State analysis · source documents checked 2026-09-24
Solar payback in Massachusetts (MA) — 2026
Massachusetts SMART 3.0 pays for production over time; qualification and the start of payments must be modeled separately from the installation price.
What decides the answer in Massachusetts
MassCEC's June 10, 2026 SMART 3.0 guide describes a flat incentive for systems of 25 kW or smaller: 3 cents/kWh for the 2026 base rate and 6 cents for qualifying low-income customers, locked in for 20 years once the system qualifies. SMART is open to customers of Eversource, National Grid and Unitil; a home served by a municipal light plant is not eligible. The guide says residents are eligible if they have not previously received incentives under SMART or the Renewable Portfolio Standard (RPS) and started on-site construction of a solar system on or after June 20, 2025. Joining SMART assigns the system's renewable energy certificates (RECs) to the utility for the participation term. The alternative the guide describes is selling Class I RECs yourself through your contractor or an aggregator, at market prices that can rise or fall, so compare a SMART quote and a REC-sale quote on the same production. [1] [2]
For National Grid's Massachusetts Electric and Nantucket Electric territories, the payment tariff is M.D.P.U. 1644, issued June 10 and effective July 1, 2026. It covers systems that received their Final Statement of Qualification from DOER on or after October 15, 2025. Appendix A lists the 2026 flat rates for 25 kW AC or smaller, section 7.3 fixes that rate when the system receives its Final Statement of Qualification, and section 11 runs the 20-year term from the Incentive Payment Effective Date. The MassCEC guide says payments need a utility payment mechanism approved by the Department of Public Utilities and that DOER expects resolution in 2026. The tariff text does not cite an approval order, and none was located for this page, so confirm your payment start date with National Grid. Eversource and Unitil SMART 3.0 payment tariffs were not checked here. [2] [1]
Massachusetts also has a state income-tax credit. M.G.L. chapter 62, section 6(d) gives an owner or tenant who lives in the home as a principal residence a credit of fifteen per cent of the net expenditure on renewable energy source property, or 1,000 dollars, whichever is less. Net expenditure is the cost after any federal tax credit or HUD grant received. A credit larger than the year's tax due can be carried over to the next three taxable years. At the illustrative 22,400-dollar installed cost below, 15% is 3,360 dollars, so the 1,000-dollar cap sets the amount. Only the conditional tax-credit row below includes this credit, as 1,000 dollars at the end of year 1 with no SMART payments; the no-incentive and SMART rows leave it out. The SMART rows apply the published base rate to modeled production, with receipts added at year end; the delayed case shifts the same 20 annual receipts one year later and does not pay the incentive twice. Keep the no-incentive result next to any enrolled or tax-credit case when comparing quotes. [3] [2]
How Massachusetts pays for an exported kilowatt-hour
Net metering, subject to eligible charges and surplus settlement. Net-metering bill credits and SMART payments are separate. The retail-valued energy rows assume sufficient eligible offsets; no monthly credit cap or utility bill minimum is simulated. The household rows use an assumed round 30-cent import price, slightly above the 29.35-cent EIA 2024 Massachusetts residential average and not a utility rate schedule. That is the only reason the no-incentive household row (about 7.3 years) pays back sooner than the retail benchmark (about 7.5 years); at 29.35 cents the two match. The assumed below-retail row tests exports worth less than retail.
MassCEC SMART 3.0 consumer guide — Rates, 20-year lock-in, utility and construction eligibility, REC assignment and the DPU payment-mechanism caveat.
Document: June 10, 2026 guide; Your Incentive Rate, Receiving Payments, Eligibility, SMART 3.0 vs. the REC market. Effective/source period: 2026 program-year rates; guide dated June 10, 2026 and still says payments await a DPU-approved payment mechanism.
Applies to: Qualifying <=25 kW customers of Eversource, National Grid and Unitil; municipal-light-plant customers excluded. Relevant passage: “In 2026, the base incentive rate is $0.03 per kilowatt-hour (kWh). Low-income qualified customers will receive a higher rate of $0.06 per kWh.”.
National Grid SMART 3.0 tariff — Published National Grid payment tariff, 2026 flat rates, rate fixing at qualification and term start.
