Example Data Table
| Hour |
Irradiance (W/m²) |
Cell Temp (°C) |
Temp Factor |
AC Output (kWh) |
| 07:00 - 08:00 |
245.00 |
37.66 |
0.9557 |
1.7210 |
| 09:00 - 10:00 |
671.75 |
50.99 |
0.9090 |
4.5103 |
| 12:00 - 13:00 |
941.87 |
59.43 |
0.8790 |
5.9156 |
| 14:00 - 15:00 |
776.06 |
54.25 |
0.8971 |
5.0988 |
| 17:00 - 18:00 |
122.87 |
33.84 |
0.9686 |
0.8825 |
Formula Used
1. DC system size: DC Size (kW) = Panel Count × Panel Wattage ÷ 1000.
2. Hourly irradiance profile: Irradiance = Peak Irradiance × sin(π × daylight position). This creates a smooth daylight curve between sunrise and sunset.
3. Cell temperature: Cell Temp = Ambient Temp + ((NOCT - 20) ÷ 800) × Irradiance.
4. Temperature factor: Temp Factor = 1 + (Temperature Coefficient ÷ 100) × (Cell Temp - 25).
5. Base derate: The calculator multiplies inverter efficiency, availability, cloud factor, tilt factor, and remaining energy after system, soiling, shading, and degradation losses. Bifacial gain raises the result.
6. Hourly AC output: Hourly Output (kWh) = DC Size × (Irradiance ÷ 1000) × Base Derate × Temp Factor.
This model is practical for fast estimates. It is not a replacement for site measured plane of array data or full simulation tools.
How to Use This Calculator
- Enter a project name if you want a labeled report.
- Add the number of modules and wattage per module.
- Enter loss values for inverter, system, soiling, shading, and degradation.
- Set the availability, tilt factor, and cloud factor.
- Provide ambient temperature, NOCT, and module temperature coefficient.
- Enter sunrise, sunset, and the expected peak irradiance near noon.
- Add bifacial gain only when the module and site support it.
- Press the calculate button to generate hourly energy output and summary metrics.
- Use the export buttons to save the result table as CSV or PDF.
Hourly Solar Production Insights
Why Hourly Solar Output Matters
Hourly solar production matters because energy is not flat all day. Output rises after sunrise. It peaks near midday. Then it declines before sunset. A detailed calculator helps homeowners, installers, and analysts see this pattern clearly. It turns a simple daily estimate into useful hourly planning data for homes and businesses.
Inputs That Shape Photovoltaic Performance
This calculator uses panel count, panel wattage, irradiance, inverter efficiency, shading, soiling, system loss, and temperature effects. Those variables shape real photovoltaic performance. They also explain why the same array can produce different energy across seasons, roofs, and weather conditions. Better hourly estimates support system sizing, appliance scheduling, battery charging, and export planning.
Temperature, Irradiance, and Real Output
Solar irradiance drives the largest hourly change. More sunlight means more available DC power. Heat can reduce module performance. That is why the calculator applies a cell temperature model using ambient temperature and NOCT. It then adds a temperature coefficient adjustment. This gives a more realistic estimate than a flat performance ratio alone.
Losses and System Derates
Losses also matter. Inverter conversion is never perfect. Dust lowers panel output. Partial shading can suppress several modules. Wiring and mismatch losses further reduce usable energy. The calculator combines these derates into one practical hourly production estimate. It also includes tilt or orientation influence, cloud factor, availability, degradation, and optional bifacial gain.
Why the Summary Table Helps
The result table shows every hour of the day. You can compare irradiance, cell temperature, temperature factor, and AC energy output. The summary section highlights system size, total daily energy, peak production hour, average daylight output, and estimated capacity factor. These numbers help users judge whether the system matches household demand or project goals.
Planning Better Solar Decisions
Hourly solar data is also useful for battery strategy. You can see charging windows. You can spot weak afternoon production. You can estimate when self-consumption is strongest. Installers can compare different derate assumptions fast. Students can learn how weather and heat change photovoltaic output hour by hour.
Use the calculator for rooftop studies, preliminary proposals, classroom work, and operational reviews. It is ideal for quick checks before detailed simulation software. Enter strong assumptions for clear results. Then refine them with site data, measured irradiance, and seasonal profiles. Accurate hourly solar production estimates lead to better energy decisions.
Frequently Asked Questions
1. What does this hourly solar production calculator estimate?
It estimates hourly AC energy output from a solar array. It uses panel size, irradiance, losses, temperature, and daylight duration. The result is a practical daily production profile.
2. Why does the calculator ask for peak irradiance?
Peak irradiance sets the midday sunlight intensity. The calculator uses it to shape the hourly irradiance curve between sunrise and sunset. Higher values usually increase hourly output.
3. Why is temperature coefficient important?
Solar modules usually produce less power when cell temperature rises. The temperature coefficient adjusts output around standard test conditions. This improves realism during hot daytime hours.
4. Is this suitable for battery planning?
Yes. Hourly output helps identify charging windows and surplus periods. It is useful for first pass battery sizing, load shifting, and self consumption studies.
5. Does the calculator replace solar simulation software?
No. It is a fast planning tool. Detailed tools use site weather files, array geometry, and electrical models. This calculator is best for quick hourly estimates.
6. What is the base derate percentage?
Base derate is the combined effect of inverter efficiency and energy reducing factors. It includes system losses, soiling, shading, tilt, cloud impact, availability, degradation, and bifacial gain.
7. Why are some early or late hours zero?
Hours outside the sunrise to sunset window have no modeled irradiance. Very low light periods may also produce tiny values. That is normal for hourly solar production curves.
8. Can I export the result table?
Yes. After calculation, use the CSV button for spreadsheet analysis or the PDF button for sharing. Both export the summary and hourly production details.