Answer
Audit a solar proposal by tracing each financial conclusion to its scenario inputs: usage, tariff, generation model, price, operating costs, financing and incentives. Identify the source and date of each input, label assumptions, reconcile versions and have the responsible reviewer check the result. A precise output can still rest on an uncertain assumption.
A savings figure is difficult to review when the proposal does not show which bill, tariff or design scenario produced it. Start with the customer’s decision, then trace the financial result back to its inputs.
This checklist organizes a review; it does not calculate returns, establish incentive eligibility or recommend a financial product. The relevant technical, commercial, tax and financial owners must assess the actual project and market.
Name the question the scenario answers
A cash purchase comparison and a financed payment comparison are different decisions. Identify the scenario, customer, site, design revision and time basis before reviewing its conclusion. State which alternatives the proposal includes and why.
Ask the model owner to define each displayed measure. A label such as “savings” should not leave the reader guessing whether financing payments, operating costs or other items are included.
Build the assumption register beside the model
| Input family | Record to inspect | Question for the owner |
|---|---|---|
| Consumption | Source bills or interval data, coverage period | What is measured, missing or projected? |
| Tariff and export treatment | Applicable published schedule and customer context | Which rules and effective dates were used? |
| Generation | Model run and matching design revision | Does this result belong to the proposed system? |
| Purchase and operating costs | Current quote and stated allowances | Which costs or future replacements are excluded? |
| Financing | Applicable written offer or explicitly hypothetical terms | Which fees, payments and conditions are included? |
| Incentives | Current official program evidence | What eligibility or payment conditions remain unresolved? |
| Future changes | Named assumptions and calculation basis | Which conclusions depend on a forecast? |
Do not fill a missing source with an unlabelled default. Record the gap and ask which result it could affect.
Keep measured inputs separate from scenarios
A historic bill is evidence of a past period, not proof of future consumption. Label planned loads and other future changes as assumptions. Record who supplied them and whether the proposal is showing a comparison or making a commitment.
Where uncertainty matters to the decision, ask the model owner to show an alternative assumption using the same definitions. Do not invent a sensitivity range because it looks conventional. Explain why the selected alternatives are relevant to this customer.
Reconcile the financial result with the design revision
Check the layout, equipment and production result against the scenario named in the proposal. If the design changed, ask which financial inputs and outputs need to be recalculated and reviewed.
NASA’s configuration-management guidance describes controlling changes and keeping product information consistent. This is a limited process analogy; it does not validate a solar financial model or its assumptions.
Illustrative example: a proposal receives a revised layout image while its savings table remains attached to the previous production case. Hold the affected conclusion, reconcile the source revisions and obtain a new review before presenting the table as the current scenario.
Put conditions where the customer interprets the result
Place material assumptions beside the corresponding financial claim, not only in a distant disclaimer. Identify unresolved eligibility, quoted-term validity and excluded costs in language the customer can understand.
Ask the release reviewer to read the heading and headline number without the explanatory paragraphs. If that reading suggests certainty the evidence does not support, revise the presentation.
Record the final review
Keep the scenario identifier, input sources, calculation version, unresolved conditions, reviewer decisions and exact sent output. A signed-off form is useful only if the reviewer can identify what was reviewed.
When evaluating SurgePV’s financial modeling workflow, ask to trace one displayed result back to its inputs and assumptions. Confirm what the current product exposes and what your team must document separately.
Frequently asked questions
Does a detailed financial table prove the proposal is accurate?
No. Review the input sources, definitions, calculation basis and scenario revision. Detailed formatting does not establish that the inputs apply to the customer or that the displayed measure includes the costs the reader expects.
What if an incentive has not been confirmed?
Keep the uncertainty visible and obtain current official evidence and appropriate review. Do not present an unconfirmed benefit as guaranteed cash or silently include it in a base scenario that the customer may treat as certain.
Which change should trigger another financial review?
Ask the model owner whenever an input or condition underlying the conclusion changes, including the design case, usage assumption, tariff, commercial quote or financing terms. Record which outputs were affected and reviewed again.
Sources
Primary research and reference material used for this desk-research article.
Where this fits
This article is part of SurgePV's Solar Business & Operations hub, which works through the topic from first principles to the decisions a project team actually has to make.
