Small Wind Turbines

Harnessing the power of the wind has begun to recapture the imagination of America. Returning to a technology that was prevalent during colonial times has become an intriguing idea to many people including many residents of Montgomery County. The county, with its mix of rural, suburban, and urban areas, provides many opportunities for residents to incorporate into their homes. Wind energy is an emerging technological approach to energy production that can have positive economic and environmental impacts for those committed to the cause of . The Technology

Today’s wind turbines are a far cry from the large, wooden turbines of colonial times. Modern technology has allowed wind turbines to become smaller, lighter, more durable, and much more efficient. Small wind

Vertical axis in a residential setting. turbines are defined as having an energy generation capacity of 100 kilowatts per hour (kWhrs) and less. The standard commercial ratings for a wind turbine are determined using the peak production values possible for that size turbine. Actual energy production will fluctuate due to the unpredictable nature of wind. A typical household uses roughly 950 kWhrs a month, so the energy production of a small wind turbine can create a substantial amount of cost savings.

Wind turbines come in a wide range of styles and sizes. They typically have a horizontal axis or a vertical axis. The horizontal- axis wind turbine is most commonly used today. It is characterized by the propeller shape of the turbine and usually uses three blades. The vertical-axis design, like the eggbeater-style Darrieus model, named after its French inventor, is less common. Studies show at this point the technology is less efficient, less reliable, and more expensive than the horizontal variety. The Darrieus model is more visually appealing to some people, and new technologies may make this a more economically viable option in the future.

Other wind turbine technologies, which do not exactly fit into the two main types, have begun to emerge. These technologies will continue to evolve, becoming more efficient and affordable as demand increases. Municipalities and their residents should try and keep current on the latest wind turbine technologies.

Benefits and Considerations

Reduced carbon emissions. One residential-scale turbine can displace the carbon emissions from 1.5 cars.

Clean energy. There are no emissions, water use, or hazardous waste associated with wind turbine use. Though, as with almost any manufactured product, the production and installation of wind turbines leaves a carbon footprint that should be considered.

Save money. A 5-15 kWh turbine can reduce a residence’s annual electricity bill by 50 percent.

Installation costs. A small turbine can cost anywhere from $6,000 to $22,000 installed, depending upon size, application, and service agreements with the manufacturer.

Property value. While only a few studies may exist, they generally show an increased property value for those owning a wind turbine and no decrease in neighbors’ property values.

Emergency back-up power if necessary. Wind turbines Top photo: View from the base of a horizontal wind turbine. can generate power for a building when the experiences failure. Middle photo: Vertical-axis wind turbine.

Bottom photo: Rooftop wind turbines at the University of Arizona. A

W Benefits. It is crucial to understand the importance Wind Speeds Increase with Height of net metering. Net metering is a way to calculate the energy 150 consumed and produced on a site containing its own alternative

Courtesy of AE energy generator, such as a wind turbine. Using net metering, the excess electricity produced by the wind turbine will spin the 120 electricity meter backwards, effectively banking the electricity until it is needed by the customer. This allows the owner of the wind turbine to be compensated for any excess electricity 90 produced. Net metering is required of utilities in Pennsylvania and is an important motivator for the implementation of alternative energy systems. 60 Tower height,Tower ft Maintenance. Wind turbines have very few moving parts. This simplicity creates a higher degree of reliability than other

30 energy production systems that are more complex. Most manufacturers suggest that wind turbines undergo maintenance by a professional every few years and it is estimated that a small

0 wind turbine can have a lifespan of 20 years or more. 0 41 75 100 124 Increase in wind power, %

A Regulatory Considerations Wind Turbulence Effects W 10-kilowatt Height. The higher the turbine the better. When wind is disturbed by surrounding structures or natural obstacles the 400-watt Courtesy of AE wind turbine loses speed and a degree of its power-generation Prevailing Winds potential. The higher a wind turbine can arise above any possible obstacles, the more efficiently the turbine will produce power. 30’ Studies show that the turbine should be at least 30 feet above the Region of High 80’-120’ Turbulence Flow 35’-50’ Tower Tower nearest obstruction within 300 feet. This will allow the turbine to capture the strongest winds. Safety and visual considerations 500 feet must be taken into account when regulating the height. A

W Setbacks. Setbacks on a property are an important consideration Wind Turbine Noise Comparison due to the height of wind turbines. The setback requirements can Decibels be based on turbine height or by requiring a minimum lot size. Courtesy of AE Jet Airplane Noise. Small-scale wind turbines are much quieter than commonly thought, but to ensure the turbine is not a noise Pneumatic drill nuisance, many regulations set a decibel limit at property lines. It is important to take the setting (rural versus urban) Industrial Noise and acceptable nighttime decibel levels into account when

Stereo music considering decibel regulations. Inside car Aesthetics. Visual impact is one of the most difficult challenges Office Home for residential wind turbines. Appearance is difficult to regulate, but some language is available to handle the issue. This language Wind turbine could include ground-level screening and buffering requirements Bedroom as well as regulation of wind turbines in the line-of-sight of scenic or cultural resource areas.

Whisper Falling leaves Safety. There are a series of regulations that can be adopted to ensure an adequate level of safety. These include building and electrical code requirements along with possible fencing and other climbing deterrents.

Bird and bat mortality. An issue frequently associated with wind turbines is the rate of bird and bat kills due to collisions with the turbine. This subject is being explored by scientists. The most recent information points to wind turbines being no more dangerous to birds and bats than other tall structures, though animal deaths may occur. To be safe, wind turbines should be setback from Important Bird Areas and from identified wetlands.

For more information, please contact the Montgomery County Planning Commission at 610.278.3722 or visit our site online at Montgomery County Planning Commission www.planning.montcopa.org to see the complete renewable Montgomery County Court House energy series and other resources. PO Box 311, Norristown, Pennsylvania 19404 Printed on recycled paper Printed in 2011 website: www.planning.montcopa.org