Vertical Axis Wind Turbines (VAWTs) are an attractive alternative to the widespread Horizontal Axis Wind Turbines (HAWTs). VAWTs offer a number of specific advantages and challenges, as well as a distinct history and future outlook.
How VAWTs work
VAWT wind turbines have a vertical axis of rotation perpendicular to the ground, and blades arranged around this axis. There are two main types of VAWT: rotary-wing wind turbines (Darrieus) and propeller wind turbines (Savonius). Darrieus turbines use curved, aerodynamic blades, while Savonius turbines have S-shaped or shell-shaped blades. VAWTs capture the wind whatever its direction, unlike HAWTs, which must face into the wind.
Advantages and disadvantages
Advantages
VAWTs offer specific environmental advantages. Their design allows the generator and other mechanical components to be placed at ground level, facilitating maintenance and reducing risks to wildlife. In addition, VAWTs are generally quieter than HAWTs and have less visual impact, making them more suitable for urban or residential environments.
VAWTs are more flexible in terms of installation, as they can be used in areas with turbulent or changing wind conditions, such as urban areas. However, their energy efficiency is generally lower than that of HAWTs.
Disadvantages
Among the challenges and drawbacks associated with VAWTs is their low energy efficiency, particularly when compared with HAWTs. In addition, the production cost of VAWTs is generally higher due to the complexity of their design and manufacture. Finally, the durability of VAWTs is often limited by mechanical constraints and wear problems on moving parts.
Historical development
VAWTs have a long history, dating back to the Persian windmills of the 9th century. Over the years, several inventors and engineers have contributed to improving VAWT design. Among the most notable, Georges Darrieus developed the rotary-wing wind turbine in 1927 and Sigurd Savonius designed the propeller wind turbine in 1922. Since then, technological advances have improved VAWT performance and made them more competitive in the renewable energy market.
VAWT development
Projects
Several projects around the world have adopted VAWT technology. One notable example is the Østerild wind farm in Denmark, which is testing and evaluating different VAWT designs. Another example is the American “Icewind” project, which is developing small VAWTs for extreme climates and remote regions.
VAWT turbine companies and manufacturers
Companies developing VAWTs include UGE (Urban Green Energy), which offers VAWT solutions for urban areas and buildings. Helix Wind, a US company, develops VAWTs for residential and commercial applications, while Windspire Energy focuses on small VAWTs for rural areas and remote sites. Finally, Icewind, an Icelandic company, is developing VAWTs specially designed to withstand extreme climatic conditions, such as those encountered in polar regions.
Future prospects
Future prospects for VAWT technology are promising, thanks in particular to technological advances that could improve their efficiency and durability. Researchers and engineers are working on new blade designs, stronger materials and more advanced control systems to optimize VAWT performance. In addition, government policies and financial incentives in favor of renewable energies could encourage the deployment of this technology.