Vertical-axis wind turbines, or VAWTs as they are often referred to as, are wind turbines that have their rotor shaft arranged vertically instead of horizontally. Instead of being mounted horizontally atop a large base like horizontal-axis wind turbines (HAWTs), VAWTs are mounted vertically — the blades of the turbine stand tall straight up and down. Many home wind power systems are comprised of VAWTs, as there are now many manufacturers making small wind turbines for home use. I had trouble keeping track of which company was which!
Earlier this year I wrote about building your own vertical axis wind turbine at home. Backyard wind power, which used to be just a hobby for a select few self-sufficient folks, has become big business as residents are looking for renewable energy sources to power their homes and small businesses. There are several types of vertical wind turbines available, along with advantages and disadvantages of them, that potential buyers should be aware of before making any decision.
Vertical Wind Turbine Types
There are three types of vertical wind turbines currently found in use, depending on the application.
The Savonius wind turbine was invented by Sigurd J. Savonius in 1922. This turbine generally looks like two opposed halves of a barrel or ball spinning around the central rotor. These two halves create air scoops which capture the wind and in-turn spin the turbine, generating power. It is the least efficient of VAWTs.
The Darrieus wind turbine looks like an egg beater you may find in any kitchen around the world. Simple in design, the Darrieus was invented invented by Georges Darrieus in 1931. It works using aerofoils, which is similar to the principle behind how an airplane in motion stays in the air as air flows over and under the wings.
The Helical wind turbine is a slightly more complicated version of the Darrieus turbine, in that it consists of three vertical airfoil blades spinning in a helical pattern around each other. This is the newest design for VAWTs and the most efficient.
Advantages of Vertical Axis Wind Turbines
There are several advantages to using a vertical axis turbine rather than a horizontal turbine. First off all, they are much smaller in size; not too many people (or their neighbors) want a gigantic 100 foot tall wind turbine in their backyard. I know I wouldn’t want one of those towering above my home! A few more advantages include:
- The turbine does not need to be facing the wind in order to be generating energy. There is no yaw (part that helps angle the propellors of a typical wind turbine into the wind) necessary as the unit doesn’t have to move into the wind to spin.
- Any equipment that goes along with operating a turbine can be placed on the ground, where it is easier to get at and maintain in the event of a malfunction. No climbing up a steep metal ladder to the top of a horizontal turbine.
- They can be installed on suburban roofs with less permitting problems and without offending the neighbors
- Vertical wind turbines are more affordable than a typical HAWT wind turbine for home energy creation
- These vertical units do not have to shut down in high winds
- Residential customers are currently eligible for a 30% federal tax credit for purchase and installation of a small wind power generator, in addition to any state incentives.
Disadvantages of Vertical Axis Wind Turbines
While the advantages of a VAWT far outweigh any disadvantages, there are a few things that those interested in wind power generation should be aware of, including:
- VAWTs can be up to 50% less efficient than a HAWT do to their lower height and exposure to higher winds
- For all the spinning they may do they generate less power, meaning you could require more of them to provide for your power needs
- These units can generate more vibrations on the ground and surrounding areas in turbulent winds, which could lead to noises and an uncomfortable living environment if they are near (or on) your house.
- VAWTs require guyed wires attached to the turbine and the ground to help hold everything down and prevent it from flying away!
Vertical Wind Turbine Companies
If you go looking for a vertical wind turbine for your home power needs, good luck — there are a seemingly endless number of companies looking to sell you their latest and greatest turbine. In order to narrow down the field, I went and looked for some of the more popular, well-known vertical-axis wind turbine manufacturers for you to check out:
While solar energy seems to be the first thing people think of when contemplating going green at home with renewable energy, home wind turbine systems are definitely a close second. Vertical wind turbine design is continually evolving and becoming more mainstream and affordable, so we can assume that the general population will continue to adopt wind power as a reliable source of clean power.
I know I plan on installing a wind turbine on my property to supplement the energy I will get from solar panels, and with the price dropping and units becoming more efficient, I know that a VAWT will add value to my house while reducing my utility bills.