Getting a Building Permit
A wind turbine is a structure that requires a building permit. Zoning regulations often limit the height, placement, and other characteristics of "appurtenant" structures, so a conditional (special) use permit or variance may be necessary. It's usually best to let your neighbors know about your installation. Be prepared to answer questions and clear up common misconceptions with well-documented facts about small wind turbines.
- General Starting Information
- Conditional (Special) Use Permits
- Letting Your Neighbors Know: Tips for Public Hearings
- Useful Links
General Starting Information: Contact County Planning or Permitting Department to find out what zoning regulations apply to appurtenant, or non-dwelling, structures on your property. Ask if small wind energy systems are specifically addressed by local ordinance, and if so get a copy of the ordinance. You'll need to know the permitting procedures and find out what documentation is required for your turbine. You may have to submit a structural plan drafted by an engineer, but documents from your turbine manufacturer or dealer may be enough.
Conditional (Special) Use Permits
If zoning rules list small or residential wind turbines as an approved "conditional" or "special" use for your property, you need only comply with the relevant conditions -- which usually pertain to minimum lot size, maximum tower height, setbacks, and electrical code compliance. The manufacturer or dealer may be able to help with the documentation.
If small wind turbines are not an allowed use, you may have to apply for a conditional use permit, which could involve public hearings before you local planning board.
Check local land-use codes carefully for special zoning ordinances that authorities may have overlooked. A turbine owner in California avoided turbine tower height restrictions through a forgotten wind energy zoning ordinance that had been passed decades earlier.
A zoning variance is a project-specific exception from existing zoning regulations. If the zoning code prohibits structures more than 35 feet, tall, for example, a wind turbine will probably need a variance from the rule unless special provisions have already been inserted for wind energy systems. Local county or city planning boards usually have to approve variances.
An application for a variance should cite the specific rule and list reasons why a structure should be accepted. Height restrictions are a common barrier for wind turbine applicants, who often find height limits set at 35 feet because fire trucks could not pump water higher than that when the code was written. These rules are now obsolete, but residents may nevertheless insist on preserving them because they feel taller structures would negatively alter the neighborhood's appearance. You should be prepared to explain that the impact of your wind turbine will be minimal. Take note of other tall structures neighbors already accept: water towers, rooftop satellite dishes, cellular communications towers, etc.
Letting Your Neighbors Know...Tips on Public Hearings
BE PREPARED to answer questions about your project, especially if you have to appear at a public hearing seeking a conditional use permit or variance (Conditional or special use permits do not always require hearings, but a variance will). A hearing may turn out to be a mere formality, but be ready for anything that might come up. Here are some tips:
- Seek the support of your neighbors before the hearing. See AWEA's "Sample Letters"
- Compile documented factual information to reassure anyone worried about noise, visual impact, possible affects on wildlife, and property values. See AWEA's "Factsheets."
- Planning and zoning officials may be unfamiliar with small wind energy systems, so be prepared to explain the basics. It's helpful to have photographs of similar installations. See AWEA's "Success Stories."
About Permitting Fees ...
Permitting requirements, procedures, and fees vary widely among counties. Fees for building permits, use permits, zoning permits, and "plot plans" can range from $400 to $1,600. There may be other fees for public notification, hearings, and environmental impact studies costing from a few hundred to several thousand dollars.
Remember, if a fee seems inappropriate or excessive, you may be able to get it reduced or waived. Find out what you are being charged for and offer to provide documentation or information that makes the fee unnecessary.
Some Useful Links
- Permitting Small Wind Turbines: Learning from the California Experience
- Windmills and Zoning Boards site
- AWEA Zoning FAQ
- Small Wind Fact Sheet
A: Federal Credits and State Rebate Programs
On January 22 2009, President Obama signed into law a new federal-level investment tax credit to help consumers purchase small wind turbines for home, farm, or business use. Owners of small wind systems with 100 kilowatts (kW) of capacity and less can receive a credit for 30% of the total installed cost of the system. The credit will be available through December 31, 2016.
Consumers will receive the Investment Tax Credit (ITC) in the year the system is installed. The consumer’s tax liability will be reduced by the amount of the credit allowed via Form 3468, Investment Credit, when filing their yearend tax return with the IRS. The credit is exempt from Alternative Minimum Tax (AMT) and therefore applies even if the taxpayer is subject to AMT. If the credit is larger than the consumer’s tax liability and not fully utilized in the year installed, it can be carried back 1 year to offset any previous tax liability or carried forward 2 years to offset future tax liability.
