The electricity generated is then fed into the power grid. The better the location, the higher the efficiency.

Blade length plays an important role in wind power generation. Longer blades can capture more energy by covering a larger swept area. According to the International Energy Agency (IEA), the output of onshore wind turbines has increased considerably in recent decades, from around 50 kW with 15-meter blades in the 1990s to almost 4 MW with 130-150-meter blades by 2021.

This increase in the size of wind turbines has led to improved productivity and efficiency. Energy production is proportional to the square of the blade length and to wind speed at third power. Thus, a wind turbine with blades twice as long can theoretically capture four times as much energy, while a 10% increase in wind speed can lead to a 33% increase in energy production.

The life cycle of wind turbines

The life cycle of wind turbines comprises several stages: planning, construction, operation and dismantling. Planning involves wind resource assessment, environmental impact assessment, obtaining the necessary permits and project design. Construction includes site preparation, foundation installation, turbine assembly and connection to the power grid.

Operation generally lasts between 20 and 25 years, during which time the turbines generate electricity and require regular maintenance to keep them running smoothly. At the end of their service life, the turbines are dismantled and the materials recycled wherever possible. The site can then be restored or reused for new wind energy projects.

Wind power technologies

Blade type

Wind energy technologies can be divided into two categories: horizontal-axis wind turbines (HAWT) and vertical-axis wind turbines (VAWT). HAWTs, the most common type, feature blades mounted on a rotor parallel to the ground, rotating around a horizontal axis. VAWTs have a rotor perpendicular to the ground and rotate around a vertical axis. Finally, there are some rather special wind turbines: they have no blades.

Horizontal axis wind turbines (HAWT)

HAWTs are currently the dominant technology in the wind power industry. By 2020, over 99% of the world’s installed wind power capacity will be horizontal-axis turbines (source: Global Wind Energy Council). HAWTs are more energy-efficient than VAWTs, and are able to capture stronger winds at higher altitudes thanks to taller masts. However, they generally require more space and initial investment to install. HAWTs are also more visible and can generate noise pollution.

Vertical axis wind turbines (VAWT)

VAWTs account for a small share of the wind energy market, but offer certain advantages over HAWTs. They capture the wind independently of its direction and can be installed at lower altitudes, reducing visual impact and facilitating maintenance. VAWTs are also less sensitive to turbulence and may be more suited to urban areas or complex environments. However, their energy efficiency is generally lower than that of HAWTs, and they have a more limited power generation capacity.

Although horizontal-axis wind turbines currently dominate the wind energy market, vertical-axis wind turbines offer potential for innovation and could play a more important role in the future, particularly in specific contexts such as urban environments or small decentralized wind systems.

Bladeless wind turbines

Bladeless wind turbines represent an innovative approach to wind power generation, seeking to solve some of the problems associated with traditional bladed wind turbines. By exploiting concepts such as the vortex effect, biomimicry and wind kites, these technologies aim to reduce production costs, environmental impact and noise pollution. Notable companies working on these solutions include Vortex Bladeless, Saphon Energy, Tyer Wind, kPower and ENESSERE, each offering unique approaches to capturing wind energy without the use of blades. Although these technologies are still at an early stage of development, they are technologically interesting avenues that could address major weaknesses in conventional wind power.

Offshore or onshore wind power?

There are several wind turbine technologies, depending on their location:

  • Onshore wind turbines are installed on land, and account for the majority of installed wind power capacity worldwide. They are generally less expensive to build and maintain than offshore wind turbines. However, onshore wind turbines can experience weaker and less constant winds than offshore wind turbines. What’s more, their impact on the landscape and noise pollution can pose problems of social acceptability and limit the sites available for their installation.
  • Offshore wind turbines are installed at sea, generally several kilometers from the coast. They benefit from stronger, more constant winds, which increases their productivity. Offshore wind turbines also have a reduced visual and noise impact on people. However, their construction, installation and maintenance are more costly and complex due to difficult marine conditions. One way of facilitating their implementation is to install them on floating systems, but this avenue is still experimental. Offshore wind turbines can also have an impact on marine ecosystems and human activities at sea, such as fishing and shipping.
  • Flying wind is an emerging technology that aims to harness winds at high altitudes, where speeds are generally higher and more constant. By using flying devices such as kites, balloons or drones to harness the wind’s energy, this approach promises more efficient and less costly renewable energy production. However, it is still at an experimental stage.
  • There are also plans to integrate wind power generation into urban and peri-urban environments using urban wind turbines. These are generally small, silent and adapted to the specific wind conditions of urban areas. Designed to be aesthetically pleasing and functional, urban wind turbines can be installed on rooftops, facades or public spaces, enabling local, decentralized energy production. On the other hand, they are less productive.

Technological innovations: the future of wind turbines

Technological innovations in the field of wind energy aim to improve the efficiency, reliability and profitability of wind turbines. Recent and future developments include :

  1. Floating wind turbines: These make it possible to exploit deeper offshore sites, where winds are stronger and more constant. Floating turbines can be anchored to the seabed and offer considerable potential for offshore wind power generation.
  2. Advanced materials and designs: Advances in materials and blade design aim to reduce weight and increase the durability, efficiency and performance of wind turbines.
  3. Artificial intelligence and advanced control: The use of AI and innovative control systems enables wind turbine performance to be optimized in real time, by adjusting blade position and orientation according to weather conditions.

Advantages and disadvantages of wind power

Advantages:

  • Renewable and clean: Wind power is an inexhaustible source of energy that emits no greenhouse gases or atmospheric pollutants.
  • Low operating costs: Once installed, wind turbines have relatively low operating costs and can offer competitive electricity prices.
  • Job creation: The wind energy sector generates jobs in the manufacture, installation and maintenance of wind turbines.

Disadvantages :

  • Intermittence: Wind power generation is weather-dependent and can be irregular.
  • Landscape and noise impact: Wind turbines can alter the landscape and generate noise pollution for nearby residents.
  • Impact on wildlife: Wind turbines can cause bird and bat mortality due to collisions with the blades.

Wind farms around the world

The development of wind power worldwide has grown rapidly in recent years. According to the Global Wind Energy Council (GWEC), global installed wind capacity reached 743 GW by the end of 2020, with an increase of 53 GW over 2019. China and the USA are the two largest wind energy markets, accounting for 264 GW and 122 GW of installed capacity respectively in 2020.

Offshore wind power is also expanding rapidly. By the end of 2020, global offshore wind capacity was 35 GW, with Europe accounting for almost 75% of this capacity (source: GWEC). The UK is the world leader in offshore wind, with installed capacity of 10.4 GW in 2020, followed by Germany (7.7 GW) and China (6.8 GW) (source: WindEurope).

In terms of share of electricity generation, wind power accounted for around 6.1% of global electricity production in 2020 (source: BP Statistical Review of World Energy 2021). Growth in wind power is set to continue in the years ahead, thanks to supportive policies and efforts to meet international climate targets.


How much energy does a wind turbine produce?

Wind turbine energy is the electricity generated by converting the kinetic energy of the wind.

How does wind power work?

Wind energy works by capturing the wind with blades that drive a rotor, generating electricity.

What are the advantages and disadvantages of wind power?

The advantages of wind power include sustainability, reduced emissions and job creation; the disadvantages include intermittency, visual impact and noise.

What are the downsides of wind turbines?

Negatives include intermittency, visual impact, noise and maintenance costs.

How much does a wind turbine cost?

The cost of a wind turbine varies according to size and technology, ranging from a few thousand to several million euros.

Do wind turbines run without wind?

Wind turbines do not run without wind, but thanks to their design they can operate in low winds.