Document: M.D.P.U. 1644; sections 1.0, 6.3, 7.3, 11 and Appendix A. Effective/source period: July 1, 2026; issued June 10, 2026; no DPU approval order cited in the tariff text.
Applies to: Massachusetts Electric/Nantucket Electric SMART 3.0 units with a DOER Final Statement of Qualification on or after October 15, 2025; flat rate <=25 kW AC. Relevant passage: “All SMART 3.0 STGUs will be eligible to receive compensation under this tariff for 20 years from the STGU’s Incentive Payment Effective Date.”.
M.G.L. c.62 §6(d) — Credit rate and cap, net-expenditure definition and three-year carryover.
Document: General Laws Part I, Title IX, Chapter 62, Section 6, subsection (d). Effective/source period: Codified text retrieved September 24, 2026; no new effective date asserted.
Applies to: Owner or tenant occupying Massachusetts residential property as a principal residence. Relevant passage: “a credit equal to fifteen per cent of the net expenditure for a renewable energy source property or one thousand dollars, whichever is lesser”.
“Source documents checked 2026-09-24” means each linked document was retrieved on that date and the passage quoted under it is the text the claims in this section rely on. The date covers only those claims. It is not a household eligibility decision or a guarantee that a tariff is still current, so check the linked live documents before signing a contract, and report corrections via the contact page.
Common retail-value benchmark — not a household forecast
No incentives; every modeled kWh is valued at the historical state-average retail price. The household scenarios below separate assumed import/export prices, consumption share, cash cost and receipt timing.
How Massachusetts compares with the other 50 records in this dataset
Measure
Massachusetts
Dataset median
Rank of 51
Avg residential rate
29.35¢/kWh
14.91¢/kWh
3rd highest
NSRDB daily sunlight (one location per state)
4.7 kWh/m²/day
4.9 kWh/m²/day
34th highest
Retail benchmark payback
7.5 years
13.0 years
3rd fastest on this benchmark
Household scenarios below (range)
6.8 years to 8.7 years
—
Not ranked across states
The rank compares every state on the same full-retail basis; it is a benchmark, not a forecast for a new Massachusetts customer. The household scenarios below, each with its own stated import price, export credit, cost and incentive timing, give 6.8 years to 8.7 years.
Rate: Calendar year 2024 annual average, from the EIA. Sunlight is NSRDB data via NLR PVWatts v8 at each state's 2020 Census center of population, one location per state (request settings and the values PVWatts returned are in state-insolation-pvwatts.json). Ranks and medians are computed across the 50 states and DC in this dataset. Every input behind the payback figure is printed in the assumptions block below, and the full 51-row table is at /states.
Reproduce the Massachusetts household comparisons
These are hypothetical households, not customer results or offers. All start from an assumed 7 kW array producing 9406.49 kWh in year one; any row that changes production (a battery or a production-stress row) says so. The sunlight input is NSRDB data via PVWatts v8 for one location per state (request and response in state-insolation-pvwatts.json; see the methodology), not a production estimate for your roof. No federal credit is applied. No loan, income-tax effect on incentive revenue, battery replacement or future tariff change is modeled.
The benchmark row prices every kWh at the EIA average cited above. Where another row applies a published figure (for example a tariff or rider rate or charge, a program incentive rate, a statutory fee schedule, or a tax credit's rate, cap or carryforward period), that figure comes from a document in the sources list above. Every other price, consumption share, cost, fee, receipt date and amount of tax a household can use in a year is assumed. Eligibility remains conditional. The annual split does not reproduce monthly netting, time-of-use periods, credit caps, curtailment or minimum bills. Annual fees represent incremental solar costs, not charges you would pay with or without solar.
Production degrades by assumed 0.5% per year. The main result increases both import and export prices by assumed 3% per year; the flat-price column sets that to zero. Neither escalation is a tariff forecast. Fixed fees and scheduled receipts do not escalate. Energy savings accrue uniformly within a year for interpolation; incentives arrive only at year end.
Modeled results, not guarantees. No break-even means no crossing inside 25 years, not a calculated date beyond year 25.
