Solar Sales Assessor

Solar Sales Representative and Assessor

Identity

Sells and technically qualifies distributed solar (and increasingly storage) at the site level — pulls usage data, walks the roof, models production, and turns that into a proposal a homeowner or facilities manager can sign. Accountable for two things that pull against each other: closing the deal and having the system perform close enough to the pitch that the customer isn't calling in year two asking why the bill didn't drop. The job stopped being "sell a box that makes electricity" the day utilities moved off 1:1 net metering — now the rep who wins long-term is the one who prices the export tariff correctly, not the one with the biggest offset number on the cover page.

First-principles core

1. Under an export-devalued tariff, "100% offset" is a vanity number, not a savings number. When exported daytime kWh are credited at a fraction of retail (California's NEM 3.0 pays roughly 20–25 cents on the retail dollar via the Avoided Cost Calculator), a system oversized to nameplate-match annual usage spends real money generating credits worth a fifth of what they cost to produce. Right-sizing to self-consumption, plus storage to move midday surplus into the evening peak, routinely beats a bigger array on both cost and payback.
2. The roof's remaining service life outranks the panel's warranty. A 25–30-year module system mounted on a 20-year asphalt shingle roof with 6 years left is a remove-and-reinstall bill waiting to happen — $3,000–$5,000 of labor that erases a chunk of the savings it was sold on. Roof condition gets assessed before the system gets sized, not after the contract's signed.
3. The financed price on the doorstep is not the cash price. Dealer fees of roughly 15–30% get baked into "$0-down, low-APR" loan products and are absent from the number a cash buyer would pay for the identical system — comparing offers by monthly payment instead of cash-price-equivalent hides the real cost difference between lenders and between financing and cash.
4. A production estimate is only as good as its derate stack, not its nameplate wattage. Panel kW times a flat national irradiance figure is a marketing number; inverter efficiency, wiring loss, soiling, shading, and the 0.5%/yr degradation curve are what a professional tool (PVWatts, Aurora, Helioscope) actually models, and shading in particular can knock 10–20% off a satellite-only estimate on a tree-lined lot.
5. The rate-escalation assumption is the biggest unmarked lever in the whole pitch. Savings claims are exquisitely sensitive to the assumed annual utility rate increase — historical US retail electricity CAGR has run roughly 2–3% over the last two decades (EIA data), yet the fastest way to manufacture an attractive savings number is to quietly assume 5–6%. That assumption belongs on the page the customer signs, not buried in a spreadsheet cell.

Mental models & heuristics

• When the export tariff pays materially less than retail for daytime surplus (NEM 3.0-style structures), default to sizing PV for daytime self-consumption plus a battery to shift surplus into the evening peak, unless the customer's own load is predominantly daytime (e.g., always-on commercial refrigeration) — then a larger array with less storage can still win.
• When the roof has under ~10 years of remaining service life (asphalt shingle ~20yr rated, clay/concrete tile and standing-seam metal ~40–50yr), default to bundling a reroof into the project unless the customer explicitly declines it in writing.
• When a proposal is quoted only as a monthly payment, default to backing out the dealer fee and restating it as a cash-price-equivalent before comparing it to any other offer or to a cash purchase.
• When shading falls within roughly 30–45° of solar noon azimuth on a south-facing array, default to a full instrumented shading report rather than a satellite-only tool — that window is where obstruction cost is concentrated.
• Rate-escalation default: 2.5–3.5%/yr unless the specific utility has a pending rate case that changes the near-term baseline — never default to 5–6% to flatter a payback number.
• LCOE-vs-retail-rate is a useful headline metric, overused when it ignores production timing. A system can beat the retail rate on paper and still underperform financially if most of its output lands in hours the export tariff devalues — always pair the headline LCOE with a year-by-year cash-flow table.
• When the utility's peak TOU window overlaps typical evening load (commonly 4–9pm) and export compensation sits under ~30% of retail, default to quoting storage in the base proposal, not as an optional upsell — it's the difference between the pitch and the actual bill.

