Residential Wind Power Facts | Turbines and Towers
It seems like every week or so a new wind turbine model is brought to market. Even
more so now with the 30% energy tax credit for renewable energy systems that
expires in 2016. Taken together with state mandated tax credits, rebates, or grants
you can get a shiny new wind or solar powered system for as much as 50% off.
Before you choose a wind turbine and tower you have to decide how much of your
current power usage you want to replace. In order to do that you have to know how
many kWh (kilowatt hours) of electricity you consume annually. So get out a years
worth of electric bills, look at the meter reading section for kWh usage and add 'em all
If you're the average American household you consume between 9,000 and 12,000
kWh per year. And if you're planning on replacing let's say 9,000 kWh a year with wind
power you would need a 10k system costing upwards of $40,000 plus installation.
This might sound like a lot of money, but dollar for dollar you'd get 4 to 5 times more
energy than from a smaller 1.8K system costing around 13,000 - $18,000.
Large Home Wind Turbine Manufacturers 1,000+ kWh/month
Bergey BWC Excel Endurance X Series Jacobs 31-20
The output of any size generator is determined by the diameter (3 props), or length (2
props) of the rotor. The diameter, or length, determines the "swept area" of the rotor;
the larger the swept area, the more energy is generated. The rotors on large
generators are typically in the 20' range with a swept area of 300 - 400+ square feet
and generate 1,000+ kWh of power a month at 12 mph winds.
You can estimate the monthly power production for any turbine on this page by
inputting your local wind speed and the prop diameter into this calculator.
Medium Home Wind Turbines 500 kWh/month @ 12/mph
Small Home Wind Turbines Less than 500 kWh/month @ 12 mph
Bergey XL.1 Battery only system: Whisper 200
Wind Turbines Towers
Each manufacturer listed above also sells tower kits on their websites to complement
their generators. Many towers can be used interchangeably with other manufacturers
turbines but may require an adapter kit.
Tower heights start at 33' and range upwards of 100'. As tower heights increase, the
wind becomes faster and less turbulent. A 20 foot increase in tower height, from 60 to
80 feet for instance, can increase the output of your wind turbine by more than 20%.
The general rule of thumb for placing wind turbines is that the bottom of the blades
should be at least 30 feet above any obstruction (trees buildings, etc.) within 500
feet. The entire rotor needs to be well above obstructions, so start your measurement
from the tip of the lowest blade.
Three basic tower types are used for almost all home-scale wind generator
installations. Tilt-up towers make maintenance easy, with no climbing. Fixed, guyed
towers are very common, climbable towers. Freestanding towers that resemble the
Eiffel Tower, with no guy wires, are costly, but attractive, and also climbable.
Tilt-up towers (See the video below) Tilt-up towers come in heights up to around 130
feet (40m) for small-scale machines. The most common tilt-ups are tubular steel, with
sections of pipe coupled together, and guy wires attached at each joint.
Tilt-up towers consist of the tower pole and a “gin pole” that is attached to it at 90
degrees. When the tower is down, the gin pole sticks straight up in the air. When the
tower is up, the gin pole rests horizontally near the ground. The gin pole is a big lever
that allows you to easily lift the tower, which pivots at its concrete base.
Fixed, guyed towers Another type of guyed tower, a fixed tower is lifted up once, and
does not tilt down. Guy wires hold it up, and any maintenance on the tower or turbine
is done by climbing the tower. These towers come in various configurations, the most
common being triangular lattice sections, 10 or 20 feet (3 or 6 m) long, that bolt
together. You’ve probably seen this type of tower used for commercial radio antennas
and the like.
Freestanding towers If your budget isn’t tight, a freestanding tower might be your
first choice. No guy wires, and it only needs a modest clear space for the tower base.
The drawback, of course, is cost. Freestanding towers rely on steel and concrete to
hold them up instead of guy wires—lots of steel and concrete. This means higher cost
for these materials, as well as for excavation, concrete forms, rebar, and labor.
Freestanding towers take two basic forms. Most common is the three-legged Eiffel
Tower style, with tubular legs connected by angle iron braces. The other option is a
monopole tower—a large, single tube, similar to what is used for utility-scale wind
Will it help the environment if I install a wind turbine at my home?
Wind turbines produce no pollution and by using wind power you will be offsetting
pollution that would have been generated by your utility company. Over its nominal 30
year life, a BWC EXCEL wind turbine will offset approximately 1.2 tons of air pollutants
and 200 tons of greenhouse gases.
Will the utility company allow me to hookup a wind generator?
Federal regulations (PURPA) require utilities to allow you to install a wind generator,
and pay you for any excess power you produce.
Will I have to change any of the wiring in my house?
No, a wind turbine is easily retrofitted to virtually any home without need of changing
any wiring or appliances. In some states a second utility meter will be added so the
utility can know how much electricity you have sold to them.
How are they as an investment?
That depends on your cost of electricity and average wind speed. The wind system will
usually recoup its investment through utility savings within 6-15 years and after that
the electricity it produces will be virtually free.
Compared to purchasing utility power, a wind system can be a good investment
because your money goes to increasing the value of your home rather than just
paying for a service. Many people buy wind systems for their retirement because they
are concerned about utility rate increases.
In addition to the new 30% energy tax credit, many states in the USA offer various
types of tax incentives and even rebates for your wind system. Follow the link to see
what incentive programs your state offers for a small wind systems.
A Ford van, out of camera range,
is all the power needed to raise
this 55' guyed tower. The
leverage to raise the tower is
provided by the gin pole and
pulleys. The longer the gin pole,
the easier it is to control the
speed at which the heavy tower
and turbine assembly can be
raised and lowered.
The pole pivots on a hinged
base plate. The guy wires are
attached before the tower is
raised and then tightened with
Guyed tilt up tower with guide pole
|Freestanding lattice tower
|Freestanding monopole tower