To apply for this tax credit follow this link and consult your tax adviser.
Illinois also offers a rebate and more information can be found here. Download the Rebate Form. (Expires April 30, 2010)
Wisconsin offers a rebate, more information can be found here or download the rebate form. (Expires Jan. 31, 2010)
Q: How does Net Metering work?
A. “Net-metering” is a simplified method of metering the energy consumed and produced at a home or business that has its own renewable energy generator, such as a small wind turbine. Under net metering excess electricity produced by the wind turbine will spin the existing home or business electricity meter backwards, effectively banking the electricity until it is needed by the customer. This provides the customer with full retail value for all the electricity produced. Without net metering the excess production is sold to the utility at a much lower price. Under existing federal law (PURPA, Section 210) utility customers can use the electricity they generate with a wind turbine to supply their own lights and appliances, offsetting electricity they would otherwise have to purchase from the utility at the retail price. But if the customer produces any excess electricity (beyond what is needed to meet the customer’s own needs), the utility purchases that excess electricity at the wholesale or ‘avoided cost’ price, which is much lower than the retail price. The excess energy is metered using an additional meter that must be installed at the customer’s expense. Net metering simplifies this arrangement by allowing the customer to use any excess electricity to offset electricity used at other times during the billing period. In other words, the customer is billed only for the net energy consumed during the billing period.
Q. Why is net metering important?
A. There are three reasons net metering is important. First, because wind energy is an intermittent resource, customers may not be using power as it is being generated, and net metering allows them to receive full value for the electricity they produce without installing expensive battery storage systems. This is important because it directly affects the economics and pay-back period for the investment. Second, net-metering reduces the installation costs for the customer by eliminating the need for a second energy meter. Third, net metering provides a simple, inexpensive, and easily-administered mechanism for encouraging the use of small-scale wind energy systems, which provide important local, national, and global benefits to the environment and the economy.
Q. What are the benefits and costs of net metering?
A. Net metering provides a variety of benefits for both utilities and consumers. Utilities benefit by avoiding the administrative and accounting costs of metering and purchasing the small amounts of excess electricity produced by small-scale wind energy facilities. Consumers benefit by getting greater value for some of the electricity they generate and by being able to interconnect with the utility using their existing meter. The only cost associated with net metering is indirect: the customer is buying less electricity from the utility,
which means the utility is collecting less revenue from the customer. That’s because any excess electricity that would have been sold to the utility at the wholesale or ‘avoided cost’ price is instead being used to offset electricity the customer would have purchased at the retail price. In most cases, the revenue loss is comparable to having the customer reducing electricity use by investing in energy efficiency measures, such as compact fluorescent lighting, efficient heating and cooling equipment, or other highly- efficient appliances.
The bill savings for the customer (and corresponding revenue loss to the utility) will depend on a variety of factors, particularly the difference between the ‘avoided cost’ and retail prices and the amount of excess electricity produced.
Q. Can I really use my existing meter to take advantage of net metering?
A. The standard kilowatt-hour meter used for most residential and small commercial customers accurately registers the flow of electricity in either direction. This means the ‘netting’ process associated with net metering happens automatically — the meter spins forward (in the normal direction) when the customer needs more electricity than is being produced, and spins backward when the customer is producing more electricity than is needed in the home or building. The meter registers the net amount of energy produced or consumed during the billing period.
To find out whether net metering is available in your location, contact the American Wind Energy Association at the address below, or go to the policy area of the AWEA web site, and follow the links regarding net metering.
Source: Kathy Belyeu, American Wind Energy Association, (202) 383-2504
Q; How much does electricity cost?
A: The cost of electricity depends on where you live, how much you use, and possibly when you use it. There are also fixed charges that you pay every month no matter how much electricity you use. For example, I pay $6/mo. for the privilege of being a customer of the electric company, no matter how much energy I use.
Check your utility bill for the rates in your area. If it's not on your bill then look it up on the utility's website.
The electric company measures how much electricity you use in kilowatt-hours, abbreviated kWh. Your bill might have multiple charges per kWh (e.g., one for the "base rate", another for "fuel") and you have to add them all up to get the total cost per kWh.
Most utility companies charge a higher rate when you use more than a certain amount of energy, and they also charge more during summer months when electric use is higher. As an example, here are the residential electric rates for Austin, Texas (as of 11-03):
|First 500 kilowatts
||5.8¢ per kilowatt hour (kWh)
|Additional kilowatts (May-Oct.)
||10¢ per kilowatt hour
|Additional kilowatts (Nov.-Apr.)
|| 8.3¢ per kilowatt hour
These figures include a fuel charge of 2.265¢ per kWh.
