Get Monthly Output Power (kWh/Month) For a Wind Turbine Based on Rotor Diameter (m):
Wind Turbine Power Output Calculator
Turbine Annual Energy Output
Scientific Equation:
KWH = 0.01328 x Rotor diameter (in feet)2 squared x average wind speed (mph)3 cubed
Eg; 5 KW Wind Turbine w/ 6.4 M rotor (19.2 feet)
Average wind speed of 6 m/s = 13.5 mph
Calculations:
Rotor Length Squared: 19.2 x 19.2 = 368.64
Average Wind Speed Cubed: 13.5 x 13.5 x 13.5 = 2460.375
Final Calculation:
0.01328 x 368.64 (rotor length in feet/squared) = 4.8955392
4.8955392 x 2460.375 ( wind speed in mph/cubed) = 12,045 KWH Annually
*Tip to calculate m/s to mph for wind speed: 1 m/s = 3.6 KM/H = 2.25 mph
What is the Photovoltaic potential in your area?
Natural Resources Canada

Photovoltaic potential (kWh/kW) Southfacing, tilt=latitude Annual

US Photovoltaic Potential:
Obtain performance estimates for gridconnected PV systems.
The PV Watt Photovoltaic Solar System Performance Calculator
Sizing A PV Array:
1. Determine what your KWh electric consumption is. Then match PV production to your electric consumption.
For example, if you consume 600 kilowatthours per month (KWh/month) and want to produce 100% of your
electricity with a PV system with no battery backup. Do this equation to calculate; 600 KWh/month x 12
months equals 7,200 KWh/year or approximately 20 KWh/day.
Most of the U.S. has 3.5 to 5 Sun Hours of solar input. This means that a 1 kilowatt AC PV system in a 4.5 Sun Hour region will produce 4.5 kilowatthours per day. 20 kWh/day divided by 4.5 sun hours equals 4.4 KW AC.
Go to "PVWATTS" at: http://rredc.nrel.gov/solar/calculators/PVWATTS/version1/
and enter your location, 4.4 KW, your roof tilt and orientation. See your monthly and annual estimated PV production for a 4.4 KW system or any other size system.
2. Match your PV array size to your roof space. You need full sun on your solar array all day (from at least 9am to 4pm). Trees, chimneys, vents and other buildings can block the sun or make array installation difficult. Square footage examples; 225 sq. ft. array (Qty of 32  70 Watt modules) / 140 sq. ft. array (Qty of 20  75 Watt modules).
3. Match your PV system cost to your budget. PV modules are about half of the total system cost. The other equipment you may need depending on your system configuration are mounting hardware, combiner boxes, disconnect switches, power center, charge controller, inverter, battery bank and wiring.
*Find out what State / Provincial or Federal Government incentives are available in your area.
Question: If I need 5KW for my house, do I choose a 5KW wind turbine?
Answer: You'll need to check the mean wind speed of your area. The tower height, terrain and location of the wind turbine will also dramatically affect the yield of the wind turbine.
If the wind speed for your area is more than 3m/s or 10.8km/h or 6.75mph for more than 3000 hours annually...
Congratulations!... You can enjoy the savings to use our wind turbines.
If not and you have enough sunshine in your area, then our Solar Panels may be a more suitable alternative for you.
The actual yield of the wind turbine depends on the wind speed in your area. If you have a mean wind speed bigger than 10m/s, you'll get the full benefit from the wind turbine. If you have a mean wind speed of 7m/s, you'll get roughly a 75% benefit from the wind turbine. Eg; 5000 Watt turbine: 75% benefit = 3750 Watts generated from the turbine.
*You can also choose a bigger wind turbine according to your budget. If you have a mean wind speed of less than 2m/s, a wind turbine may not be your best choice. You may consider solar power as a more suitable option.
You can also combine solar power with your wind turbine to fully meet the needs of your electricity consumption.
Question: How do you convert m/s to KM/H or MPH?
Answer: 1m/s = 3.6 KM/H = 2.25 MPH
Question: What if I can use both wind turbines and solar power in my area?
Answer: Because solar panels are more expensive than wind turbines, you should try to use as much wind power as
possible.
For a wind speed less than 4m/s (14.5km/h or 9mph)
>>> Use 90% solar and 10% wind.
For a wind speed more than 4m/s (14.5km/h or 9mph) but less than 5.36m/s (19.3km/h or 12mph)
>>> Use 50% solar and 50% wind.
For a wind speed more than 5.36m/s (19.3km/h or 12mph)
>>> Use 30% solar and 70% wind.
How many batteries do I need for my wind turbine?
The batteries you need depends on the hours that need to be used per day, let's assume that...
The unit battery capacity will be: 5000W x 6H x 1.67 / 240V = 208.75 AH or bigger. ( 1.67 is the factor we use for the calculation)
If you use 300 AH 12V batteries, you'll need 240V/12V = 20 units
How to Approximate the Wind Pressure:
Pressure = ?x (density of air) x (wind speed)^{2} x (shape factor)

The density of air is about 1.25 kg/m^{3}.

The shape factor (drag coefficient) depends on the shape of the body. It has order of magnitude 1 and is dimension less.

The wind speed must be expressed in m/s. In that case the pressure has units kg/m/s^{2}, i.e. N/m^{2}.
See this table:
Bft

Wind speed (m/s)

Wind pressure (N/m^{2})


Lower limit

Upper limit

Upper limit

0

0.0

0.2

0.03

1

0.3

1.5

1.4

2

1.6

3.3

6.8

3

3.4

5.4

18

4

5.5

7.9

39

5

8.0

10.7

72

6

10.8

13.8

119

7

13.9

17.1

183

8

17.2

20.7

268

9

20.8

24.4

372

10

24.5

28.4

504

11

28.5

32.5

660

12

32.6


> 660

How To Convert Gigawatts  Megawatts  Kilowatts  Watts:
Gigawatts, Megawatts, Kilowatts & Watts:
Electricity is measured in units of power called watts. The watt was named to honor James Watt, the inventor of the steam engine. One watt is a very small amount of power. It describes the rate at which electricity is being used at a specific moment. A kilowatt (kW) represents 1,000 watts. The amount of electricity a customer uses over a period of time is measured in kilowatthours (kWh). Kilowatthours are what you see on your electricity bill at home.
For example, if you use a 60watt bulb, 4 hours a day for 30 days, you have used 7.2 kW of electrical energy.
Sample Calculation: (60 watts) X (4 hours/day) X (30days) = 7200 watthours
7200 watthours/(1000 watts/kW) = 7.2 kW
Megawatts and Gigawatts  metric terms used to measure the output of a power plant or the amount of electricity required by an entire city.
1 megawatt (MW) = 1,000 kilowatts (kW) = 1,000,000 watts (1 million)
1 gigawatt (GW) = 1,000 megawatts (MW) = 1,000,000,000 watts (1 billion)
