Solar Output Calculator Widget
Embed a solar energy-yield estimator for a system someone already has or has been quoted. Readers enter the array size in kWp, their peak sun hours and a performance ratio, and see the expected daily, monthly and yearly generation, the specific yield and how much of their own use it covers.
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Under the widget on your page: Powered by A2Z Tools
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<iframe src="https://a2z.tools/embed/w/solar-output-calculator" title="Solar Output Calculator by A2Z Tools" width="100%" height="620" style="border:0;width:100%" loading="lazy" allow="clipboard-write"></iframe>
A plain iframe. Works everywhere, including site builders that strip scripts. Adjust height if your content needs more room.
<div data-a2z-widget="solar-output-calculator" data-height="620"></div> <script async src="https://a2z.tools/embed.js"></script>
Adds a small script (what it does) that sizes the widget to fit its content, loads it lazily and keeps it isolated from your page's CSS.
Works with
How it works
Peak sun hours are the day's solar energy on the panel plane expressed as hours of full 1 kW/m² sunshine, so a 1 kWp array would make 1 kWh per peak sun hour if nothing were lost. Real systems lose energy to heat, inverter conversion, wiring, soiling, shading and mismatch; the performance ratio wraps all of these into one figure. NREL defines it, following IEC 61724, as the electricity produced divided by what the array would make if it always converted sunlight at its nameplate efficiency, and notes values for new systems usually fall between 0.6 and 0.9. Daily output is therefore kWp x peak sun hours x PR: 5 kWp x 4.5 h x 0.80 = 18 kWh, or 6,570 kWh a year and 1,314 kWh per kWp (the specific yield used to compare sites and quotes). Monthly output is the annual figure over 12. Peak sun hours above 9 are refused because no location averages that over a year.
Calculation method
- Daily kWh = kWp x peak sun hours x performance ratio
- Annual kWh = daily x 365; monthly average = annual / 12
- Specific yield = annual kWh / kWp
- Share of use = annual kWh / annual consumption x 100
Worked examples
Rooftop 5 kWp
Inputs: 5 kWp; 4.5 peak sun hours; PR 80%
Result: 6,570 kWh a year; 547.5 a month; 18 kWh a day; 1,314 kWh/kWp
5 x 4.5 x 0.80 = 18; x 365 = 6,570.
Sunny-site 10 kWp against use
Inputs: 10 kWp; 5.5 h; PR 75%; annual use 10,000 kWh
Result: 15,056 kWh a year; 151% of use
10 x 5.5 x 0.75 = 41.25 kWh a day x 365 = 15,056.
An estimate for planning, not a performance guarantee.
Limitations
- A yearly average only; there is no month-by-month or hourly profile.
- Shade, tilt and orientation must already be reflected in the peak sun hours and performance ratio you enter.
- DC nameplate kWp is assumed; inverter clipping on oversized arrays is not modelled.
Where publishers use it
- Installers explaining what a proposed array will generate
- Owners checking whether their system is under-performing
- Off-grid cabin and boat guides estimating daily energy
- Comparison articles on PV in sunny and cloudy climates
- School and science-fair projects on renewable energy
Questions
Where do I find my peak sun hours?
Use a free modelling tool: NREL's PVWatts for the US and many other countries, or the EU's PVGIS for Europe, Africa and Asia. Take the yearly average of daily plane-of-array irradiation in kWh/m²; that number is the peak sun hours. Values are lowest at high latitudes and highest in sunny dry regions, so always use the figure for your site.
What performance ratio should I use?
NREL notes PR for new systems typically ranges from 0.6 to 0.9. Use about 0.75-0.85 for a well-designed, unshaded system, lower for hot climates, dirty panels or partial shade.
What is specific yield?
Annual output per kWp of panels. 1,314 kWh/kWp means each kilowatt of panels makes 1,314 kWh a year - a quick way to compare locations and quotes regardless of system size.
How is this different from the solar panel calculator?
The Solar Panel Calculator starts from your energy need and sizes the number of panels. This widget starts from an array you have or were quoted and estimates what it will produce.
Why is my monthly bill saving different from the average?
Output follows the seasons: away from the tropics, summer months produce far more than winter months. The monthly figure here is the yearly average divided by 12.
Do bifacial panels or trackers change the figure?
Yes. A single-axis tracker follows the sun and raises yearly output noticeably at sunny sites, and bifacial modules collect reflected light on their rear face over bright ground. Model those in PVWatts or PVGIS and carry their peak-sun-hour figure over here.
What does inverter clipping mean?
When the DC array is larger than the inverter's AC rating, the inverter caps output on the brightest hours. A DC/AC ratio around 1.2-1.3 clips little energy over a year, but this widget assumes no clipping at all.
Sources
- Weather-Corrected Performance Ratio (NREL/TP-5200-57991) - National Renewable Energy Laboratory (OSTI) . PR is defined in IEC 61724 as electricity generated over what would be generated at the DC nameplate rating; values for new systems typically range from 0.6 to 0.9.
- PVGIS - Photovoltaic Geographical Information System - European Commission Joint Research Centre . Free irradiation and PV-output data for Europe, Africa, Asia and the Americas.
Cite or recommend this tool
If you reference this tool in an article, course or documentation, these formats are ready to copy. They are optional - nothing is added to your site unless you paste it.
A2Z Tools Solar Output Calculator https://a2z.tools/embed/solar-output-calculator
<a href="https://a2z.tools/embed/solar-output-calculator">A2Z Tools Solar Output Calculator</a>
[A2Z Tools Solar Output Calculator](https://a2z.tools/embed/solar-output-calculator)
Solar Output Calculator by A2Z Tools - https://a2z.tools/embed/solar-output-calculator
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