Loading NuWatt Energy...
We use your location to provide localized solar offers and incentives.
We serve MA, NH, CT, RI, ME, VT, NJ, PA, and TX
Loading NuWatt Energy...
MA utility TOU rates change everything. Eversource off-peak is just $0.08/kWh -- so the question is not just "how many panels" but "when should you charge?" Interactive calculator, utility-specific math, and SMART 3.0 + ConnectedSolutions stacking.
Most solar sizing guides assume you need enough panels to cover all EV charging. In Massachusetts, utility TOU rates make the math more nuanced -- and potentially save you thousands.
Typical EV at off-peak: ~$288/year. That is 72% cheaper than the standard $0.28/kWh rate ($1,008/year).
Typical EV at off-peak: ~$540/year. Still 53% cheaper than the standard $0.32/kWh rate ($1,152/year).
If you are on Eversource TOU charging off-peak at $0.08/kWh, your annual EV charging cost is only $288. Adding 6-7 solar panels at $4,000-$5,000 to eliminate that $288/year cost gives a 14-17 year payback on the EV-specific panels alone. The real value of additional solar is offsetting your home electricity at $0.28-$0.38/kWh on-peak -- not your cheap off-peak EV charging. A smarter strategy: size your solar to offset your entire home load, let net metering credits cover EV charging, and charge off-peak.
Assumes a typical EV driven 12,000 miles per year at 30 kWh/100mi (3,600 kWh/year). MA-specific utility rates as of March 2026.
| Charging Scenario | Rate | Annual Cost | Extra Panels | Upfront Cost | Notes |
|---|---|---|---|---|---|
| Grid Off-Peak (Eversource TOU) | $0.08/kWh | $288 | 0 | $0 | Cheapest per-kWh. Charge 11 PM-7 AM. |
| Grid Off-Peak (National Grid TOU) | $0.15/kWh | $540 | 0 | $0 | Still cheaper than standard rate. |
| Grid Standard Rate (Eversource) | $0.28/kWh | $1,008 | 0 | $0 | Default rate if no TOU enrollment. |
| Grid Standard Rate (National Grid) | $0.32/kWh | $1,152 | 0 | $0 | Highest per-kWh annual cost. |
| Solar Direct (Midday Charging) | $0.00/kWh | $0 | 6-7 | $4,000-$5,000 | $0 fuel cost. Best for WFH. |
| Solar + Battery (Overnight) | $0.00/kWh | $0 | 6-7 | $16,000-$17,000 | Store solar, charge overnight. CS revenue offsets. |
Eversource TOU off-peak at $0.08/kWh. Just $288/year. No extra panels needed. Enroll in the R-2 rate plan.
If your car is home during the day, charge directly from solar. 6-7 panels, $0/year in fuel, and net metering credits the surplus.
Solar + battery stores daytime energy for overnight EV charging. $0 fuel + ConnectedSolutions revenue ($1,350-$1,850/yr) offsets battery cost.
Here is the step-by-step formula using MA-specific sun hours and panel output data. No hidden assumptions.
Example: Typical EV at 12,000 mi/yr x 30 kWh/100mi = 3,600 kWh/year
Example: 440W panel in MA: (440 x 4.2 x 365 x 0.85) / 1,000 = 573 kWh/yr
Example: Round up to 7 panels. That is a 3.08 kW addition to your system.
Massachusetts averages 4.2 peak sun hours per day (NREL PVWatts data for Boston). This is slightly above the New England average (4.0) due to coastal exposure. Cape Cod and the South Shore get closer to 4.3, while the Berkshires average 3.9. We use 4.2 as the statewide representative value.
Select your EV model and annual miles. Set the region to "Boston, MA" for accurate Massachusetts output. The calculator shows panels needed, system cost, and fuel savings.
How many panels do you need to charge your EV from solar?
Assumes 27 MPG for comparable gas vehicle, $3.50/gal gasoline, 85% system derating factor
Based on 12,000 miles/year, 4.2 peak sun hours (Boston), and 440W panels. Annual charging costs shown for Eversource TOU off-peak vs standard rate.
| EV Model | 440W Panels | Annual kWh | TOU Off-Peak | Standard Rate |
|---|---|---|---|---|
| Tesla Model 3 LR | 5 | 3,000 | $240/yr | $840/yr |
| Tesla Model Y LR | 6 | 3,240 | $259/yr | $907/yr |
| Tesla Model X | 7 | 3,960 | $317/yr | $1,109/yr |
| Chevy Equinox EV | 6 | 3,480 | $278/yr | $974/yr |
| Ford Mustang Mach-E | 7 | 3,600 | $288/yr | $1,008/yr |
| Ford F-150 Lightning | 10 | 5,760 | $461/yr | $1,613/yr |
| Hyundai Ioniq 5 | 6 | 3,480 | $278/yr | $974/yr |
| Hyundai Ioniq 6 | 5 | 2,760 | $221/yr | $773/yr |
| Rivian R1S | 8 | 4,200 | $336/yr | $1,176/yr |
| Kia EV6 | 6 | 3,360 | $269/yr | $941/yr |
| VW ID.4 | 7 | 3,600 | $288/yr | $1,008/yr |
| BMW iX xDrive50 | 7 | 3,600 | $288/yr | $1,008/yr |
TOU off-peak vs standard rate: On Eversource TOU, a Tesla Model Y costs $259/year to charge off-peak. On the standard rate it costs $907/year -- a $648/year difference. For most MA homeowners, enrolling in TOU and scheduling overnight charging is the single biggest EV cost reduction available, even before adding solar.
Massachusetts offers two programs that make the solar + EV + battery combination uniquely profitable compared to any other state.
Additional panels added for EV charging qualify for SMART 3.0 at $0.03/kWh for 20 years, as long as your total system stays at or below 25 kW AC.
