Answer
Solar shadow analysis software estimates how obstructions and array geometry affect solar access and, where supported, energy production. Evaluate the source and age of the site model, obstruction dimensions, horizon, module layout, electrical configuration, and calculation method. A shadow animation, shaded-area percentage, or irradiance loss is not automatically an annual AC-energy loss. Corroborate material site inputs and preserve review limitations.
A realistic shadow animation can still use an obsolete tree height or the wrong module arrangement. The buying question is whether the software exposes those inputs and produces a result fit for the intended decision.
This guide covers evaluation and report acceptance. SurgePV’s shadow analysis product page describes the commercial workflow; this article does not certify its accuracy, a competitor’s accuracy, or any particular site’s production.
Define the output you need
| Output | What it describes | What to ask |
|---|---|---|
| Shadow view | Geometry at a specified date and sun position | Are location, time convention and object dimensions recorded? |
| Solar-access or irradiance result | Available resource or an irradiance deficit under a defined method | What is the baseline, period and radiation treatment? |
| Electrical mismatch result | Interaction of differently illuminated modules or strings | Which module arrangement and electrical model were used? |
| Annual production result | Energy at a specified output boundary over a modelled period | Which weather, equipment and loss assumptions are included? |
Do not compare percentages until their denominators, periods and meanings match. A single moment’s shaded-area fraction is not a production forecast.
Verify the site representation before interpreting losses
Keep an input register for coordinates, roof planes, tilt and orientation, module placement, obstruction location and height, horizon, and relevant terrain. For each, retain its source date, measurement or assumption, owner, and uncertainty.
Check imagery age, hidden objects, tree condition, adjacent construction and height evidence. Corroborate material conflicts using the project’s survey and review process. A site photograph is supporting evidence, not a complete height or roof-dimension measurement by itself.
Preserve the original article’s distinction between early screening and design review. Screening identifies unresolved risks; it must not be labelled field verification. Ask whether the user can edit an obstruction, show its assumed height, and retain the scene version that produced a report.
Separate geometric, irradiance and electrical shading
PVsyst’s current shading documentation distinguishes distant horizon shading from nearby objects requiring a detailed scene. It also separates irradiance deficits from electrical mismatch and describes simplified string-based versus detailed module-layout methods.
Its calculation documentation treats radiation components separately and describes electrical mismatch calculations using module placement and electrical relationships. Optimizers may recover part of mismatch losses under applicable conditions; this does not recover the sunlight an obstruction blocks.
These are vendor-documented model distinctions, not proof that another program implements the same methods. Ask the proposed vendor what its current version actually calculates, what it approximates, and what must be entered by the designer. Do not turn a model’s assumptions into a universal claim about every shaded array.
Make the layout and electrical configuration agree
A scene and a string schedule should refer to the same revision. Verify actual module orientation and placement, string membership, inverter/MPPT allocation, and any supported power electronics before relying on an electrical-loss result.
If the software only evaluates irradiance shading, describe that limitation. Do not imply that its visual output resolves bypass-diode behaviour, mismatch, clipping, or inverter operating limits without the corresponding documented model.
A change in module position or obstruction geometry should trigger the relevant rerun. A change in equipment or strings should reopen electrical and production review even when the roof picture looks unchanged.
Test a representative scene and its revisions
Use a buyer-defined test project with independently corroborated dimensions. Include the obstructions and roof complexity relevant to your work; a generic clear roof cannot test those requirements.
- Reconcile the scene with the recorded site evidence and coordinate conventions.
- Inspect shadows at identified dates and times, keeping the time basis explicit.
- Change one declared obstruction or layout input and trace the resulting report revision.
- Check the radiation and electrical methods and the equipment/configuration they use.
- Inspect annual outputs and loss boundaries; do not subtract an already-included loss again.
- Export the assumptions and results for a reviewer who did not build the model.
This review does not specify a universal acceptable error percentage. Define acceptance criteria for the decision, sources, method and required professional review. Explain residual uncertainty instead of hiding it in a polished image.
Release a report another person can inspect
The handoff should identify the site evidence, scene and layout revision, weather basis, equipment and electrical arrangement, method/version, result definitions, reviewer, and unresolved conditions. Preserve changes and reasons, not just the final screenshot.
Use the shade-report reading guide for interpreting report fields and the shading design review workflow for deciding when to reopen review. These supporting guides serve different tasks from product selection.
For a SurgePV demo, bring a representative scene and request a demonstration of the presently supported inputs, loss outputs, editing, export and revision steps. Record any survey, specialist simulation, electrical review or unsupported requirement before purchase. Present customer projections through the approved solar proposal workflow, preserving their assumptions and limitations.
Frequently Asked Questions
What should buyers check in solar shadow analysis software?
Check site and obstruction sources, geometry editing, horizon treatment, array and electrical layout, irradiance and electrical loss methods, weather basis, output definitions, revision traceability, and report export. Test the relevant project type with corroborated site evidence.
Is shaded area the same as annual solar-energy loss?
No. Shaded area describes geometry at a stated sun position. Annual energy loss also depends on time, irradiance, the electrical configuration, model assumptions, and output boundary. Identify the specific metric before comparing percentages.
Can satellite imagery replace site verification?
Remote imagery can support screening, but its age, resolution, visibility, and height information may leave material inputs unresolved. Use the project-required survey and review process to corroborate geometry and obstructions before relying on consequential projections.
Do optimizers eliminate shading losses?
No. Depending on the equipment, configuration, and shading pattern, power electronics may recover some electrical mismatch loss. They do not restore sunlight blocked by an obstruction. Evaluate the exact supported model and conditions rather than assuming a universal recovery percentage.
Sources
Primary research and reference material used for this desk-research article.
Where this fits
This article is part of SurgePV's Solar Design hub, which works through the topic from first principles to the decisions a project team actually has to make.