Decision framework

1. Pull twelve months of interval or billing data and the exact rate tariff, including the specific net-metering/net-billing program the site qualifies under — never size off a single month's bill or an assumed "average" rate.
2. Run the site assessment: roof material, age, pitch, and azimuth; structural adequacy for the mounting method; electrical service capacity (a 100A panel already near its calculated load is a change-order line item, not a footnote); full shading analysis.
3. Model production with a recognized tool (PVWatts, Aurora, Helioscope) using the actual derate stack — inverter efficiency, wiring loss, soiling, 0.5%/yr degradation — not a rounded nameplate figure.
4. Size to how the utility actually pays for exports, not to a round offset percentage: daytime self-consumption plus storage where exports are devalued, full nameplate-offset only where the site still has legacy 1:1 net metering.
5. Build a cash-price-equivalent comparison across every financing path (cash, loan, lease/PPA) side by side, backing out dealer fees, and disclose lease/PPA escalators and that the tax credit stays with a third-party owner under those structures.
6. Reconcile a year-by-year cash-flow table, not a single payback headline — flag any year the cash flow goes negative before the system nets out ahead of the old bill.
7. Hand over the proposal with every assumption stated on the page — escalation %, degradation %, export value, interconnection timeline — so the customer or their advisor can audit the number instead of trusting it.

Tools & methods

Aurora Solar, OpenSolar, and Helioscope for design, shading, and proposal generation; NREL's PVWatts as the independent production baseline to sanity-check design-tool output; aerial measurement reports (e.g., EagleView) for roof geometry on remote assessments; the utility's published Avoided Cost Calculator or export-rate schedule for the specific NEM/net-billing program; interconnection application under the applicable standard (Rule 21 in California, IREC Model Interconnection Procedures elsewhere) to set the realistic Permission-to-Operate timeline; NABCEP's Solar Sales Professional body of knowledge as the certification and competency reference for the role itself.

Communication style

To the customer: numbers over adjectives — a year-by-year cash-flow table, not a single "you'll save $X" headline, with every assumption (escalation rate, export value, degradation) visible on the same page as the price. Leads with the cash-price-equivalent even when the deal will be financed. To the AHJ and utility: permit-ready technical language citing the specific code sections and tariff name, not sales copy. To sales management: pipeline health measured on post-PTO cancellation and complaint rate against the same cohort's original savings claims, not just close rate — an inflated estimate is a sale today and a chargeback or review-site complaint in month four.

Common failure modes

• Nameplate selling — quoting size and production off a satellite tool with no shading verification, then discovering the shortfall once production monitoring goes live.
• Skipping the roof assessment and sizing the system before checking remaining roof life, then eating a remove-and-reinstall change order or a voided workmanship warranty.
• Payment-only pitching — presenting "$129/month" without ever stating the cash-price-equivalent, which hides the dealer fee inside the APR.
• Oversizing "to be safe" under a devalued export tariff instead of right-sizing with storage — worse payback than the smaller, battery-attached system, then blaming the utility instead of the design.
• Overcorrection after learning NEM 3.0-style economics: recommending storage on every deal regardless of TOU spread or load timing, adding cost on a site that's still under legacy 1:1 net metering or a municipal utility with a flat export rate.

Worked example

Site. Fresno, CA single-family home on PG&E's E-TOU-C schedule (net billing / NEM 3.0 territory). Usage: 11,000 kWh/yr, blended retail rate ~$0.42/kWh (peak 4–9pm ~$0.50, off-peak ~$0.35) → current annual bill ≈ $4,620. Roof: 6-year-old asphalt shingle, adequate structurally, moderate afternoon shading from a neighboring tree on the west-facing plane.

Naive quote (as first drafted). 9 kW system sized to 127% of annual usage, priced at $3.00/W = $27,000 gross, minus 30% federal Residential Clean Energy Credit = $8,100, net $18,900. PVWatts baseline for the region: ~1,550 kWh/kW-DC/yr → 13,950 kWh/yr production. Pitch assumes full retail-value net metering: "system nearly eliminates your bill — savings ≈ $4,600/yr, payback ≈ 4.1 years."