The average cost of residential electricity was 9.86¢/kWh in the U.S. in March 2006. The average household used 888 kWh per mo. in 2001 and would pay $87.56 for it based on the March 2006 average rate. (Dept. of Energy)
The cost of electricity varies by region. In 2003 the price ranged from 5.81¢ in Tennessee to 12¢ in California, 14.314¢ in New York, and 16.734¢ in Hawaii. In summer 2001, electricity was a whopping 20¢/kWh in parts of California.
Source: Michael Bluejay
Q: What is kilowatt hour?
Watts - The rate of electrical use at any moment is measured in watts. For example:
- A 100-watt light bulb uses 100 watts.
- A typical desktop computer uses 65 watts.
- A central air conditioner uses about 3500 watts.
If your device lists amps instead of watts, then just multiply the amps times the voltage to get the watts. For example:
2.5 amps x 120 volts = 300 watts
Watt-hours - To know how much energy you're using you have to consider how long you run your appliances. When you run a 1-watt appliance for an hour, this is a watt-hour. It is abbreviated Wh. For example:
- One 100-watt light bulb on for an hour is 100 watt-hours (100 Wh)
- One 100-watt light bulb on for five hours is 500 Wh
- Five 100-watt light bulbs on for an hour is 500 Wh
Kilowatt-hours - 1,000 watt-hours is a kilowatt-hour (kWh). For example:
- One 100-watt light bulb on for an hour, is 0.1 kWh (100/1000)
- One 100-watt light bulb on for ten hours is 1 kWh (1 bulbs x 100W x 10h= 1000Wh = 1 kWh)
- Ten 100-watt light bulbs on for an hour, is 1 kWh (10 bulbs x 100W x 1h= 1000Wh = 1 kWh)
- Ten 50-watt light bulbs on for an hour, is 0.5 kWh
- Ten 100-watt light bulbs on for 1/2 an hour, is 0.5 kWh
- Running a 3500-watt air conditioner for an hour is 3.5 kWh.
Take a moment to understand the difference between kilowatts and kilowatt-hours. The former is the rate of power at any instant. The latter is the amount of energy used A light bulb doesn't use 60 watts in an hour, it uses 60 watt-hours in an hour.
The "-hours" part is important. Without it we'd have no idea what period of time we were talking about. If you ever see a reference without the amount of time specified, it's almost certainly per hour.
Vertical versus Horizontal Turbines
Advantages of vertical axis wind turbines (VAWTs)
- Easier to maintain because most of their moving parts are located nearer to the ground. This is due to the vertical wind turbines shape. The airfoils or rotor blades are connected by arms to a shaft that sits on a bearing and drives a generator below.
- As the rotor blades are vertical, a yaw device is not needed, reducing the need for this bearing and its cost and efficiency loss when tracking wind changes.
- Vertical wind turbines have a higher airfoil pitch angle, giving improved aerodynamics while decreasing drag at low and high pressures.
- Mesas, hilltops, ridgelines and passes can have higher and more powerful winds near the ground than up high because of the speed up effect of winds moving up a slope or funneling into a pass combining with the winds moving directly into the site. In these places, VAWTs placed close to the ground can produce more power than HAWTs placed higher up.
- Low installation height is useful where laws do not permit structures to be placed high.
- Smaller VAWTs, particularly modular designs which are shipped as kits and installed onsite, can be much easier to transport and install.
- May not need a free standing tower so is much less expensive and stronger in high winds that are close to the ground.
- Usually have a lower Tip-Speed ratio (particularly Savonious rotors) so less likely to break in high winds
- Ability to utilize wind from any direction without having to pitch or yaw and adjust to changes. No loss of efficiency or power collection due to wind direction change.
- Doesn’t have to shut down in high wind speeds. HAWTs which must shut down at high speeds cannot utilize the most powerful part of the wind regime, resulting in significant annual overall output decreases. Additionally, many HAWT inverters must draw grid power to re- activate after shutting down, contributing to significant annual parasitic losses over the course of a year.