Scenario
Initial cash cost
Year 1 energy value
Year 1 net cash incl. receipts
Payback
Flat-price payback
25-year net cash after cost
Common retail-value benchmark — no incentives
$22,400.00
$2,760.80
$2,760.80
7.5 years
8.3 years
Modeled $71,719.90
Hypothetical household — no incentives
$22,400.00
$2,821.95
$2,821.95
7.3 years
8.1 years
Modeled $73,804.33
Illustrative higher cash price — no incentives
$26,880.00
$2,821.95
$2,821.95
8.7 years
9.7 years
Modeled $69,324.33
Conditional production incentive — year-end receipts
$22,400.00
$2,821.95
$3,104.14
6.8 years
7.4 years
Modeled $79,188.01
Conditional production incentive — receipts delayed one year
$22,400.00
$2,821.95
$2,821.95
6.9 years
7.5 years
Modeled $79,188.01
Conditional state income-tax credit (1,000 dollars) in year 1 — no SMART
$22,400.00
$2,821.95
$3,821.95
7.0 years
7.7 years
Modeled $74,804.33
Assumed 20% of production credited below retail — no incentives
$22,400.00
$2,445.69
$2,445.69
8.4 years
9.4 years
Modeled $60,977.08
Inputs, receipts and annual arithmetic: Common retail-value benchmark — no incentives
Historical state-average import value for ALL production; only a comparison, not an address-specific tariff.
Assumed initial cash cost $22,400.00, not reduced by any upfront credit or rebate; any receipt is listed below and arrives at year end. Import 29.350¢/kWh; export 29.350¢/kWh; self-use 100%; incremental fixed annual cost $0.00.
Year-one modeled energy value = 9406.49 × [(100/100 × 29.35/100) + ((1 − 100/100) × 29.35/100)] = $2,760.80. Subtract the annual fixed cost and add only that year's receipts for net cash. Display rounds cents; the downloadable calculation retains full precision.
Incentive basis: None; no eligibility or benefit assumed. Modeled total receipts inside 25 years: $0.00. These are not subtracted from initial cash cost.
The exact input fields and all 25 modelled years for this row are in the JSON download above.
Inputs, receipts and annual arithmetic: Hypothetical household — no incentives
Assumed round 30-cent import price, slightly above the 29.35-cent EIA 2024 Massachusetts average and not a utility rate schedule; exports are assumed to offset eligible charges at the same retail price, so the 50% self-use figure has no effect. SMART qualification and receipt start remain conditional.
Assumed initial cash cost $22,400.00, not reduced by any upfront credit or rebate; any receipt is listed below and arrives at year end. Import 30.000¢/kWh; export 30.000¢/kWh; self-use 50%; incremental fixed annual cost $0.00.
Year-one modeled energy value = 9406.49 × [(50/100 × 30/100) + ((1 − 50/100) × 30/100)] = $2,821.95. Subtract the annual fixed cost and add only that year's receipts for net cash. Display rounds cents; the downloadable calculation retains full precision.
Incentive basis: None; no eligibility or benefit assumed. Modeled total receipts inside 25 years: $0.00. These are not subtracted from initial cash cost.
The exact input fields and all 25 modelled years for this row are in the JSON download above.
Inputs, receipts and annual arithmetic: Illustrative higher cash price — no incentives
Same production, prices, consumption share and fees, but cash cost is 20% higher; not a market-price estimate.
Assumed initial cash cost $26,880.00, not reduced by any upfront credit or rebate; any receipt is listed below and arrives at year end. Import 30.000¢/kWh; export 30.000¢/kWh; self-use 50%; incremental fixed annual cost $0.00.
Year-one modeled energy value = 9406.49 × [(50/100 × 30/100) + ((1 − 50/100) × 30/100)] = $2,821.95. Subtract the annual fixed cost and add only that year's receipts for net cash. Display rounds cents; the downloadable calculation retains full precision.
Incentive basis: None; no eligibility or benefit assumed. Modeled total receipts inside 25 years: $0.00. These are not subtracted from initial cash cost.
The exact input fields and all 25 modelled years for this row are in the JSON download above.
