Residential Wind Energy :
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Would you like to rely less on the power grid?
Do you want to be more "environment-friendly" with a nice little windmill spinning quietly in the breeze generating extra electricity outside your house?
The thought is exciting...But where do you start?
People used residential wind energy for centuries to mechanically grind grains and pump water. But, it wasn't until Charles F. Brush built The Brush Machine (the first wind generator) in Cleveland, Ohio, in 1888 that wind was actually used for the first time for generating usable electric power.
Things have certainly improved since then!
Like most of us, you have probably gotten used to buying power from your utility company (The Grid) and you might tend to get a little worried at first at the notion of putting a large windmill up outside your house. But, you would still like to at least try it - And which of us wouldn't like to?
Several questions may come to mind if you've never used residential wind energy before (since this is a relatively new concept for most of us anyway):
- How much is this going to cost me?
- How long will it take to set this up and pay for itself?
- What's involved in a setup like this?
- How long will a system like this last?
- What types of city, state, and federal certifications/licenses do I have to have or meet? And is it allowed where I live?
These are understandable questions, but well worth getting the answers to. Especially with the amount of money you can save by installing a smaller (less than 100 kilowatt) residential wind energy generator onto your home system. The overall savings can be significant!
And if you store this power in batteries or produce more than you use, in most cases you can even sell it back to the utility company for a discount or additional profit.
We have some experience in setting up our own wind generators, and we want to help you answer these questions and any others you might have before you get started...
Where Do I Start?
The first question you will need to answer to set up a residential wind energy turbine system is "Where do I start?"
Following are some questions to ask yourself before deciding to use residential wind energy:
- How Much Power Do I Use/Need?
- What Size Windmill Do I Need?
- Do I Want Off-Grid, Interconnected, or Intertie?
- What About Safety and Location?
- 2 or 3 blades - It has been argued by many people as to what number of blades are the "perfect" number for a wind generator. After carefully testing multiple units over several years, it has been found and proven that a 3 bladed unit has a better balance and therefore can last longer than a 2 blade (less wear and tear from imbalance over the long term).
- Overspeed Control - A turbine needs to be able to control its own speed in high winds to prevent it from breaking or overheating. Most home units are fitted with a spring-loaded hinge that allows the blades to bend away from the directional (or what is known as a furling tail) during higher winds to prevent "overspeed". Some more expensive units will have a braking system (but this is usually only found on the larger commercial size turbines - not on smaller home units)
- Type of Tower - You need to decide what type of tower you want to use for your wind turbine. There are 3 basic types: free-standing lattice, free-standing pole, and a guyed mast (see diagram below). Which one you choose is dependent on how high your turbine needs to be placed, what ordinances you need to comply with, and ease of getting to the unit for any repairs or maintenance (Will you have to climb up the tower? Or can you lower the unit to the ground?, etc.)
- Off-The-Grid - If you want to use enough wind power to no longer have to depend on the grid, you will need to decide what to do if there is no wind - (For Example: Will you store power in batteries? Will you supplement wind power with solar or some other form? etc.)
- Interconnected or Utility Intertie - Prior to 1978, electric companies had no interest in furthering more independence from them by allowing wind or solar power "inter-connected" with their systems. But, in 1978 the passage of PURPA (the Public Utility Regulatory Policies Act) allowed inter-connectivity for the first time.
Because of this, you can now use wind power alongside your utility company's power - and they can even credit you or pay you for extra energy YOU produce! (This also allows for backup power supply for you if your wind system is down or not producing electricity)
**** It is recommended that you contact your utility company prior to installing this type of setup and make sure all details of the setup are understood between both of you before proceeding.
How Much Power Do I Use?
To decide how much power you use in your home or office, you will need to look at the following tables for some of the most common appliances and their watt ratings:
| AC APPLIANCES | ||||
|---|---|---|---|---|
| Appliance Toaster Oven VCR Well Pump Sewing Machine Satellite TV Refrigerator/freezer Vacuum Circular Saw Hair Dryer Jigsaw Computer | Watts 1500 35 800 87 50 460 1125 1500 1500 300 250 | Appliance Laptop Monitor 42” TV DVD Drill Microwave oven Compact fluorescent Battery Charger Blender/mixer Belt Sander | Watts 80 60 200 14 800 1245 13 25 350 800 | |
| DC APPLIANCES | ||||
|---|---|---|---|---|
| Appliances Cell Phone Motor (small) DC Refrigerator Radio Stereo Water Pump VCR 14” Color TV Battery Charger Inverter Standby Halogen Light | Watts 4 65 13 15 30 50 15 75 7 5 20 | |||
Now, to figure the total power you are using, do this: The rate of power that flows through a wire is known as a Kilowatt Hour (KWH). This is what shows on your monthly power bill and is how you measure power used.
