Many people elect to install their own turbines.
Before attempting to install your wind turbine, ask yourself the following questions:. If you answered no to any of the above questions, you should probably hire a system integrator or installer. Contact the manufacturer for help or call your state energy office and local utility for a list of local system installers. A credible installer may be able to provide many services such as permitting, obtaining interconnection approval, etc.
Find out if the installer is a licensed electrician. Ask for references and check them. You may also want to check with the Better Business Bureau. Turbine and tower manufacturers should provide their own operations and maintenance plan; however, turbine owners should be aware that all rotating equipment will require some maintenance.
Many turbines require periodic lubrication, oil changes, and replacement of wear surfaces such as brake pads. The machines should be checked for corrosion and the guy wires for proper tension. In addition, you should check for and replace any worn leading edge tape on the blades, if appropriate. After 10 years, the blades or bearings may need to be replaced, but with proper installation and maintenance, the machine should last 20 years or longer. Every turbine should include an owner's manual or operations manual to provide the consumer with scheduled and unscheduled maintenance information as well as other unique product information.
Scheduled maintenance guidelines should be followed. If you do not have the expertise to maintain the machine, ask whether your installer provides a service and maintenance program. Notice that the wind speed V has an exponent of 3 applied to it. This means that even a small increase in wind speed results in a large increase in power. That is why a taller tower will increase the productivity of any wind turbine by giving it access to higher wind speeds.
The rotor-swept area A is important because the rotor captures the wind energy. So the larger the rotor, the more energy it can capture. A density correction should be made for higher elevations as shown in the Air Density Change with Elevation graph. A correction for temperature is typically not needed for predicting the long-term performance of a wind turbine. Although the calculation of wind power illustrates important features about wind turbines, the best measure of wind turbine performance is annual energy output.
The difference between power and energy is that power kilowatts [kW] is the rate at which electricity is consumed while energy kilowatt-hours [kWh] is the quantity consumed.
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They will use a calculation based on the particular wind turbine power curve, the average annual wind speed at your site, the height of the tower that you plan to use, micro-siting characteristics of your site and, if available, the frequency distribution of the wind an estimate of the number of hours that the wind will blow at each speed during an average year. They should also adjust this calculation for the elevation of your site.
To get a preliminary estimate of the performance of a particular wind turbine, use the formula below. The Wind Energy Payback Period Workbook is a Microsoft Excel spreadsheet tool that can help you analyze the economics of a small wind electric system and decide whether wind energy will work for you. It asks you to provide information about how you will finance the system, the characteristics of your site, and the properties of the system you're considering.
It then provides you with a simple payback estimation assumes no increase in electricity rates in years. If the number of years required to regain your capital investment is greater than or almost equal to the life of the system, then wind energy will not be practical for you. Is the wind resource at your site good enough to justify your investment in a small wind turbine system? That is a key question and not always easily answered.
The wind resource can vary significantly over an area of just a few miles because of local terrain influences on the wind flow. Yet, there are steps you can take to answer the above question. The highest average wind speeds in the United States are generally found along seacoasts, on ridgelines, and on the Great Plains;  however, many areas have wind resources strong enough to make a small wind turbine project economically feasible.
Although there may be many methodologies for understanding the wind resource at a specific location, gathering on-site, measured wind data is typically preferred. A Pika Energy small wind turbine in Gorham, Maine. Prior to conducting an on-site measurement campaign, some small wind project developers use state wind maps to conservatively estimate the wind resource at turbine hub height.
While these maps can provide a general indication of good or poor wind resources, they do not provide a resolution high enough to identify local site features. State wind maps cannot include information on complex terrain, ground cover, wind speed distribution, direction distribution, turbulence intensity, and other local effects. Purchased maps or services can often provide higher resolution and more flexibility with zooming, orientation, and additional features.
Pay attention to a map's height above ground as it relates to the potential project's tower height. Adjusting the wind speed for the height difference between the map and the turbine height adds a potential source of error depending on the wind shear exponent that is selected, and the greater the height difference the greater the potential error.
Therefore, for small wind generator applications, to m wind maps are far more useful than , , , or m wind maps. It is also important to understand the resolution of the wind map or model-generated data set. If the resolution is lower than the terrain features, adjustments will be needed to account for local terrain effects. Local airport or weather stations can offer local wind data, but these data may be less reliable than actual site data.
If airport data typically recorded at 30 ft or 10 m above ground or weather station data typically recorded at 5 to 20 ft above ground are used, inquire not only about the site's current equipment and location but also if it is historically consistent with the data collection equipment and siting. Equipment at these sites is not primarily intended for wind resource assessment, so it may not be positioned at an appropriate height or in a location free of obstructions.
