Solar PV Energy Yield Calculator
Daily and annual energy from array size, peak sun hours and performance ratio. With the formula, a worked example and typical values.
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Estimate only. Not engineering or safety advice. Check the result against the applicable standard and the equipment data, and have a competent engineer review it before it is relied on. Terms of use.
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About this calculator
This page calculates energy per day and energy per year from array size, peak sun hours per day and performance ratio. Change any value or its unit and the result updates. The steps below show the working for the default values, so you can check each line against your own method.
Limits of this calculator
Annual output falls about 0.5% per year with module ageing.
Cross-check: 6 reference cases, calculated from textbook formulas coded separately from the engine by the same author, agree with this calculator. This is not an independent review.
Verification status: Indicative
Indicative. Estimation only; further engineering checks are required. Basis: Yield estimate from a performance ratio.
What this calculator checks
- The arithmetic of the simplified model for the values you entered.
What remains unverified
- Whether the simplifying assumptions listed on this page hold for your case.
- Any standard, manufacturer or site data. Treat the result as an estimate and confirm it by a further engineering check.
Verification register entry
| Calculation author | Rahul Sharma (author) |
|---|---|
| Technical review | No independent technical review has been carried out |
| Individual professional approval | Not recorded |
| Formula reference | not recorded |
| Standard and edition | IEC 61724-1, 2021 Ed 2.0 |
| Standard review state | Public-scope screened; licensed clause review still pending |
| Scope-screening note | PV-system performance monitoring and performance-ratio terminology are relevant. The calculator is a simplified peak-sun-hours × performance-ratio estimate, not an IEC monitoring or yield-prediction implementation. |
| Cross-check test cases | 6 reference vectors (tests/reference_vectors.json) |
| Review date | not recorded |
| Next review date | not recorded |
| Status | Indicative |
Needed before this calculator can be marked Verified: reviewer name, qualification and review date; licensed clause-by-clause standard review; exact formula reference; formula source (textbook or standard); next review date.
Formula
Worked example
| Input | Value |
|---|---|
| Array size (peak) | 100 kW |
| Peak sun hours per day | 5.5 |
| Performance ratio | 0.78 |
- E(day) = 100 × 5.5 × 0.78 = 429 kWh
- E(year) = 429 × 365 = 156,585 kWh
Assumptions
- Average day over the year
- No degradation or shading beyond the PR
Annual output falls about 0.5% per year with module ageing.
Inputs and results
| Input | Unit | Allowed or shown | Note |
|---|---|---|---|
| Array size (peak) | kW | greater than 0 kW | |
| Peak sun hours per day | (number) | greater than 0, up to 12 | |
| Performance ratio | (number) | greater than 0, up to 1 | Typical 0.75 to 0.85 after all losses |
| Result | Unit | Allowed or shown | Note |
|---|---|---|---|
| Energy per day | kWh | Shown to 1 decimal place | |
| Energy per year | kWh | Shown to 0 decimal places |
How it is calculated
Each input is converted to the base unit of its quantity, the formula above is applied in the order shown in the worked example, and each result is shown in the unit you choose. Results are held at full precision and rounded only for display, except where a step selects a standard size, as the worked example shows. A value outside its allowed range is refused with a message instead of giving a result.
How the result changes with array size (peak)
| Array size (peak) (kW) | Energy per day (kWh) | Energy per year (kWh) |
|---|---|---|
| 10 | 42.9 | 15,659 |
| 25 | 107.3 | 39,146 |
| 50 | 214.5 | 78,293 |
| 100 | 429 | 156,585 |
| 200 | 858 | 313,170 |
| 400 | 1,716 | 626,340 |
| 1,000 | 4,290 | 1,565,850 |
Other inputs are the same as in the worked example above.
Standards and further reading
- IEC 62548 (photovoltaic array design requirements)
Module and battery limits come from the manufacturer data sheet; local grid codes set connection rules. These are named as background reading. Elecmetric does not embed clause text or rating tables, and the reviewer record for this calculator is separate from this list.
Frequently asked questions
What do I need to enter?
Enter array size (peak), peak sun hours per day and performance ratio. Change the unit of a value with its selector and the result stays the same.
What does this calculator assume?
Average day over the year. No degradation or shading beyond the PR.
Which calculators should I use next?
Common next steps are Solar PV String Length and Appliance Running Cost (Energy and Cost). The related links at the bottom of this page open them.
How accurate are the results?
Every figure comes from the same tested engine as the Elecmetric calculators and is meant for estimating. 6 reference cases, calculated from textbook formulas coded separately from the engine by the same author, agree with this calculator. This is not an independent review. Check design values against the standard and the equipment data you work to.
Formula guides and reference
Longer explanations with worked examples and tables, written for the same topic.
- Solar PV Formulas: Array Size and Strings: Solar PV formulas for array size from daily energy, yearly yield
- Solar Energy Yield and Degradation Formulas: Solar PV yield formulas: the yearly energy from array size, peak sun hours and performance ratio
- Solar Panel Temperature Derating Formulas: Solar panel temperature formulas: cell temperature from air temperature and irradiance with NOCT
More Renewable Energy calculatorsAll engineering calculatorsSolar PV Energy Yield in Elecmetric