Inputs, receipts and annual arithmetic: Conditional production incentive — year-end receipts
Published unit incentive applied only conditionally to hypothetical eligible production. Actual program payments may be monthly/quarterly; this annual model aggregates at year end and omits income-tax effects. Delay shifts the same earned receipts rather than creating an extra earning year.
Assumed initial cash cost $22,400.00, not reduced by any upfront credit or rebate; any receipt is listed below and arrives at year end. Import 30.000¢/kWh; export 30.000¢/kWh; self-use 50%; incremental fixed annual cost $0.00.
Year-one modeled energy value = 9406.49 × [(50/100 × 30/100) + ((1 − 50/100) × 30/100)] = $2,821.95. Subtract the annual fixed cost and add only that year's receipts for net cash. Display rounds cents; the downloadable calculation retains full precision.
Incentive basis: 30 dollars/MWh × modeled degraded production, 20 assumed eligible production years; 0-year receipt delay. Qualification is NOT verified. Modeled total receipts inside 25 years: $5,383.68. These are not subtracted from initial cash cost.
Assumed receipt at end of year 1: $282.19
Assumed receipt at end of year 2: $280.78
Assumed receipt at end of year 3: $279.38
Assumed receipt at end of year 4: $277.98
Assumed receipt at end of year 5: $276.59
Assumed receipt at end of year 6: $275.21
Assumed receipt at end of year 7: $273.83
Assumed receipt at end of year 8: $272.46
Assumed receipt at end of year 9: $271.10
Assumed receipt at end of year 10: $269.75
Assumed receipt at end of year 11: $268.40
Assumed receipt at end of year 12: $267.06
Assumed receipt at end of year 13: $265.72
Assumed receipt at end of year 14: $264.39
Assumed receipt at end of year 15: $263.07
Assumed receipt at end of year 16: $261.75
Assumed receipt at end of year 17: $260.45
Assumed receipt at end of year 18: $259.14
Assumed receipt at end of year 19: $257.85
Assumed receipt at end of year 20: $256.56
The exact input fields and all 25 modelled years for this row are in the JSON download above.
Inputs, receipts and annual arithmetic: Conditional production incentive — receipts delayed one year
Published unit incentive applied only conditionally to hypothetical eligible production. Actual program payments may be monthly/quarterly; this annual model aggregates at year end and omits income-tax effects. Delay shifts the same earned receipts rather than creating an extra earning year.
Assumed initial cash cost $22,400.00, not reduced by any upfront credit or rebate; any receipt is listed below and arrives at year end. Import 30.000¢/kWh; export 30.000¢/kWh; self-use 50%; incremental fixed annual cost $0.00.
Year-one modeled energy value = 9406.49 × [(50/100 × 30/100) + ((1 − 50/100) × 30/100)] = $2,821.95. Subtract the annual fixed cost and add only that year's receipts for net cash. Display rounds cents; the downloadable calculation retains full precision.
Incentive basis: 30 dollars/MWh × modeled degraded production, 20 assumed eligible production years; 1-year receipt delay. Qualification is NOT verified. Modeled total receipts inside 25 years: $5,383.68. These are not subtracted from initial cash cost.
Assumed receipt at end of year 2: $282.19
Assumed receipt at end of year 3: $280.78
Assumed receipt at end of year 4: $279.38
Assumed receipt at end of year 5: $277.98
Assumed receipt at end of year 6: $276.59
Assumed receipt at end of year 7: $275.21
Assumed receipt at end of year 8: $273.83
Assumed receipt at end of year 9: $272.46
Assumed receipt at end of year 10: $271.10
Assumed receipt at end of year 11: $269.75
Assumed receipt at end of year 12: $268.40
Assumed receipt at end of year 13: $267.06
Assumed receipt at end of year 14: $265.72
Assumed receipt at end of year 15: $264.39
Assumed receipt at end of year 16: $263.07
Assumed receipt at end of year 17: $261.75
Assumed receipt at end of year 18: $260.45
Assumed receipt at end of year 19: $259.14
Assumed receipt at end of year 20: $257.85
Assumed receipt at end of year 21: $256.56
The exact input fields and all 25 modelled years for this row are in the JSON download above.
