Vertical-axis wind turbine

This arrangement allows the generator and gearbox to be located close to the ground, facilitating service and repair.

Major drawbacks for the early designs (Savonius, Darrieus and giromill) included the significant torque ripple during each revolution and the large bending moments on the blades.

Later designs addressed the torque ripple by sweeping the blades helically (Gorlov type).

[3] Savonius vertical-axis wind turbines (VAWT) are not widespread, but their simplicity and better performance in disturbed flow-fields, compared to small horizontal-axis wind turbines (HAWT) make them a good alternative for distributed generation devices in an urban environment.

The Darrieus rotor comes in various subforms, including helix-shaped, disc-like, and the H-rotor with straight blades.

These turbines typically have three slim rotor blades driven by lift forces, allowing them to achieve high speeds.

In practice, you may come across a range of variations and combinations, with developers frequently demonstrating their creativity in crafting diverse forms of vertical wind turbines.

The original design included a number of curved aerofoil blades with the tips attached on a rotating shaft.

However, there are also designs that use straight vertical airfoils, referred to as H-rotor or Giromill Darrieus wind turbines.

Revolving wing wind turbines or rotating wing wind turbines are a new category of lift-type VAWTs which use 1 vertically standing, non-helical airfoil to generate 360-degree rotation around a vertical shaft that runs through the center of the airfoil.

[17][18][19] The blades of a VAWT are fatigue-prone due to the wide variation in applied forces during each rotation.

The vertically oriented blades can twist and bend during each turn, shortening their usable lifetimes.

Other than the drag-types, VAWTs have proven less reliable than HAWTs,[20] although modern designs have overcome many early issues.

One effect is to avoid downstream turbulence stemming from grid-arranged HAWTs that lowers efficiency.

Other optimizations included array angle, rotation direction, turbine spacing, and number of rotors.

[23] In 2022 Norway's World Wide Wind introduced floating VAWTs with two sets of counter-rotating blades.

VAWTs place most of the heavy components at the bottom of the tower, reducing the need for counterbalance.

[24] The Windspire, a small VAWT intended for individual (home or office) use was developed in the early 2000s by US company Mariah Power.

[25] Arborwind, an Ann Arbor, Michigan, based company, produces a patented small VAWT which has been installed at several US locations as of 2013.

[26] In 2011, Sandia National Laboratories wind-energy researchers began a five-year study of applying VAWT design technology to offshore wind farms.

[27] The researchers stated: "The economics of offshore windpower are different from land-based turbines, due to installation and operational challenges.

A 24-unit VAWT demonstration plot was installed in southern California in the early 2010s by Caltech aeronautical professor John Dabiri.

[28] Dulas, Anglesey, received permission in March 2014 to install a prototype VAWT on the breakwater at Port Talbot waterside.

[31] Architect Michael Reynolds (known for his Earthship house designs) developed a 4th-generation VAWT named Dynasphere.