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Microgrid Capacity Factor Estimator

This calculator estimates the aggregate capacity factor of a microgrid’s generation portfolio. It compares total annual electrical generation with the energy that all entered generation capacity could have produced at full output for the entire year. The metric is useful for high-level portfolio benchmarking and year-over-year tracking. Because different technologies have different availability and resource patterns, the blended result should be interpreted alongside source-level capacity factors rather than as a performance rating for every asset.

Portfolio generation data

MWh
MW
hr
Result
—
Aggregate microgrid capacity factor
Maximum possible generation—
Average generated power—
Gap to full-output equivalent—

1. Enter total generation
Use electricity generated by the microgrid resources during the selected period.

2. Enter installed capacity
Add the rated capacities of all generation assets included in the energy total.

3. Set period hours
Use 8,760 for a standard full year or enter the exact hours for another reporting period.

4. Confirm matching scope
Exclude storage power capacity unless its discharged energy and charging treatment are intentionally included in the metric.

5. Review the blended factor
Compare it with source-specific factors and changes in the generation mix.

Maximum possible generation = Total installed capacity × Period hours
Aggregate capacity factor (%) = Actual generation ÷ Maximum possible generation × 100

The formula assumes the same total installed capacity was available as the denominator for the whole period. Capacity changes should be handled with capacity-hour weighting.

What the result means

The result shows the portfolio’s actual generation as a percentage of continuous full-rated generation over the selected period.

A blended capacity factor can fall when low-capacity-factor renewable capacity is added even if renewable energy production increases.

Given: Annual microgrid generation of 4,850 MWh, total installed generation capacity of 1.6 MW, and 8,760 hours.

Calculation:
Maximum generation = 1.6 × 8,760 = 14,016 MWh
Capacity factor = 4,850 ÷ 14,016 × 100 = 34.60%

Result: The aggregate capacity factor is approximately 34.60%.

Should battery inverter capacity be included?

Usually not when the metric is intended to describe primary generation utilization. Storage shifts energy and can double-count generation if discharge is treated as new production.

Can the blended capacity factor be compared with a utility plant?

Only cautiously. A microgrid may combine solar, wind, and standby generation with very different operating purposes.

What if capacity changed during the year?

Use capacity-hours for each interval rather than multiplying the year-end capacity by all annual hours.

Why might the result decrease after adding solar?

Solar can increase annual energy while also increasing the denominator substantially. The portfolio mix therefore affects the blended percentage.

Is this the same as renewable penetration?

No. Renewable penetration compares renewable energy or power with total load or generation; capacity factor compares energy produced with maximum possible output from installed capacity.