Unfortunately, airport and weather stations are usually far from the site of interest, with considerably different orography, tree cover, and monitoring height, making these data of questionable usefulness. Given the expertise required to effectively establish and correlate wind resource data, the data provided by airport and weather stations may only provide a rough screening assessment. The National Climatic Data Center collects data from airports in the United States and makes wind data summaries available for purchase.
Another useful indirect measurement of the wind resource is the observation of an area's vegetation. Trees, especially conifers or evergreens, can be permanently deformed by strong winds. This deformity, known as "flagging," has been used to estimate the average wind speed for an area. Flagging, the effect of strong winds on area vegetation, can help determine area wind speeds.
Small wind site assessors can help you determine whether you have a good wind resource on your site. State or utility incentive programs may be able to refer you to site assessors with training in assessing the wind resource at specific sites. Computer programs that estimate the wind resource at a particular site given specific obstacles are also available. Site assessors and computer programs can help to refine the estimates provided on wind resource maps.
On-site data measurement adds a new layer of confidence to the techniques discussed above, but with substantial additional costs, effort, and time, especially when the preferred methodology is to match turbine hub height and collect data for a minimum of 1 year. Obtaining several years of data is better, or 1 year that can be referenced to a longer-term data set if there is good correlation with the on-site data. A number of small, affordable wind data collection systems are available for on-site measurement and are best run for at least 1 year.
These systems include anemometers, wind vanes, and temperature sensors that are mounted as close to hub height as possible. Calculating the wind shear exponent requires collecting data at two different heights. Having wind shear data is essential for conducting an accurate analysis of the cost versus benefits of taller towers. In addition, analysis must be performed to determine wind speed averages and extremes, wind distribution, Weibull parameters, the wind direction rose, turbulence intensity, vertical wind shear exponent, and associated uncertainties. Finally, if there is a small wind turbine system in your area, you may be able to obtain information on the annual output of the system and also wind speed data if available.
The farther you place your wind turbine from obstacles such as buildings or trees, the less turbulence you will encounter. A proper site assessment is a detailed process that includes wind resource assessment and the evaluation of site characteristics. With this in mind, you may wish to consider hiring an experienced small wind site assessor who can determine your property's optimal turbine location. If the surrounding area of a potential site is not relatively flat for several miles, then an evaluation of the main topographic features is necessary, both nearby macro siting and at the proposed turbine site micro siting.
The topographical evaluation should include shape, height, length, width, and distance and direction away from the proposed turbine site of any landforms. Owners of projects located near complex terrain should take care in selecting the installation site. Landforms or orography can influence wind speed, which affects the amount of electricity that a wind turbine can generate. Elevated areas not only experience increased wind speeds because of their increased height in the wind profile but also may cause local acceleration of the wind speed, depending on the size and shape of the landform.
If you site your wind turbine on the top of or on the windy side of a hill, for example, you will have more access to prevailing winds than in a gully or on the leeward sheltered side of a hill on the same property. Other elevated landforms bluffs, cliffs can create turbulence, including back eddies, as the wind passes up and over them. Siting the tower to avoid the zones of turbulence created by the landform is critical.
Turbulence intensity is a major issue for small turbines because of their tower height and location around "ground clutter. Varied wind resources can exist within the same property. In addition to measuring or finding the annual wind speeds, you need to know about the prevailing directions of the wind at your site. Knowing the prevailing wind direction s is essential to determining the impact of obstacles and landforms when seeking the best available site location and estimating the wind resource at that location. To help with this process, small wind site assessors typically develop a wind rose, which shows the wind direction distributions of a given area.
Wind roses can be generated based on annual average wind speeds, or by season, month, or even time of day as needed. In addition to geologic formations, you need to consider existing obstacles such as trees, houses, and sheds, and you need to plan for future obstructions such as new buildings or trees that have not reached their full height.
Whether the system is stand-alone or grid-connected, you also need to consider the length of the wire run between the turbine and the load house, batteries, water pumps, etc. A substantial amount of electricity can be lost as a result of the wire resistance—the longer the wire run, the more electricity is lost.
Using more or larger wire will also increase your installation cost. Your wire run losses are greater when you have direct current DC instead of alternating current AC. So, if you have a long wire run, it is advisable to invert DC to AC. You may wish to consider hiring an experienced small wind site assessor who can determine where the turbine should be located on your property.
While there have been instances of wind turbines mounted on rooftops, it should be noted that all wind turbines vibrate and transmit the vibration to the structure on which they are mounted. This can lead to noise problems within the building. Also, the wind resource on the rooftop is in an area of increased turbulence, which can shorten the life of the turbine and reduce energy production.
