How to use this calculator
- Enter project values using the units shown beside each field.
- Select Calculate to update the main estimate and supporting results.
- Review the interpretation and test realistic high and low assumptions.
#1015 · Energy & Environment Tool
Community Solar System Sizing Calculator
Estimate the community solar array capacity needed to meet a target annual electricity production using local solar resource and expected system losses.
Calculator
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Formula
Required capacity (kW) = target annual generation ÷ (peak sun hours/day × 365 × performance ratio)
What the result means
The result is the approximate rated solar capacity required to produce the target energy in a typical year.
This is an energy-based preliminary size. Land, grid interconnection, DC/AC ratio, clipping, curtailment, setbacks, and module layout require separate engineering.
Example calculation
To generate 1,500,000 kWh annually with 4.5 peak sun hours and an 82% performance ratio requires about 1,113.71 kW.
Tips for better results
Add an explicit planning margin only after establishing realistic weather variability, degradation, and curtailment assumptions to avoid double-counting losses.
Keep units and AC/DC or gross/net definitions consistent across every input.
Frequently asked questions
What does this community solar system sizing estimate show?
The result is the approximate rated solar capacity required to produce the target energy in a typical year.
Can I use this result for a final investment or engineering decision?
No. Use it as a screening estimate and confirm project-specific assumptions with qualified engineering, financial, utility, and tax professionals.
Why might actual results differ?
Weather, equipment performance, outages, degradation, curtailment, tariffs, operating strategy, and data-basis differences can all change actual outcomes.
Should I use AC or DC solar capacity?
Use the capacity basis specified by the input label and keep every production or performance value on the same basis.
How often should I update the estimate?
Update it whenever design ratings, resource studies, operating data, tariffs, incentives, battery condition, or project costs change.
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Quick reference
| Item | Guidance |
|---|---|
| Best use | Early-stage screening and scenario comparison |
| Update when | Design, resource, cost, tariff, or operating assumptions change |
| Decision quality | Confirm with project-specific engineering and financial analysis |