Inputs, receipts and annual arithmetic: Conditional state income-tax credit (1,000 dollars) in year 1 — no SMART
M.G.L. c.62 §6(d) allows an owner or tenant who occupies the home as a principal residence “a credit equal to fifteen per cent of the net expenditure for a renewable energy source property or one thousand dollars, whichever is lesser”; a credit larger than the year's tax due may be carried over. Fifteen per cent of the assumed 22,400-dollar cash price is 3,360 dollars, so the cap applies. Assumes the whole credit is used on the first return.
Assumed initial cash cost $22,400.00, not reduced by any upfront credit or rebate; any receipt is listed below and arrives at year end. Import 30.000¢/kWh; export 30.000¢/kWh; self-use 50%; incremental fixed annual cost $0.00.
Year-one modeled energy value = 9406.49 × [(50/100 × 30/100) + ((1 − 50/100) × 30/100)] = $2,821.95. Subtract the annual fixed cost and add only that year's receipts for net cash. Display rounds cents; the downloadable calculation retains full precision.
Incentive basis: Assumed usable credit: min(15% × cash price, 1,000 dollars) = 1,000 dollars at year-one end; residency and tax liability not verified. Modeled total receipts inside 25 years: $1,000.00. These are not subtracted from initial cash cost.
Assumed receipt at end of year 1: $1,000.00
The exact input fields and all 25 modelled years for this row are in the JSON download above.
Inputs, receipts and annual arithmetic: Assumed 20% of production credited below retail — no incentives
Hypothetical stand-in for exports that the bill cannot absorb or that fall outside net-metering eligibility: 80% of production keeps the assumed 30-cent retail value and 20% earns an assumed 10 cents. Neither the share nor the 10 cents is a Massachusetts tariff value. In this row the self-use field means the share credited at retail.
Assumed initial cash cost $22,400.00, not reduced by any upfront credit or rebate; any receipt is listed below and arrives at year end. Import 30.000¢/kWh; export 10.000¢/kWh; self-use 80%; incremental fixed annual cost $0.00.
Year-one modeled energy value = 9406.49 × [(80/100 × 30/100) + ((1 − 80/100) × 10/100)] = $2,445.69. Subtract the annual fixed cost and add only that year's receipts for net cash. Display rounds cents; the downloadable calculation retains full precision.
Incentive basis: None; no eligibility or benefit assumed. Modeled total receipts inside 25 years: $0.00. These are not subtracted from initial cash cost.
The exact input fields and all 25 modelled years for this row are in the JSON download above.
Formula and modeling limitations · Use the editable calculator below to test your own cash price and energy split. It cannot confirm utility enrollment or tax eligibility.
Assumptions behind the Massachusetts retail-value benchmark
A common full-retail comparison, not an address-specific forecast. Size alone does not change payback when cash cost and production both scale proportionally. Use the worksheet to vary cash price, production, self-consumption, export value and recurring costs.
System modeled
7 kW DC
Assumed installed cost
$22,400 (assumed $3.20/W DC)
Annual production, year 1
9,406 kWh
Production basis
NSRDB daily sunlight on a 20° south-facing panel at Massachusetts's 2020 Census population center (4.72 kWh/m²/day, via PVWatts v8). Annual production = system kW × this input × 365 × assumed performance ratio. PVWatts' own modelled AC output for the same request is 1,304.7 kWh per kW, or 9,133 kWh for 7 kW, so this shortcut runs 3.0% above it; on the PVWatts figure the benchmark payback would be 7.7 years.
Performance ratio (system losses)
0.78
EIA state-average retail rate
29.35¢/kWh — Calendar year 2024 annual average
Panel degradation
0.5%/yr
Assumed electricity price escalation
3.0%/yr, not a forecast
Model horizon
25 years
Federal tax credit applied
None included in this benchmark
State or utility incentives applied
None deducted in this benchmark. Where a household scenario above applies a published tariff rate or a conditional receipt, its row says so; this benchmark applies none of them
Assumed value of all production
Full retail rate, including exports; not a utility tariff lookup
Recurring operating costs applied
None in this benchmark; editable in worksheet
How the payback figure reconciles
Modelled $22,400 ÷ modelled $2,761 of year-one savings = 8.1 years — the straight division, if electricity prices never move and the panels never age.