Additional costs related to mitigating these concerns, combined with the fact that they produce less power, make rooftop-mounted wind turbines less cost-effective than small wind systems that are installed on a tower connected to the ground. Small wind energy systems can be connected to the electricity distribution system. A grid-connected wind turbine can reduce your consumption of utility-supplied electricity for lighting, appliances, and electric heat.
If the turbine cannot deliver the amount of energy you need, the utility makes up the difference.
When the wind system produces more electricity than the household requires, the excess is sent or sold to the utility. These arrangements with the utility company are typically called net metering or net billing, and they address the value of the electricity sold or net excess generation, the time period for valuing the electricity typically annually or monthly , and any other contractual requirements with the utility. A grid-connected wind turbine can reduce your consumption of utility-supplied electricity.
However, you should contact your utility before purchasing a wind turbine system and connecting to their distribution lines to address any power quality and safety concerns. Your utility can provide you with a list of requirements for connecting your system to the grid. AWEA contributed much of the following information. Southwest Windpower's 1. Net metering programs are designed to allow the electric meters of customers with generating facilities to "turn backwards" when their generators are producing more energy than the customers' demand.
Net metering allows customers to use their generation to offset their consumption over the entire billing period, not just instantaneously. This offset would enable customers with generating facilities to receive retail prices for more of the electricity they generate. Net metering varies by state and by utility company, depending on whether net metering was legislated or directed by the Public Utility Commission. If the net metering requirements define NEG on a monthly basis, consumers can only receive credit for their excess that month.
Most of North America sees more wind in the winter than in the summer. For people using wind energy to displace a large load in the summer like air conditioning or irrigation water pumping , having an annual NEG credit allows them to produce NEG in the winter and receive credits in the summer. Whether or not your wind turbine is connected to the utility grid, the installation and operation of the wind turbine is probably subject to the electrical codes that your local city or county government, or in some instances your state government, has in place.
The government's principal concern is the safety of the facility, so these code requirements emphasize proper wiring and installation and the use of components that have been certified for fire and electrical safety by approved testing laboratories, such as Underwriters Laboratories. The latest version of the NEC includes sections specific to the installation of small wind energy facilities.
It is available for purchase online at the National Fire Protection Association website  and can also be found at most local libraries. If your wind turbine is connected to the local utility grid so that any of the power produced by your wind turbine is delivered to the grid, then your utility also has legitimate concerns about safety and power quality that need to be addressed.
The utility's principal concern is that your wind turbine automatically stops delivering any electricity to its power lines during a power outage.
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Otherwise line workers and the public, thinking that the line is "dead," might not take normal precautions and might be hurt or even killed by the power from your turbine. Another concern among utilities is whether the power from your facility synchronizes properly with the utility grid and it matches the utility's power in terms of voltage, frequency, and power quality. A few years ago, some state governments started developing new standardized interconnection requirements for small renewable energy generating facilities including wind turbines.
In most cases, the new requirements are based on consensus-based standards and testing procedures developed by independent third-party authorities, such as the Institute of Electrical and Electronic Engineers IEEE and Underwriters Laboratories. Utility companies will typically require compliance with IEEE , which addresses electrical safety requirements for wind turbine systems. Some utilities may require appropriate electrical listing before allowing interconnection of the wind system.
In most cases, it is quite advantageous to interconnect a small turbine with the customer's utility service, thereby using the utility for backup power to cover the variability of the turbine's energy production as well as storage of excess energy. Such interconnection typically requires utility permission, which is usually in the form of an interconnection agreement. This agreement will address metering and billing arrangements with the utility and may include requirements for additional safety equipment or procedures, protection devices, and inspections.
In states that have retail competition for electricity service e. Usually these agreements are written by the utility or the electricity provider. In the case of private investor-owned utilities, the terms and conditions in these agreements must be reviewed and approved by state regulatory authorities. Other utilities consider the insurance requirements excessive and unduly burdensome, making wind energy uneconomic. In seven states California, Georgia, Maryland, Nevada, Oklahoma, Oregon, and Washington , laws or regulatory authorities prohibit utilities from imposing any insurance requirements on small wind systems that qualify for net metering.
In at least two other states Idaho, Virginia , regulatory authorities have allowed utilities to impose insurance requirements but have reduced the required coverage amounts to levels consistent with conventional residential or commercial insurance policies e.