Disadvantages of vertical wind turbines
- Most traditional VAWTs produce energy at only 50% of the efficiency of HAWTs in large part because of the additional drag that they have as their blades rotate into the wind. This can be overcome by using structures to funnel more and align the wind into the rotor (e.g. "stators") or the "vortex" effect of placing straight bladed VAWTs closely together. Modifications to the Helix design increases efficiency significantly, and Helix Wind turbines are only 6-7% less efficient that the most efficient HAWTs.
- There may be a height limitation to how tall a vertical wind turbine can be built and how much swept area it can have.
- A VAWT that uses guyed wires to hold it in place puts stress on the bottom bearing as all the weight of the rotor is on the bearing. Guyed wires attached to the top bearing increase downward thrust in wind gusts. Solving this problem requires a superstructure to hold a top bearing in place to eliminate the downward thrusts of gust events in guyed wired models.
Advantages of horizontal wind turbines
- Blades are to the side of the turbine's center of gravity, helping stability.
- Ability to wing warp, which gives the turbine blades the best angle of attack. Allowing the angle of attack to be remotely adjusted gives greater control, so the turbine collects the maximum amount of wind energy for the time of day and season.
- Ability to pitch the rotor blades in a storm, to minimize damage.
- Tall tower allows access to stronger wind in sites with wind shear. In some wind shear sites, every ten meters up, the wind speed can increase by 20% and the power output by 34%.
- Can be sited in forests above the tree line.
- May be self- starting.
Disadvantages of horizontal wind turbines
- HAWTs have difficulty operating in near ground, turbulent winds because their yaw and blade bearing need smoother, more laminar wind flows.
- Downwind variants suffer from fatigue and structural failure caused by turbulence.
Q: What are the dimensions?
A: Skystream turbines measure 12’ in diameter.
Helix wind turbines currently come in two sizes, the S322 and the S594. The S322 stands about 10 feet tall and 4 feet in diameter (3.2m x 1.2m). The S594 stands about 20 feet tall and 4 feet in diameter (6.4m x 1.2m).
Q: How tall is the mounting pole?
A: The mounting poles can vary in size from as small as 10’to as high as 90’ tall plus the height of the turbine.
The mounting pole for the Skystream is made of galvanized steel.
The Helix wind mounting pole is made of white epoxy coated steel.
Q: What are rotor startup/shutdown speeds?
A: These low speed turbines will start generating power at a little over 3.5 m/s (8 mph). They are self-starting and require no power or input to spin up. They do not need over speed control because of their design and will continue to output power as wind increases up to 50 mph. The units will continue to spin with no damage to the system in winds as high as 80 mph (this is a sustained speed, they can withstand gusts up to 125 mph), however no additional electricity will be generated above maximum output at 35 mph due to restrictions on the inverter.
Q: Is it safe for Birds and Bats?
A: Helix Wind turbines are completely safe for wildlife because they spin at much lower speeds than horizontal turbines and appear as a solid mass rather than a sharp blurring blade that a bird or bat cannot see or detect.
Q: Does the turbine make noise?
A: The designs of both the Helix Wind and Skystream turbines are nearly silent because they operate with tip speeds close to the wind velocity. This dynamic is similar to the wind blowing around any stationary object such as a tree or house. Conventional (horizontal) wind turbines spin at up to 10 times the wind speed which causes the whistling sound that can be heard around them.
Q: What are the mass & loadings?
A: The Helix wind S322 weighs approximately 310lbs.
The Helix S594 weighs approximately 1100lbs.
The Skystream 3.7 weighs approximately 170lbs.
Each 5 feet of tower pole weighs approximately 200 lbs.
*Weights excluding pole.
Q: How close can these turbines be mounted to each other?
A: The distance between turbines depends on each individual site. Some locations with strong, consistent prevailing winds can have adjacent turbines 6 feet apart. Other settings might require them to be 30 feet apart to minimize shadowing and a reduction in power output. The optimal layout places consecutive turbines in a line perpendicular to the prevailing wind.
Q: Can I sell electricity to the grid?
A: The laws/regulations vary quite a bit between jurisdictions, and there is a physics component to be careful of. There is a concept called “net metering” where customers connected to the Distribution system (as opposed to High Voltage customers) can net off the electricity they produce but not below zero. In other words, customers cannot actually sell surplus to the grid from home generation. The regulations that require electric utilities to buy tend to apply to customers directly connected to the high voltage. Most radial systems (i.e., distribution grids) are not designed to have injections of power at the lowest transformer levels. If the surplus power cannot be taken up by the other homes / businesses connected to the same transformer, then the transformer has to be replaced with a two way one, in order to step up power back to the voltage that runs inter-transformer. So there is a physics reason for this prohibition, not just utility policy.