With 0.5%/yr degradation and prices held flat: 8.3 years.
With the same degradation and electricity prices rising 3.0%/yr: 7.5 years — the retail-value benchmark, not a household forecast.
Production stress test, same assumed prices: 20% less production (shading, a poorer roof angle) gives 9.2 years; 20% more production gives 6.3 years. This is a what-if range, not a confidence interval.
These price-growth rates are assumptions, not forecasts of your utility's tariff. None of these cases models financing, taxes, battery dispatch or actual utility settlement. No crossing within 25 years does not establish a crossing later. Full wording on the methodology.
Solar cash-flow worksheet
Compare assumed cash flows, not an address-specific forecast. No tariff, roof or incentive eligibility is looked up. Your worksheet entries are calculated in this browser; the worksheet does not send them anywhere or save them between visits. The site also loads Google advertising code; the privacy page explains what that code may collect and your choices.
Starting retail rate: 29.35¢/kWh — Calendar year 2024 annual average (Massachusetts), from EIA Table 2.10. It is not your current tariff. All cost, export, usage, escalation and incentive entries are assumptions.
With no incentives or recurring costs, fixed cost/W and proportional generation mean that increasing size scales cost and savings equally: payback years cancel out. Unedited price and production follow that rule here. Once you edit either, it stays fixed when size changes; update it deliberately. Different cash prices, shading/production and export shares can change payback.
Optional assumed cash incentives — zero by default
No federal, state or utility incentive is inferred. Check eligibility and actual receipt timing. Recurring and delayed incentives arrive at year end; do not enter the same benefit in multiple fields. Operating cash is approximated uniformly within each year.
Your entered scenario — modelled, not a quote
Modelled installed cash price
$22,400
Modelled initial outlay after upfront rebate
$22,400
Modelled year-one net cash, including receipts/costs
$2,761
Modelled first cash-flow break-even
7.5 years
Modelled 25-year net cash after initial outlay
$71,720
Modelled production in year one
9,406 kWh
Modelled year-one energy value before costs/incentives: $2,761.
No break-even inside 25 years means the model never crosses within its horizon; it does not predict a later crossing. This is undiscounted cash flow, not investment return. A first crossing can reverse if later operating costs exceed cash benefits. Financing, taxes, changing export rules, time-of-use settlement, credit expiry and battery dispatch are not simulated.
Assumed price-escalation sensitivity
Same entered inputs, degradation and nominal fixed costs; only import/export price escalation changes. These are scenarios, not forecasts.
0%/year: 8.3 years
3%/year: 7.5 years
6%/year: 6.9 years
Separate common retail-value benchmark
This comparison uses 7 kW, assumed $3.20/W, production from the state's one-location NSRDB sunlight input and 29.35¢/kWh (Calendar year 2024 annual average) for every kWh. It ignores your entered cash price, production, tariff, costs and incentives; assumes 0.5% degradation and 3% escalation. It is not an address forecast.
Benchmark assumed cash price
$22,400
Benchmark modelled year-one value
$2,761
Benchmark modelled break-even
7.5 years
Reproduce the 25-year modelled cash flows for your entered scenario
Annual cash = degraded production × weighted import/export price × price-escalation factor − annual fixed cost + eligible year-end receipts. Cumulative cash starts at negative initial outlay. Incentives after year 25 are excluded.
Use your utility tariff and a site-specific production assessment to refine inputs. Methodology and limitations.
Estimate only. State comparisons are common retail-value benchmarks, not forecasts for your roof. Custom scenarios depend on the cash price, production, import/export prices, self-consumption and other assumptions entered. They are not quotes or guarantees. Listed incentives do not establish eligibility or a payment date. The Residential Clean Energy Credit (Section 25D, the 30% federal tax credit) expired for systems placed in service after December 31, 2025. Verify all numbers with a licensed installer and your utility before making a purchase decision. See full disclaimer.
Compare every state
Massachusetts is one of 17 jurisdictions with a written analysis on this site: 16 states and the District of Columbia. The rate, sunlight, modeled payback and recorded incentives for all 50 states and DC — including those without a page — are in one sortable table.