If your insurance amounts seem excessive, you can ask for a reconsideration from regulatory authorities in the case of private investor-owned utilities or the utility's governing board in the case of publicly owned utilities. An indemnity is an agreement between two parties in which one agrees to secure the other against loss or damage arising from some act or some assumed responsibility. In the context of customer-owned generating facilities, utilities often want customers to indemnify them for any potential liability arising from the operation of the customer's generating facility.
Although the basic principle is sound—utilities should not be held responsible for property damage or personal injury attributable to someone else—indemnity provisions should not favor the utility but should be fair to both parties. Look for language that says, "each party shall indemnify the other.
Customer charges can take a variety of forms, including interconnection charges, metering charges, and standby charges. You should not hesitate to question any charges that seem inappropriate to you. Hybrid wind energy systems can provide reliable off-grid power for homes, farms, or even entire communities a co-housing project, for example that are far from the nearest utility lines. According to many renewable energy experts, a "hybrid" system that combines wind and photovoltaic PV technologies offers several advantages over either single system.
In much of the United States, wind speeds are low in the summer when the sun shines brightest and longest. The wind is strong in the winter when less sunlight is available and may be stronger at night compared to the day. Because the peak operating times for wind and PV occur at different times of the day and year, hybrid systems are more likely to produce power when you need it. If the batteries run low, the engine-generator can provide power and recharge the batteries. Adding an engine-generator makes the system more complex, but modern electronic controllers can operate these systems automatically.
An engine-generator can also reduce the size of the other components needed for the system.
Keep in mind that the storage capacity must be large enough to supply electrical needs during non-charging periods. Battery banks are typically sized to supply the electric load for 1 to 3 days. Airfoil —The shape of the blade cross-section, which for most modern horizontal-axis wind turbines is designed to enhance the lift and improve turbine performance. Alternator —An electric generator for producing alternating current. See also generator. Ambient —Of the surrounding area or environment; completely surrounding; encompassing.
Used to distinguish environmental conditions, e.
Ampere-hour —A unit for the quantity of electricity obtained by integrating current flow in amperes over the time in hours for its flow; used as a measure of battery capacity. Authority Having Jurisdiction AHJ —The building authority for the area, generally a city or county building department, including its inspectors. Availability —A measure of the ability of a wind turbine to make power, regardless of environmental conditions.
Generally defined as the time in a period when a turbine is able to make power, expressed as a percentage. Beaufort scale —A scale of wind forces, described by name and range of velocity, and classified from force 0 to 12, with an extension to The initial Francis Beaufort wind force scale of 13 classes 0 to 12 did not reference wind speed numbers but related qualitative wind conditions to effects on the sails of a frigate, then the main ship of the Royal Navy, from "just sufficient to give steerage" to "that which no canvas sails could withstand.
See also net metering. This is the maximum amount of power that can be captured from the wind.
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In reality, this limit is never achived because of drag, electrical losses, and mechanical inefficiencies. See also Cp. Blades —The aerodynamic surface that catches the wind. See also wing, airfoil, rotor. Certification —A process by which small wind turbines kW and under can be certified by an independent certification body to meet or exceed the performance and durability requirements of the American Wind Energy Association AWEA Standard. Cp —Power coefficient; the ratio of the power extracted from the wind by a wind turbine relative to the power available in the wind.
See also Betz limit. Cut-in wind speed —The wind speed at which a wind turbine begins to generate electricity. Cut-out wind speed —The wind speed at which a wind turbine ceases to generate electricity. Direct drive —A blade and generator configuration where the blades are connected directly to the electrical generating device so that one revolution of the rotor equates to one revolution of the electrical generating device. Displacement height —The height above ground level where wind speed is theoretically zero based on the effects of ground cover.
Distributed generation —Energy generation projects where electrical energy is generated primarily for on-site consumption. Term is applied for wind, solar, and non-renewable energy. Diurnal —Having a daily cycle or pattern. It may be useful to average many daily cycles of wind speed or wind energy production to understand a typical daily pattern, by month, season, or year. Downwind —On the opposite side from the direction from which the wind blows.
Drag —An aerodynamic force that acts in the direction of the airstream flowing over an airfoil. Dual-metering —Buying electricity from the utility and selling it to the utility with two different energy rates, typically retail buying and wholesale selling. Electric cost adjustment —An energy charge dollars per kilowatt-hour on a utility bill in addition to the standard rate in the tariff, which is associated with extra costs to purchase fuel, control emissions, construct transmission upgrades, and so on.
These various costs may be itemized or rolled into one electric cost adjustment rate. Sometimes referred to as fuel cost adjustment. Electric utility company —A company that engages in the generation, transmission, and distribution of electricity for sale, generally in a regulated market. Electric utilities may be investor owned, publicly owned, cooperatives, or nationalized entities. Energy curve —A diagram showing the annual energy production at different average wind speeds, typically assuming a Rayleigh wind distribution with a Weibull shape factor of 2.
