Solar financial analysis in a proposal is the math the customer uses to say yes, and the first thing that breaks when incentives, tariffs, or interconnection costs were hand-waved. East Coast jobs have more moving pieces than a simple “offset times rate.” This post is how we keep those numbers honest for installer-facing proposals in MA, RI, CT, NY, and PA.
It is not investment advice. It is a checklist so sales and engineering share one model.
Production first, then money
If the kWh are wrong, the dollars are theater. Use a site-specific layout, not a statewide capacity factor copied from a blog. Shade, azimuth, snow, and downtime around PTO all matter. A system that sits six weeks waiting for a bidirectional meter does not produce in those weeks. Rhode Island Energy even warns that meter install after completion documents can take up to three weeks on Simplified. Put delay in the sensitivity, or at least do not assume COD equals last screw.
Utility rate, not a national average
Pull the bill. Residential vs commercial, supply vs delivery, demand charges, time-of-use. Net metering rules differ:
- Massachusetts net metering and SMART are separate from National Grid’s interconnect email
- Connecticut RRES credits are not a generic net meter story; see the actual tariff the customer will sit on
- New York has net metering / Value Stack (for example Con Edison Rider R in their materials) depending on size and program
- Pennsylvania net metering sits in Chapter 75 alongside interconnection
If you cannot name the tariff, you cannot finish solar financial analysis.
Incentives without mixing them into PTO
List each line with a source:
- Federal ITC: current percentage and who is eligible, with a “confirm with their tax person” note
- SMART, RRES, NY-Sun, Pennsylvania SRECs / AEPS credits
- Local rebates if they exist and you have a program page, not a rumor
Do not add SMART income to a job that will miss the equipment or siting rules. Do not assume NY-Sun block pricing from last quarter.
Permission to operate does not pay. Incentives pay, after the program agrees you exist.
Interconnection and permit cost
Application fees are published in places you can cite: Eversource CT $200 / $500 / $1,000 by track on the Application to Connect page; Con Edison $0 at ≤50 kW and $750 above that on their interconnection page. Study and upgrade costs are not a line you should invent. Show “unknown pending screens” on commercial and large residential.
PE stamps, structural letters, and extra AHJ fees belong in the price. A solar financial analysis that ignores them makes the close look cheaper than the install.
Payback, IRR, or savings
Pick one primary metric the customer asked for. Show the assumptions under it: production, degradation, rate inflation (label it as an assumption), inverter replacement year if you model one, discount rate if you show NPV.
Do not bury a 4% utility inflation number in a footnote in 6-point type. If you use it, say it.
What we refuse to do
We will not run a solar financial analysis that assumes PTO on the install date. We will not treat a CESIR as $0 because sales hopes the screen will pass. We will not use California NEM in a Massachusetts proposal.
Athol Energy’s sales proposals work is this analysis plus a layout engineering can take into permit design. If the numbers only work when interconnection is free and instantaneous, the numbers do not work.
Sources for fee tables you can show a customer: Eversource CT Application to Connect, Con Edison interconnection, RI Energy completion (meter timing warning).
Sensitivity, not a single payback number
Show at least two cases: incentives as modeled, and incentives delayed six months. Show a case where interconnection stays on the fast track and a case where it does not, for anything near a kW cutoff. Customers can handle a range. They do not handle a bait number.
Degradation and inverter replacement are optional in a residential one-pager. They are not optional in a 25-year commercial model. If you omit them, say you omitted them.
Who owns the model after sign
If sales edits production after engineering changed the layout, the solar financial analysis in the folder is a lie. Lock the model to the issued layout, or reprint the proposal. We have seen both. Reprinting is better.
Tax and accounting
ITC eligibility, depreciation, and pass-throughs are CPA work. A solar financial analysis can show an ITC percentage assumption. It should not tell a dentist they “will get” a number. Write “illustrative.” That word is not decoration.
If a partner wants Athol to run the model, send the bill PDF, the layout, and the state. We will not fill gaps with national averages.