Why EPCs search for a PVsyst alternative
PVsyst set the expectation for hourly photovoltaic simulation and lender-facing yield reports. Indian teams still deliver PVsyst PDFs on some utility mandates — but weekly bids need IS 875 wind zones, DISCOM context, and multi-source weather in the same run.
REEOS keeps the engineering posture (loss physics, PR, degradation, citations) while resolving Indian rules at coordinates and printing every cut in kWh.
Where REEOS fits your stack
Use REEOS as the primary simulation for rooftops and commercial roofs where transparency and speed matter. Pair with legacy desktop tools only when a term sheet names them explicitly.
See the dedicated PVsyst alternative page for a public feature matrix and FAQ.