The compromise I had to make, especially with the third site, is a longer wire run. However, wire cost constitutes a small percentage of the cost of an entire wind system installation. More important was getting upwind of the major sources of turbulence at our site—a strategy that will help optimize energy generation and reduces wear and tear on the equipment.
You should be able to access a wind rose for your location from your state energy office or wind map, or local agricultural office. The U.S. Department of Agriculture’s Natural Resources Conservation Service has downloadable wind roses from various climate stations (see Access). Other good sources of prevailing wind directions include the National Oceanic and Atmospheric Association or Weather Underground, both of which keep local climatological data.
So, what can we take from all of this? The lessons are pretty straightforward:
The economic payback in a wind turbine is directly proportional to the electricity it generates over its life. If a wind turbine is sited in turbulent winds, it simply will not generate much electricity, making it a questionable investment. In addition, the turbulence will cause increased wear and tear on the turbine, shortening its useful life. But a wind system includes more than just the turbine—it includes a tower that’s properly sized for the site, foundation, wire run, balance-of-system components, all labor and materials for installation, and various other costs.
People take care of investments when they make sense. Wind system owners invest maintenance and repair dollars in things that work, like a properly sized and sited wind turbine. Owners quickly abandon ideas that don’t work. The history of small wind tells us that rooftop wind turbines and wind turbines installed on towers too short for the site are quickly abandoned and become derelict once they need repair. Simply put, they were bad investments. A $20,000 wind-electric system that only lasts for two years is a poor investment compared to an $80,000 system that lasts 20 years.
If you are shopping for a wind turbine, where do you go for help? Three organizations host websites with recommendations based on equipment that is certified to an American National Standards Institute standard, actual performance test results, and industry feedback.
The Small Wind Certification Council (SWCC) is a certifying body that confirms that published turbine test results conform to the American Wind Energy Association’s 9.1-2009 Small Wind Turbine Performance and Safety Standard. Turbines that are certified to have met the AWEA 9.1 criteria are listed at smallwindcertification.org. Make sure you peruse the list of SWCC-certified turbines, not the applicant turbine status.
The Interstate Turbine Advisory Council (ITAC) is a consortium of state public-benefits programs that fund the installation of renewable energy systems. They publish the Unified List of Wind Turbines (at bit.ly/ITACturbines) that participating state programs may be willing to fund.
Intertek is another organization that certifies wind turbine test results to the AWEA 9.1-2009 standard. However, this website (bit.ly/IntertekDirectory) is a bit more confusing since Intertek certifies components as well as entire wind turbines.
If the wind generator you are considering is not on one of these three lists, move on. Or at least understand that you are making a risky purchase of an untested, unproven design, and be ready to accept the outcome of your speculative investment.
Mick Sagrillo consults, teaches, and writes about wind power. He and his wife have powered their house with wind for 32 years, and Mick has flown dozens of models during that time.
Downloadable wind roses • bit.ly/NRCSWindRose