What IST PV Solar Simulator Hands an EPC

The yield number is the easy part

An EPC rarely loses a project because the energy estimate was off by one percent. It loses time, and sometimes the client, in the two weeks after the simulation.

That is when someone rebuilds the same project in a spreadsheet for the financial model. Someone else draws the single-line diagram in CAD, and a third person types the BOQ and the quotation in Word. The bank then asks where the irradiation data came from, and the answer sits in a fourth file.

Every copy is a chance for the module count, the cable size or the tariff to drift. IST PV Solar Simulator was built around one idea: the project is entered once, and every document is produced from that single record.

36 outputs from one project record

One project in IST PV Solar Simulator produces 36 distinct outputs: 6 print-ready documents, 8 project data files and 22 research exports.

The six print-ready documents are the ones a client, a lender or a site engineer actually reads.

The eight data files carry the same project into Excel, a lender's model or an O&M system.

The Research tab adds 22 further exports in CSV, JSON, LaTeX and BibTeX. They cover sensitivity sweeps, uncertainty tables, and shading, inverter and battery studies.

What this changes for an EPC

The EPC enters the project once and every document reads from it. That removes the retyping step where most errors start.

• Numbers cannot drift. The proposal will not print until the simulation and the economics have been run. Its P50, P90, performance ratio and LCOE are the simulated values, not typed ones.
• The BOQ follows the design. Module and inverter counts in the 11-line BOQ come from the sub-arrays. Cable and clamp quantities are marked as estimates so nobody mistakes them for a final take-off.
• Company details are entered once. Company profile, customer details, cover letter and terms are saved as templates and reloaded for the next bid.
• The engineer and the salesperson share one file. The same record gives the client a proposal, the site team a wiring diagram and cable schedule, and the lender a bankability report.
• Costs can stay private. A switch hides item-wise cost in the proposal when the EPC wants to quote a lump sum.
• Component data comes in fast. Modules and inverters load from .PAN and .OND files, from a PDF datasheet, or by hand, on top of 451 modules and 344 inverters built in.
• It fits Indian projects. GST per line item, DISCOM and net-meter charges, and amounts in lakh are already in the cost tables.

How it differs from PVsyst, HelioScope and RatedPower

Each of the four tools was built for a different deliverable. IST PV Solar Simulator is the one built around the EPC's full document pack for a commercial, industrial or rooftop project.

Three points separate IST PV Solar Simulator from the rest.

• The bankability report is a document, not a setting. It adds contractor review, permitting status, covenant checks, conditions precedent and environmental and social compliance to the energy numbers.
• Site drawings come from the same record. The wiring diagram and the cable schedule are generated next to the yield, so the electrical design and the energy model describe the same plant.
• The proposal is part of the tool. The reviewer cited above notes that PVsyst users buy a separate proposal tool and a CAD seat. Here both jobs are inside one login.

The others keep real advantages. The same review says lenders and independent engineers still ask for a PVsyst report by name. RatedPower's document set for a utility-scale plant is far larger than ours.

Many EPCs will use both. IST PV Solar Simulator reads .PAN and .OND files, so a PVsyst cross-check runs on the same module and inverter data.

How the documents earn a bank's trust

A bank trusts a number it can trace. The bankability report is laid out around the questions a credit officer and the technical advisor ask, in the order they ask them.

The report is honest about its own inputs. If the yield rests on free satellite data, the document says so in plain words, which is what a careful lender wants to see.

It does not replace the lender's independent engineer. It hands that engineer a complete, ordered file on day one, which shortens the review instead of starting it.

What a project developer gets

A developer needs to know whether a project is worth pursuing before paying for detailed engineering. The same document set answers that at screening stage and again at financial close.

• Screening in one sitting. Batch simulation, automatic tilt optimisation and a tracker versus fixed-tilt comparison show which design is worth carrying forward.
• A lifetime view, not a first-year number. The year-by-year table carries degradation, energy and revenue through the project life. The lifetime Monte Carlo puts a range around it.
• Two financial models. A project-level model gives unlevered IRR, NPV and LCOE. An equity-level model adds debt, tax and depreciation for the investor's return.
• Sensitivity made visible. A tornado chart ranks which inputs move annual energy most, so negotiation time goes to the terms that matter.
• Grid and storage included. Transformer losses, export limits and power-factor reserve are in the loss tree. An AC-coupled battery study covers self-consumption, peak shaving and backup hours.
• One file for every party. The landowner, the offtaker, the EPC and the bank each receive a document drawn from the same project record.

The evidence, and how to check it yourself

Our claim is narrow and checkable: of the four tools compared here, only IST PV Solar Simulator produces this full document pack for a C&I project from a single record. We do not claim a more accurate yield than PVsyst.

Three things back the claim, and each can be verified without taking our word for it.

• The documents exist. Every item in the list above is a button in the software. Run one project and count them.
• The working is open. A 128-row table lists every default parameter and its source. The Run tab lists the formulas used. The hourly file exposes about 50 variables per step.
• The model can be tested against a real plant. The benchmarking module aligns simulated output with imported SCADA data. It reports mean bias, mean absolute error and RMSE by month, by irradiance band and by hour of day.

A three-step test on your own project settles the question better than any brochure.

1. Load the same .PAN file, .OND file and PVGIS weather year into IST PV Solar Simulator and into PVsyst. Compare the two loss trees line by line.
2. If the plant is already running, import one year of SCADA data and read the bias.
3. Time the pack. Measure how long it takes to go from a finished simulation to a proposal, a bankability report and a wiring diagram.

Sources: PVsyst release notes, Heaven Green Energy PVsyst review (its publisher sells a competing product), HelioScope product page,RatedPower. Document counts for IST PV Solar Simulator are taken from the software build dated 2 October 2026.