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Micro Wind Annual Output Calculator

This calculator estimates how much usable electricity a micro wind turbine may produce in a year from its rated capacity, expected capacity factor, and additional system losses. Capacity factor summarizes the effect of changing wind speeds and turbine availability; it is not the percentage of time the rotor turns. The loss input then accounts for wiring, inverter, battery, icing, curtailment, or other deductions not already embedded in the factor. Small-turbine owners, rural property planners, and energy advisers can use the estimate to compare a proposed machine with annual electricity demand or to create a first-pass savings scenario. Because wind energy changes with the cube of wind speed before the turbine power curve and controls are considered, a site-specific wind assessment is far more reliable than a regional average. The output is therefore a planning estimate. Keep the capacity-factor and loss assumptions distinct to avoid counting the same downtime or inefficiency twice.

Calculation inputs

Result
—
Calculated result
Gross output—
Energy lost—
Average per month—

1. Enter nameplate capacity

Use the turbine's rated electrical output in kilowatts.

2. Choose a site-based capacity factor

Prefer an estimate derived from a measured wind distribution and the turbine power curve.

3. Add separate system losses

Include only losses not already reflected in the capacity factor.

4. Inspect annual production

The main result is net kWh for a 365-day year.

5. Compare with demand

Use the monthly average only as an annualized benchmark; actual monthly production will vary.

Net annual output = Rated capacity × 8,760 hours × (Capacity factor ÷ 100) × [1 − (Losses ÷ 100)]

Rated capacity is in kW, so multiplying by hours produces kWh. This method treats capacity factor as a full-year average and applies losses afterward.

What the result means

The result is the net electrical energy expected over a representative year under the entered operating assumptions.

Results are planning estimates based on the values entered. Confirm equipment limits, site conditions, and project assumptions before making a purchase or investment decision.

Given

A 5 kW turbine, 22% capacity factor, and 8% additional losses.

Calculation

Gross output = 5 × 8,760 × 0.22 = 9,636 kWh. Net output = 9,636 × 0.92 = 8,865.12 kWh.

Result

Estimated annual usable output is 8,865 kWh, or an annualized average of about 739 kWh per month.

Does a 22% capacity factor mean the turbine runs 22% of the year?

No. It means annual energy equals 22% of what continuous full-rated operation would produce. The turbine may operate at many power levels for much more than 22% of the time.

Where can I get a capacity-factor estimate?

Use site wind measurements, turbine power-curve modeling, and availability assumptions when possible. Nearby airport wind data can be misleading because height and terrain differ.

Should inverter loss be included?

Yes, if the production basis is turbine-side energy and inverter loss is not already included in the capacity factor. Do not deduct it twice.

Why is the monthly result not a forecast for each month?

It is annual net output divided by 12. Seasonal wind patterns can make individual months substantially higher or lower.

Can this replace a wind resource assessment?

No. It is a scenario calculator; final design should use hub-height measurements, terrain effects, setbacks, and the selected turbine's certified performance data.