Planning a Small Wind Project

There are many steps in putting together a small wind project. What follows is a basic outline of the major steps in planning a small wind project.

The process:

What is the motivation behind your wind project?

This is the first question one should ask themselves before undertaking a small wind installation.

Many like the idea of energy independence, while others wish to incorporate their energy consumption into their love of machines and technology. Some people chose to put up their own turbines for environmental reasons, because wind energy is a clean, emission free, renewable energy source. Whatever your motivation you should understand what is involved in owning your own wind generator as they are sophisticated pieces of machinery that will need periodic maintenance and can be fairly large investment.

Your motivation for planning a small wind project will affect your choice of equipment, the economics of your project, and how you choose to operate and maintain your small wind system.

At the beginning of planning your project keep the following questions in mind:

  • What will the energy be used for?
    Some people have off-grid systems where all of the energy used on the site must be generated there. Others will choose to connect their system to the utility's system and use the grid for backup energy when the wind does not blow. Others wish to sell energy back to the utility to provide supplemental income for their farm or business.
    Will the system offset some or all of the energy consumed on site? If this is the case, your state may have net metering laws which can help with the economics of your project but may limit the size of your system.
  • Do I want to sell the energy to the utility?
    If you want to sell most or all of your energy to the utility this will affect the scale and financing of your machine. Larger machines generally can produce energy at a lower cost than small machine and will improve the return on investment. If selling power to the utility and making money is a primary motivation, then you may want to consider investing in a Community wind project over a small wind system.
    Is cost of energy important to your project? Are your primary motivations environmental or energy independence?
    Cost of energy will greatly affect the components you choose. A general rule is that as system size increases the cost per installed kW will decrease, improving the economics of the project. If you are on a limited budget or want to size your system so that it matches up to your electricity consumption for an off grid system you will choose system components using a different set of assumptions.
  • What is the budget for your system?
    Budget is in many cases the limiting factor for small wind systems. Because the return on investment is generally low compared to commercial scale turbine the system must be able to fit within your family or businesses budget to make sure you can afford to make payments on any loans taken to finance the system.

Small Wind Economics

For a small wind system determining the payback of a project plays a large factor in determining if owning your own system makes sense for you. In order to do this you will need several pieces of information:

  • a reasonable estimate of the wind resource at your site
  • the height of the tower
  • the turbine model's power curve
  • the installed cost of the system
  • Annual hidden costs that include maintenance, added insurance, fees paid to the utility, etc.
  • The cost of energy at your site as well as historical electricity consumption on a monthly basis.
  • Information from your utility about system size limits, the net metering structure.
  • interest rate on loan for equipment purchased
  • information about grants and incentives available to you

Typically, for a small wind system, energy produced is used to offset a portion or all of the electricity at a site. Excess generation is then "stored" on the grid for times when the generator is not producing. At the end of the billing period the net excess generated or consumed is used to determine how much you owe the utility or the utility owes you. The rate and rules for compensation differ from state to state.

Once you determine how energy is compensated, the estimated production on a monthly basis and the installed and hidden costs of the turbine, the payback period can be determined by dividing the sum of the costs by the net energy produced times the rate compensated for energy.

# Years = (sum of installed costs and ongoing costs)/ [(energy produced) x (rate compensated for energy)]

This will yield the number of years it will take to pay off the machine. This calculation is called a simple payback because it does not take into account net present value, inflation, and escalation of energy costs over time. In most cases this method will be more conservative than a more involved analysis.

Knowing Your Wind Resource

The first step to designing your system is determining if you have enough wind to justify the expense of the system and the time and expense of operating and maintaining your equipment. Remember: a small turbine without enough wind is like a solar panel in the shade: it won't produce energy!

Generally, a site with an annual average wind speed of 12 miles per hour or greater does not need a detailed wind resource study to be performed. A site with an average wind resource of 10 miles per hour or less usually does not have enough wind to justify installing a turbine. A site that has an average wind speed between 10 and 12 miles per hour should have a wind resource assessment performed to determine if there is adequate wind to support a small wind turbine.

A good place to begin determining your wind resource is National Renewable Energy Laboratory's (NREL) wind resource maps. Download the map for your state and find the general area where your property is located. This will give you a fairly good sense of the average wind speed in your area with no expense. For more detailed information about determining if you have a good wind resource view the Department of Energy's Small Wind Electric Systems: a U.S. Consumer's Guide. State-specific consumer guides can also be found at the Department of Energy's Energy Efficiency and Renewable Energy website.

Wind speed data is also often available from local weather stations or airports, as well as the US Dept. of Commerce, National Climatic Center in Asheville, N.c. You can also do your own site analysis with an anemometer or totalizer and careful observation.

