Electrical reference chart
Solar Resource Peak Sun Hours Chart
Use this worksheet after the calculator result to record the solar resource basis behind a PV production screen: NREL PVWatts result, NSRDB weather dataset note, user-entered peak sun hours, tilt, azimuth, source date, seasonal basis, shade note, and the next production-model handoff.
Quick reference table
A peak sun hours chart is a calculator-led planning worksheet: peak sun hours x system kWdc estimates daily kWh before losses. Record PVWatts or NSRDB source data, tilt, azimuth, source date, annual kWh, and seasonal assumptions before system sizing or ROI.
Solar resource worksheet
| Item | Record on worksheet | Why it matters |
|---|---|---|
| Location basis | Address, ZIP code, latitude/longitude, or station note | Solar resource varies by site and weather dataset |
| Resource source | NREL PVWatts, NSRDB, installer model, or user-entered value | The worksheet must show where peak sun hours came from |
| Array geometry | Tilt, azimuth, array type, and shade note | Geometry changes useful irradiance and seasonal output |
| Review date | Weather data year or dataset, source date, reviewer | Resource data and project assumptions can change over time |
Peak sun hours handoff
| Use case | Worksheet field | Boundary |
|---|---|---|
| System sizing | Peak sun hours, losses, performance ratio | Use as a planning screen before site-specific modeling |
| Row spacing | Tilt, latitude, seasonal sun angle note | Do not mix annual production tilt with winter shadow geometry without labeling it |
| ROI and emissions | Annual kWh source, source date, degradation note | Financial and carbon worksheets need the production basis visible |
| Proposal review | PVWatts or model file, weather dataset, shade note | Use the worksheet before final engineering and production modeling |
Solar resource chart to calculator handoff
| Search intent | Open the calculator when | Keep on this chart |
|---|---|---|
| Peak sun hours lookup | You need to turn a documented resource value into daily or annual kWh | Resource source, source date, and weather dataset |
| PVWatts production screen | You have DC size, losses, tilt, and azimuth ready for a system-sizing run | PVWatts assumptions and model limitations |
| Row-spacing review | Tilt or seasonal sun angle changes the array layout decision | Tilt, azimuth, seasonal basis, and shade note |
| ROI or emissions handoff | Annual kWh needs to feed finance, carbon, or owner-review worksheets | Selected production basis and source date |
How to use this chart
Record the resource source
Write whether the value came from NREL PVWatts, NSRDB, an installer model, a measured source, or a user-entered planning assumption.
Attach array geometry
Record tilt, azimuth, array type, shade note, loss basis, and whether the value is annual, seasonal, or monthly.
Route production review
Carry the source date and resource notes into system sizing, ROI, emissions, and installer review.
Formula basis
Planning daily kWh = system kWdc x peak sun hours x performance ratio. Annual kWh should be checked against NREL PVWatts or another source-backed production model before proposal use.
- Peak sun hours is the equivalent full-sun resource used for a planning estimate, not an assured production result.
- NREL PVWatts records site location, selected weather data, tilt, azimuth, DC size, losses, DC/AC ratio, and inverter assumptions.
- NSRDB identifies the solar radiation and meteorological dataset behind many U.S. solar-resource workflows.
- Tilt is the array angle from horizontal and should match roof, rack, or design assumptions.
- Azimuth records the array compass direction and helps explain production differences between south-, east-, and west-facing arrays.
- Source date records when the PVWatts, NSRDB, or other solar-resource value was retrieved or approved.
Worked examples
Residential PVWatts handoff
Record the address or ZIP, PVWatts run date, selected weather dataset, tilt, azimuth, losses, peak sun hours basis, first-year kWh, and whether shade modeling is still pending.
Ground-mount tilt comparison
Document candidate tilt, azimuth, seasonal resource basis, row-spacing note, peak sun hours, PVWatts annual kWh, and reviewer follow-up before moving to array sizing.
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Related charts
Solar Panel Output Chart
Use a solar panel output chart to document panel watts, panel count, peak sun hours, PVWatts-style losses, daily kWh, average monthly kWh, annual kWh, degradation, and offset notes.
Solar System Sizing Chart
Use a solar system sizing chart to document monthly load, target offset, peak sun hours, PVWatts-style losses, panel count, array kW, first-year production, degradation, and roof fit.
Solar Row Spacing Chart
Use a solar row spacing chart to document latitude, solar altitude, array tilt, row length, shadow length, row pitch, and GCR.
Frequently asked questions
These answers explain how to use the chart without turning a quick reference into a final design decision.