How to Evaluate a Solar Proposal — Buyer's Checklist

Solar proposal evaluation checklist Vibgyor Energy · use with every bidder, including us

1 · What is actually being guaranteed

Is the generation guarantee tied to irradiation? A guarantee expressed as flat annual units is a guarantee about the weather. A performance ratio guarantee holds the contractor to the plant’s efficiency against the sunlight that actually arrived — which is the only part they control.
What happens if it underperforms? Ask for the remedy in writing. Liquidated damages with a stated formula and cap are a commitment; a promise to “investigate and rectify” is not.
Is there a performance bank guarantee, and for how long? A PBG held through the defects liability period is what turns the warranty into something you can actually call on.
Who carries insurance during construction, and to what value? Contractor’s all-risk cover should exceed contract value, and marine, third-party and workmen’s compensation should all be named.

2 · What is on the roof in twenty-five years

How is the structure fixed, and does it penetrate the sheeting? Every penetration is a future leak. Ask what happens to your roof warranty, and who pays if it is voided.
Are walkways and fall protection included, or extra? Somebody has to clean this plant for twenty-five years. If access was not designed in, it will be improvised, and your HSE team will inherit it.
Where does the cleaning water come from? A plumbed line designed at drawing stage costs little. Tankering water onto a roof for twenty-five years does not.
What is the structural design wind speed, and who certified it? Ask for the calculation, not the assurance.

3 · Who is actually doing the work

Are the site crews employed, or subcontracted? A subcontract chain is where schedule and safety standards quietly diverge from what was promised in the meeting.
Who did the yield model, and on what P-value? A P50 number is a coin flip. Proposals should state P90 and say so.
Will the same organisation still be operating the plant in year ten? Ask how much capacity they currently maintain, and how much of it they did not build themselves.
Who is your named point of contact after commissioning, and does that change?

4 · The commercial structure

Is this quoted as CAPEX, OPEX or open access, and why that one? A bidder who only offers one structure is selling what they do, not what suits your balance sheet.
On OPEX, what is the escalation and the buyout schedule? A low opening tariff with steep escalation can cost more over the term than a higher flat one. Ask for the full 25-year table.
On open access, which charges are included in the landed rate? Wheeling, transmission, cross-subsidy surcharge, additional surcharge and losses. A quote that omits them is not a landed rate.
What metering regime applies in your state, and what happens to surplus? Net metering, net billing and gross metering pay very differently for the same unit.

5 · The paperwork that stalls projects

Who obtains the DISCOM approval and the inspectorate sign-off? Get it named in scope. This is the single most common cause of a commissioning date slipping.
If you lease the premises, is the landlord’s consent secured, and what happens at exit?
Are the modules ALMM-listed, and does your project require it? Behind-the-meter captive projects generally do not — a bidder charging an ALMM premium on a captive rooftop should be asked why.
What documentation comes at handover? As-built drawings, test reports, warranty certificates, O&M manuals. Regulated sites need all of it; ask before, not after.

Nothing here is specific to Vibgyor. It is the list we would want a client to run against us, because the questions that separate a considered proposal from a cheap one are the same questions either way. If a bidder cannot answer a section, that is the answer.

How to compare three solar quotes that are not comparable.

Most solar quotes are not comparable.

1 · What is actually being guaranteed

2 · What is on the roof in twenty-five years

3 · Who is actually doing the work

4 · The commercial structure

5 · The paperwork that stalls projects

Send us twelve months of bills.