Powerlily calculates production from the physical system model, including the site geometry, module placement, equipment, weather data, losses, and modeled shading. This guide explains how to calculate the results, check whether they are credible, and use them in proposals and project documents.
Finish the physical model first
Production results are only as reliable as the scene that produces them. Before calculating, confirm the property location, roof or mounting-surface geometry, array layout, panel orientation, tilt, equipment, nearby trees, and obstructions.
Correct major geometry problems before adjusting loss assumptions. A clean-looking annual total does not compensate for an inaccurate roof, missing tree, or misplaced array.
Calculate production
Open the design workspace and use Calculate when the simulation banner indicates that production needs to be updated. Powerlily runs the current model and then makes the detailed system results available.
Recalculate after changing array geometry, module count, equipment, shading objects, site data, or simulation settings. Until you do, the displayed result may describe an earlier version of the scene.
Open the results view
Use Production, Balance of System, or the Results strip to open the results view. Review the total system as well as the individual arrays and panels that contribute to it.
Understand the annual simulation
The physical scene drives an hourly simulation across a full year. Powerlily evaluates panel-level irradiance and modeled obstruction effects, then uses the system configuration and production engine to calculate monthly and annual output.
The saved results can include array capacity, AC capacity, monthly production, annual production, and shading or loss values. These figures flow back to the quote and can be used in proposals, financial projections, reports, and option comparisons.
Inspect panel-level shading
Use the shading heatmap and time, day, or season shadow views to find modules that are consistently affected by nearby geometry. Look for patterns caused by trees, chimneys, dormers, parapets, neighbouring structures, or self-shading between rows.
Panel-level results are especially useful when an acceptable system total hides a small group of poorly performing modules. Consider removing or repositioning those modules, changing row spacing, or revising the array layout.
Review solar-access and obstruction metrics
Review the available solar-access and obstruction metrics for each array or surface. Compare similar roof planes and investigate unexpected differences. A dramatic result on an otherwise comparable plane often points to missing geometry, an incorrect object height, or an array assigned to the wrong surface.
Check the production assumptions
Confirm the assumptions that materially affect the result:
- Project location and weather source.
- Module and inverter specifications.
- Array type, tilt, and azimuth.
- DC and AC system capacity.
- System-loss assumptions.
- Modeled trees, structures, and rooftop obstructions.
- Row spacing and self-shading for tilted or ground-mounted arrays.
- Clipping and other equipment behaviour.
When changing an assumption, record why it differs from your normal company practice or the selected dataset.
Compare design options carefully
Calculate each quote option independently. Options with different equipment, system size, storage, orientation, or shading exposure should not be assumed to share the same production profile.
Compare annual output, monthly shape, capacity, shading impact, and customer value. Make sure the proposal explains the actual trade-off instead of showing several unexplained totals.
Save the results back to the quote
Save the design after reviewing the calculation. Powerlily carries the current array and production data back to the quote, where it can drive proposal content, utility-bill modelling, financial projections, and design documents.
After saving, confirm that the quote displays the intended system size and annual production. If the design changes later, recalculate and save again.
Generate reports
Under Documents, generate the shading or production reports required by your process. Reports can summarize the system, annual and monthly production, and simulation metrics derived from the saved design.
Store the report with the project and regenerate it after material design changes. Do not distribute an older report with a newer proposal or plan set.
Troubleshooting unexpected results
- Production is too high: check the location, system capacity, losses, inverter limits, missing shading objects, and unrealistic module placement.
- Production is too low: check surface orientation, pitch, object heights, duplicated obstructions, incorrect equipment data, and exaggerated losses.
- One array differs sharply: inspect its assigned surface, orientation, shading, and equipment.
- Results did not change: recalculate after the edit and confirm that the revised design was saved.
- The proposal shows an old value: verify that you saved the correct quote option and regenerated any cached document.
Final review checklist
- The scene matches the best available site information.
- All intended arrays and panels are included.
- Trees and obstructions use realistic positions and heights.
- Equipment and capacity values are correct.
- Production has been recalculated after the latest changes.
- Panel-level shading and monthly results have been reviewed.
- The saved quote shows the current annual production.
- Proposal and report values belong to the same design revision.