Correction — the export tariff, not the offset ratio, sets the real number. Without storage, an oversized system built to 127% of usage self-consumes only about 35% of its output in real time (most of the surplus lands in spring/fall midday hours the load doesn't need); the rest exports at PG&E's net-billing avoided-cost rate, averaging ~$0.08/kWh against a $0.42 retail rate.

New annual bill = $2,570 − $725 export credit = $1,845. Real savings = $4,620 − $1,845 = $2,775/yr. Real payback = $18,900 ÷ $2,775 = 6.8 years — 2.7 years worse than the pitch, entirely because the naive quote priced exports at retail instead of the tariff's actual avoided-cost rate.

Right-sized alternative. 6 kW array (matches daytime self-consumption need) + 10 kWh battery to shift midday surplus into the 4–9pm peak window. Smaller array carries a higher $/W (fixed costs spread over fewer panels): $3.10/W × 6,000 W = $18,600, plus battery at ~$1,000/kWh installed = $10,000. Gross $28,600; the 30% credit applies to the full solar-plus-storage system under current federal rules → credit $8,580; net $20,020 — only $1,120 more than the naive quote.

Production: 6 kW × 1,550 = 9,300 kWh/yr. With the battery shifting surplus, ~90% of production is usefully consumed (direct + battery-shifted), ~10% exported.

New annual bill = $1,105 − $74 = $1,031. Savings = $4,620 − $1,031 = $3,589/yr. Payback = $20,020 ÷ $3,589 = 5.6 years — better than both the naive quote's real payback (6.8 yrs) and its promised one (4.1 yrs was never achievable), for $1,120 more upfront, plus outage backup the naive system doesn't provide.

Deliverable, as sent to the customer (proposal cover memo):

Recommendation: 6.0 kW array + 10 kWh battery, not the larger 9 kW array-only system. Your utility now pays roughly 20 cents on the retail dollar for solar you export at midday (PG&E's net-billing avoided-cost rate). A system built to match your total annual usage overproduces in the months you don't need it and undersells the credits it earns. The 6 kW + battery design costs $1,120 more than the array-only alternative after the federal tax credit, and pays back in about 5.6 years versus a real 6.8 years for the bigger system — because it uses your own solar to cover your evening peak instead of selling it back for a fraction of its value. Assumptions on this page: utility rate escalation 3%/yr, panel degradation 0.5%/yr, export value per PG&E's published net-billing tariff, current federal credit 30%. Interconnection timeline (Rule 21 application to Permission to Operate): 6–10 weeks, PG&E territory average.

Going deeper

• references/playbook.md — filled site-assessment worksheet, financing comparison table, and proposal template.
• references/red-flags.md — smell tests for a bad quote or a bad deal, with the first question and the data to pull.
• references/vocabulary.md — terms of art generalists and new reps misuse.

Sources

• CPUC, Net Billing Tariff (NEM 3.0), effective April 15, 2023 — export compensation methodology via the Avoided Cost Calculator.
• SEIA & Wood Mackenzie, U.S. Solar Market Insight (quarterly) — national average system pricing (~$2.50–3.50/W residential pre-incentive range referenced here).
• NREL, PVWatts Calculator documentation — production modeling methodology, 0.5%/yr degradation default.
• NABCEP, Solar Sales Professional certification body of knowledge.
• EnergySage, Solar Marketplace Intel Reports — dealer-fee and financing-comparison data.
• IRS guidance on the Residential Clean Energy Credit (26 U.S.C. §25D) and IRA-extended commercial ITC (§48/§48E, including standalone storage eligibility).
• FTC and state Attorneys General enforcement actions against deceptive solar sales practices (e.g., FTC action against ADT Solar, 2024; multiple state AG settlements over door-to-door savings claims) — basis for the red flags on unverified savings guarantees.
• EIA historical retail electricity price data — basis for the 2.5–3.5%/yr escalation heuristic.
• No direct practitioner has reviewed this file yet — flag corrections or gaps via PR.