Placement

Installation of generators should be close to the battery bank to minimize line loss, and 20 feet higher than obstructions within 500 feet. The tower should be well grounded.

Choosing a turbine, tower and other equipment

A typical wind energy system consists of a turbine mounted on top of a tower and a controller consisting of power electronics which controls the power output of the turbine under various wind and grid conditions.

Typically a controller will come as part of a package with the turbine, making turbine and tower the major decisions in choosing your system.

There are more than several different turbine manufacturers with many models of turbines to choose from as well as several tower configurations that vary in erection difficulty.

Choosing a small wind turbine model

Wind turbines come in many different makes and models. Spending a little extra time while choosing a model will improve economics of your project as well as make it much more successful in the long run.

Before choosing a turbine you should figure out if the electricity produced will be consumed completely on site, if you want to sell excess energy back to the utility company or if you prefer to be off the grid. The turbine model you choose will be greatly affected by where the electricity will ultimately be used and what compensation you will receive from selling electricity back to the utility. If your facility will be net metered or off the grid a load analysis for your home should be done to determine your monthly electricity usage, for net-metering, or your peaking load and daily usage for off grid applications.

Turbine manufacturers have published power curves that estimate the monthly output for their turbines based on average wind speed at the site and the Rayleigh distribution of wind speeds around that average.

Remanufactured Turbines

Buyers should beware of used, refurbished, or remanufactured machines. Even though these machines may initially be less expensive that comparable new machines, the initial savings can be negated very quickly by costly repairs from a machine that is nearing the end of it's life time...

Choosing a Tower

Small wind system manufactures often give you several different tower options to best match the economic, maintenance and space needs of your project.

There are four basic types of tower options for home and farm sized turbines: tilt-up, guyed lattice, lattice and free standing

Choosing an installer for your project

Choosing an installer for your wind turbine and other related equipment is as important if not more so than choosing the equipment for your system. Before deciding on an installer ask the installer if you can contact other people he or she has done work for. Eco Depot USA will work with you as you design your equipment and work closely with the interconnecting utility to ensure that the process goes smoothly.

Eco Depot USA use's a licensed and bonded electrician. For complete information about what is required for electrical certification for an installer contact your utility.

Working with your utility

To have a successful grid connected project you have to work with the utility to make the interconnection go smoothly. Get the utility involved early in the process of planning. Many times your utility will have a dedicated contact for systems of this size range. They will also have technical interconnection standards for your equipment and special meters which may need to be installed at your service. You will also need to have a state electrical inspector sign off on your system before the utility will allow you to connect to the grid. The inspector will require that all electrical work, wiring and otherwise, be completed by a licensed and bonded electrician.

Zoning/Permitting

Before putting your project in the ground you will have to acquire the appropriate permits from your county zoning office or municipal zoning office. Many areas that have seen much wind energy development in recent years may have zoning ordinances designed specifically for smaller wind projects. If this is not the case you may have to obtain a special use permit from the county zoning board.

Having other small wind turbines in the area may make the process easier. However, you may have to be persistent with the process because zoning board members may associate your proposed project with its larger utility scale cousins.

The issues that you will have to address while going through the zoning process include:

Setbacks from property lines, structures, roads, river beds, etc.

Safety standards for tower and electrical equipment, including proper grounding of turbine and tower

Aesthetics of tower and turbine design

Noise

Interference with electro-magnetic telecommunications

 

 

Insurance

A small wind machine needs to carry insurance to protect the equipment, just like any other large investment you make. If a once in one hundred year storm destroys the machine, liability insurance is important to protect yourself, others and the interconnecting utility against unforeseen circumstances. Some states, such as Minnesota mandate that the machine have a certain amount of liability insurance, while in other states utilities set their own requirements for insurance.

Net Metering

Net metering is a way for you to connect your small wind turbine behind the meter at your home, business or farm. This system is designed to allow energy generated at your home farm or business to offset some or all of the electricity you use. If your generator is producing more electricity than you can consume the excess is sold back to the utility. The price that a project receives for the excess electricity varies from state to state and from utility to utility.

Net metering can be very helpful for the economics of a wind project because it allows a qualifying facility to receive retail rate for a portion or all of the electricity generated. Each state has different rules and regulations. To find out if net metering is available in your state, what systems qualify and how to take advantage of the programs visit the Database of State Incentives for Renewable Energy. 

Operations and Maintenance

In a good year at a good wind site, a small turbine might be running 6,000 hours over the course of a year. For comparison, this is about the same as driving your car 200,000 miles! Not surprisingly, your small turbine will last longer and perform better if maintenance is done regularly.

For most systems, you should plan to either tilt down the tower or climb the tower once a year to check for signs of unusual wear, tighten bolts, lubricate moving parts and perform other general maintenance. You should check with the manufacturer of your turbine for specific guidelines. 

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