Nimesh Katariya A PVsyst project file (.PRJ) is the file PVsyst uses to store a project's site, weather file and simulation variants. Each variant, saved as a linked .VCx file, holds the system layout, module .PAN and inverter .OND references, shading scene and loss assumptions. Lenders' independent engineers request these files to audit bankable yield reports.
What the.PRJ File Actually Contains
A single PVsyst project file bundles together everything needed to reproduce a yield simulation: the site’s geographic coordinates and weather data source, the module (.PAN) and inverter (.OND) files selected for the design, array orientation and tracker or fixed-tilt configuration, any 3D shading scene built for near-field or far-field obstructions, and the full set of loss assumptions, soiling, mismatch, DC/AC ohmic, availability, and degradation.
The simulation results themselves, including the loss diagram and monthly/annual yield tables, are stored alongside those inputs.
This is what separates a.PRJ file from a formatted PDF export: the PDF is a snapshot of the output, while the.PRJ file is the live, editable project that produced it.
Why It Matters for Bankable Documentation
Lenders and independent engineers reviewing an EYA rarely stop at the summary report. Because the.PRJ file preserves every input assumption in an editable form, an IE can open it directly in PVsyst, swap in an updated weather dataset or a revised soiling assumption, and see how the yield projection moves, a level of scrutiny a static document cannot support.
For that reason, submitting the.PRJ file alongside the PDF report is standard practice on any commercial or utility-scale project going through IE review or lender due diligence.
Related Reading
The.PRJ file only matters in the context of the simulation workflow that produces it, and our guide to bankable PVsyst reports walks through what reviewers expect to see in both the report and the underlying project file. For teams building the yield modeling skills that go into a well-structured.PRJ file, advanced PVsyst analysis for accurate yield predictions covers the assumptions that most affect downstream accuracy.
Since PVsyst is one of several tools engineering teams weigh when choosing a simulation platform, our roundup of solar design software options is a useful reference for where PVsyst project files fit relative to alternatives like Helioscope.
Example outputs built from .PRJ files are in the PVsyst resource center.
Disclosure: SurgePV is a Heaven Designs group company.
Frequently Asked Questions
3 commonly searched questions about PVsyst Project File (.PRJ).
Why do lenders ask for the PVsyst .PRJ file and not just the PDF report?
What is the difference between a .PRJ file and a PVsyst PDF report?
Can a PVsyst .PRJ file be opened without a PVsyst licence?
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