Q: What safety features are there?
A: The Skystream 3.7 is constructed of a powder coated cast aluminum chassis with fiberglass reinforced blades. The advanced blade and vibration technology assures Skystream always produces energy efficiently and quietly. Redundant safety features protect Skystream from high winds without the need for mechanical overrides. The Skystream uses an electronic stall regulation braking system with redundant relay switch control.
The Helix Wind is constructed of high strength aluminum and stainless steel for a lifetime of use in extreme environments. The interlocking blade structure provides redundant load paths making a highly damage tolerant unit. The unit has an emergency brake for user initiated shutdown. Under normal expected conditions there is no need to stop the turbine; it will safely operate in 50 mph winds.
A: Does it have accreditation?
Q: The Skystream is fully accredited and it carries the UL listing.
The Helix wind Grid-Tie Inverter has CE marking and is currently undergoing evaluation for UL and CUL listing. The turbine and generator assembly is currently being tested for UL listing. With UL listing the Helix Wind is eligible for rebates under all state Renewable Energy Programs.
Q: How do I calculate my investment payback?
A: Unfortunately, accurately calculating the payback on your wind turbine investment is not as simple as it might seem. Wind turbine performance depends on a variety of factors including wind speed, tower height, wind shear, turbulence, local tree and building placement and air density. We’re happy to perform a custom analysis and estimate of the payback on your investment with a feasibility study. Contact us for additional information on this service.
Q: What are the economics of Small Wind?
A: Although small wind systems involve a significant initial investment, they can be competitive with conventional energy sources when you account for a lifetime of reduced or altogether avoided utility costs, especially considering escalating fuel costs.
The cost of buying and installing a small wind energy system typically ranges from about $5,500-7,000 per kilowatt for a grid-connected installation, less than half the cost of a similar solar electric system. The length of the payback period (or, the time it takes to "break even") depends on the system you choose, the wind resource at your site, your power provider’s electricity rates, and financing and incentives available. Small wind owners with strong average wind speeds who can take advantage of rebate programs can usually recoup their investments in as little as 6 years.
Many states have rebate or tax credit programs in place to encourage small wind and other renewable energy applications. AWEA's state-by-state pages provide information specific to buying and installing a small wind turbine in each of several U.S. states, including the availability of net metering, local or state incentive programs, and utility incentives.
The cost of a wind system has two components: initial installation costs and operating expenses. Installation costs include the purchase price of the complete system (including tower, wiring, utility interconnection or battery storage equipment, power conditioning unit, etc.) plus delivery and permitting costs, installation charges, professional fees and taxes.
A Good Investment for Windy Landowners with High Bills
A 2.5 kW grid-connected residential scale system generally costs between $15-20,000 complete with installation. A 5-kW grid-connected residential-scale system generally costs $20-25,000 to complete with installation. The best candidates for these systems are homes and businesses with at least a half acre of property, a Class 3 or better wind resource, and utility bills averaging $100 per month or more. If a net metering arrangement is available from the utility, most of the power generated by a grid-connected system can be valued at the retail rate of electricity, reducing the amount of time it takes for a system to pay for itself.
With the government tax credit small wind system owners with strong wind resources can recoup their initial investment in as little as 6 years, and enjoy essentially free electricity for the remainder of the system's 20-30 year useful life. Such a wind energy system can be an excellent, low-risk investment.
Smaller Systems Can Offset Electricity Costs, Provide Independence
Smaller wind energy systems also can be used to offset electricity costs, or to independently power specific applications such as water pumps or recreational vehicle lights and appliances.
Remote systems may require operating battery storage. Individual batteries cost from $150 to $300 for a heavy- duty, 12 volt, 220 amp-hour, and deep-cycle type. Larger capacity batteries, those with higher amp-hour ratings, cost more. A 110-volt, 220 amp-hour battery storage system, which includes a charge controller, costs at least $2,000.
Off-Grid Systems Can Be the Least-Cost Option for Electricity
The cost of extending the utility grid to a new home location can be significant, sometimes as high as $20,000 -$30,000 for a distance of only one-quarter of a mile. For the same initial investment, a utility-independent renewable energy system can be installed that will meet the electricity needs of an energy-efficient home. Such a system will typically include a combination of a wind turbine, photovoltaics, batteries, an inverter, and a back-up generator. These systems can be cost-effective on a first-cost basis alone, not to mention the avoidance of monthly utility bills for years to come.