Energy production —Energy is power exerted over time. Energy production is hence the energy produced in a specific period of time. Electrical energy is generally measured in kilowatt-hours kWh. See also power. Environmental conditions —Of or pertaining to ambient state of the environment. See also temperature, wind, humidity, corrosivity.
Flagging —The deformation of local vegetation toward one direction, indicating the prevailing wind direction and relative strength more formally called Krummholtz formation. Flagging is sometimes used with the Beaufort scale to generate an initial estimate of local site conditions. Note: flagging does not determine the wind resource, but is a confirming indicator of it.
For example, sometimes flagging is the result of sunlight availability, or trimming of tree branches near electrical lines. The assessor needs to understand when flagging is relevant, or when it is a confirming indicator of another condition at the site. Frequency distribution —A statistical function presenting the amount of time at each wind speed level for a given data set and location, usually in percent of time or hours per year. Furling —A passive protection for the turbine in which the rotor folds up or around the tail vane.
Gearbox —A compact, enclosed unit of gears or the like for the purpose of transferring force between machines or mechanisms, often with changes of torque and speed. In wind turbines, gearboxes are used to increase the low rotational speed of the turbine rotor to a higher speed required by many electrical generators.
Generator —A machine that converts mechanical energy to electricity. The mechanical power for an electric generator is usually obtained from a rotating shaft. In a wind turbine, the mechanical power comes from the wind causing the blades on a rotor to rotate. See also blade, rotor, stator, alternator. It may also be used to visualize the relationships between terrain, wind data, land-use boundaries, obstacles, and potential wind turbine locations.
Governor —A device used to limit the RPM of the rotor. Limiting RPM serves to reduce centrifugal forces acting on the wind turbine and rotor as well as limit the electrical output of the generating device. Governors can be electrical, also know as "dynamic braking," or mechanical. Mechanical governors can be "passive," using springs to pitch the blades out of their ideal orientation, or an offset rotor that pitches out of the wind, or "active" by electrically or hydraulically pitching blades out of their ideal orientation.
Grid —The utility distribution system. The network that connects electricity generators to electricity users. Grid-connected —Small wind energy systems that are connected to the electricity distribution system. These often require a power-conditioning unit that makes the turbine output electrically compatible with the utility grid.
See also inverter. Gross annual energy production —The amount of annual energy usually in kilowatt-hours estimated for a given wind turbine at a given location, before adjusting for losses see net annual energy production. Guyline —A guyline or guy wire supports guyed towers, which are the least expensive way to support a wind turbine. Guyed towers can consist of lattice sections, pipe, or tubing. Because the guy radius must be one-half to three-quarters of the tower height, guyed towers require more space to accommodate them than monopole or self-standing lattice towers.
Horizontal-axis wind turbine HAWT —A wind turbine with a rotor axis that lies in or close to a horizontal plane. Often called a "propeller-style" wind turbine. Hub —That component of a wind turbine to which the blades are affixed. See also rotor, blade. Induction generator —An asynchronous AC motor designed for use as a generator. Generates electricity by being spun faster than the motor's standard "synchronous" speed. Must be connected to an already-powered circuit to function i.
Interannual variability —The variation from year to year in average wind speed, distribution, and patterns. Skickas inom vardagar. Small wind turbines utilize wind energy to produce power with rated capacities of kilowatts or less. With this increasingly popular technology, individual businesses, farms, and homes can generate their own electricity and cut their energy bills , while generating power in an environmentally sound manner. The challenges facing the engineers who are tasked with planning and developing these small wind systems are multifaceted, from choosing the best site and accurately estimating power output, to obtaining proper permitting and troubleshooting operational inefficiencies.
Optimization of project development for small wind applications is a necessity. Small Wind: Planning and Building Successful Installations provides a cohesive guide to achieving successful small wind installations from an informed expert. It is a comprehensive information resource from one of the world's most experienced small wind professionals, covering all the key issues for small wind system development, from site and machine selection to international standards compliance. Establishes technical guidelines for the growing number of engineers called upon to plan small wind projects Identifies and explains the critical issues for small wind installations, including siting, turbine choice, applications and permitting, economics, load management, and grid integration Examples from real projects demonstrate key considerations for success, complete with template spreadsheets and measurements needed to support project planning efforts Includes reports on the most commonly used turbines and designs and synthesizes and clarifies relevant wind industry documentation, saving readers endless hours of research.
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