For Example: If you turned on a 200 watt 42" TV for 5 hours, the rate of power used would be 200 X 5 = 1,000 watt-hours or 1 Kilowatt hour (kilo means 1000).
**** You can also look at your monthly power bill from the last year and get the average total power used for each month.
What Size Windmill Do I Need?
Though a lot of people cannot get around it (and no matter how much of a "bummer" it is for us to accept it), the fact remains that where you live or wish to set up your residential wind energy turbine will only have a certain average amount of wind in a given year. And that amount usually doesn't change much - if it ever changes.
It can be a little hard for some of us to accept this fact. But you wouldn't want to invest a lot of money and time in a wind system, only to find that it may not work for your needs because you're not in a good location with the right kind of average winds.
For the most part, the area covered by the blades of a windmill is the most important number you will need.
1.) Begin with the Power Equation: The power that can be derived from a wind generator can be found in the equation:
Power = In Watts
ρ = Air pressure at the level above sea level where the windmill blades are located (1.225 just above sea level)
A = Area covered by blades of the windmill (see below)
V = Velocity (Speed of the wind)
Now, we don't mean to get too mathematical here (And we hope we haven't put you to sleep yet). This equation is what everything else is fed into to determine (over a month or a year) how much power you can get from a windmill of a certain size.
2.) Find the AREA portion of the above equation: The A (Area) covered by the windmill in the above equation is determined by a second equation:
Π = 3.14
R = Radius of circle covered by blades...or 1/2 the width of the entire circle2
So, for a windmill that has blades 6 feet long (12ft circle) using the A (Area) in this equation back into the first "Power" equation in Step 1 (Power = 1/2ρAV3) we get:
AREA = 3.14 * 62 = 113.04 ft2
Plug that info into the Power Equation above along with wind velocity/speed (V) and you can figure the power output for a windmill of a certain size (in our example, we used a windmill with blades 6ft in length). It's also better to use averages for wind velocity over longer periods of time - say several months or a year.
**** Remember also that this is maximum performance in "near perfect" conditions (which seldom happen). In reality, you will only get about 30% of this maximum capability for most windmill units.
This is another "bummer" part of the whole thing, but it's something that has to be taken into consideration - as most devices have some loss for different reasons and are not always perfectly generating power. You also need to know what to realistically expect from your own setup without exaggerated (maximum) numbers.
Basics of Wind Turbine Technology
Small home wind turbines come in all sizes, shapes and colors and can present you with a somewhat confusing array of choices. The key is in understanding your specific needs.
Here are some of the things you need to consider when looking at wind turbines:
Do I Want Off-Grid,
Interconnected, or Intertie?
During the 1970s when oil prices began sky-rocketing the first time because of shortages, wind power began its real move into everyday life.
Many people began conceiving of a day when wind power was so widely used (especially in the United States) that every house and farm would have their own wind power - and we would all buy or provide power from each other much cheaper over an inter-connected network rather than from utility companies.
This vision has yet to come true, but manufacturers of wind turbines are still making these units almost as fast as they can to keep up with sales.
You will need to ultimately decide how you want to use residential wind energy:
Safety and Location
The greatest obstacles you will have to overcome to install and use a wind turbine are "Where can I put it?" and "How safe will it be?"
Some of the things that have to be considered when first installing a turbine are:
 | Tower Height - The height of your tower needs to be tall enough to get away from interference caused by buildings and trees, but yet be a height that you can safely tolerate if it happened to collapse and fall and yet still get good wind. You don't want it possibly causing damage if pieces of something fall off of it and you want it to clear other things (like your neighbor's yard or house) if it DOES fall. |
| Distance from House - The distance your turbine is from your house (and your neighbors) can be too close if it causes you or them too much noise when it is operating, but it can be too far if the electricity has to travel too far to get to your system for use (more distance = more resistance). |
| Safety - You are, after all, dealing with something electrical. Always remember that these units generate electricity when they are spinning and use caution around them and the battery systems that may be in place. |
Click Here to view a size and rating chart for the residential wind energy turbines we discovered are some of the most popular and reliable units currently available on the market today for you to purchase and use.
Paul Gipe also has an amazing residential wind energy book called
Wind Energy Basics. This is a book 100% focused on small and micro wind systems. While The Renewable Energy Handbook is my favorite renewable energy book...Paul's book is great for getting set up with your own home system easily and affordably.
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