If you add a battery to your solar + EV setup, ConnectedSolutions pays you for demand response events. Your battery charges from solar during the day and dispatches during grid peaks.
Note: Unitil does NOT participate in ConnectedSolutions.
| Revenue Source | Annual Value | Notes |
|---|---|---|
| Home electricity offset (6 kW) | $1,700-$2,000 | Avoids $0.28-$0.32/kWh grid power |
| EV fuel savings vs gasoline | $1,556 | vs $3.50/gal, 27 MPG, 12K mi/yr |
| SMART 3.0 (8 kW system) | $240 | $0.03/kWh x 8,000 kWh/yr |
| ConnectedSolutions (Eversource) | $1,850 | 13.5 kWh battery, $275/kW |
| TOU arbitrage savings | $200-$400 | Charge battery off-peak, discharge on-peak |
| Total Annual Value | $5,546-$6,046 | Pre-tax, Eversource territory |
Assumes 8 kW solar system (home + EV), Tesla Powerwall 3 battery, Eversource territory, cash purchase. Propel lease reduces upfront to $0 with monthly payments.
The Section 30C credit was scheduled to run through 2032 but was terminated early by the OBBBA legislation. After June 30, 2026, no federal tax credit exists for EV charger installation. Massachusetts homeowners should install before the deadline.
The residential solar tax credit (Section 25D) expired December 31, 2025. Here is how Massachusetts homeowners can still make solar + EV work financially.
Full system cost with $0 federal ITC. You own the system outright from day one.
Third-party owner claims Section 48/48E commercial ITC. Savings passed to you as lower monthly payments.
The one federal credit MA homeowners can still claim directly. Up to $1,000 for your Level 2 charger.
Adding both solar panels and an EV charger puts significant demand on your electrical panel. Many Massachusetts homes built before 1990 have 100A or 150A panels that may need upgrading.
Most 100A panels cannot support a 40A EV charger plus a 30A solar inverter without exceeding capacity. Budget $2,000-$4,000 for a 200A panel upgrade. Common in older MA homes (pre-1980).
Can work if your existing loads are modest (no electric dryer, no electric water heater). A load calculation by your electrician will determine feasibility. Common in 1980s-2000s MA construction.
A 200A panel can handle solar + EV charging + typical household loads in most cases. You may still need available breaker slots. Standard in newer MA construction.
Smart panels dynamically manage loads, so a 200A panel can support solar, EV, battery, heat pump, and more without upgrading to 400A. Cost: $4,500-$6,000 installed.
MA Permitting Note: Massachusetts requires electrical permits for both solar and EV charger installations. If you bundle the installation, your installer can pull a single permit covering both, saving time and fees. Most MA municipalities process electrical permits within 5-10 business days.
A typical EV driven 12,000 miles per year needs about 3,600 kWh of electricity. In Massachusetts with 4.2 peak sun hours per day, a 440W panel produces roughly 555 kWh per year. That means you need 6-7 additional panels to fully offset EV charging. Efficient EVs like the Tesla Model 3 need only 5, while trucks like the Ford F-150 Lightning need 9-10.
It depends on your utility. Eversource EV TOU off-peak rate is about $0.08/kWh (11 PM-7 AM), making overnight grid charging very cheap at roughly $288/year for a typical EV. Charging midday from solar costs $0 in fuel but requires 6-7 extra panels ($4,000-$5,000). The best strategy is often: solar offsets your home electricity during the day, and you charge your EV at the cheap off-peak rate overnight.
No. The residential solar tax credit (Section 25D) expired on December 31, 2025. Homeowners who buy solar receive $0 in federal tax credits. However, Section 48/48E allows third-party financing companies to claim the commercial ITC and pass savings to homeowners through lower lease or PPA payments. Section 30C still provides up to $1,000 for EV charger installation until June 30, 2026.
Eversource offers a time-of-use rate (R-2) with off-peak pricing around $0.08/kWh from 11 PM to 7 AM on weekdays and all day on weekends. On-peak rates are about $0.38/kWh from 12 PM to 8 PM on weekdays. For EV charging, the off-peak rate makes grid electricity extremely cheap overnight, costing about $288/year for a typical EV driven 12,000 miles.
Yes. ConnectedSolutions pays Eversource customers $275/kW and National Grid customers $225/kW per year for battery participation in summer demand response events. A Tesla Powerwall 3 (13.5 kWh usable) earns roughly $1,350-$1,850 per year. This revenue can offset the battery cost while the battery stores daytime solar for overnight EV charging.
Yes. If your total system size stays at or below 25 kW AC, any additional panels added for EV charging qualify for SMART 3.0 incentives at $0.03/kWh for 20 years. For 7 panels producing about 3,885 kWh per year, that is an extra $116 per year or $2,330 over the SMART term.
In Massachusetts, batteries have an unusually strong economic case. ConnectedSolutions pays $1,350-$1,850 per year. TOU arbitrage (charge at off-peak, discharge at on-peak) saves another $200-$400 per year. A battery also lets you store daytime solar and charge your EV overnight from stored solar rather than the grid. Combined, a 13.5 kWh battery often pays for itself in 5-6 years in MA.
Section 30C provides a 30% tax credit on EV charger purchase and installation costs, up to $1,000 for residential and $100,000 per unit for commercial. It covers the charger hardware, wiring, and installation labor. The credit expires June 30, 2026 under the OBBBA legislation. A typical Level 2 charger installation ($800-$1,200) is largely covered by this credit.
Get a free custom design for solar panels sized to power your home and your EV. We will include Level 2 charger recommendations, Section 30C guidance before the June 30 deadline, and ConnectedSolutions revenue projections.
Section 30C EV charger credit expires June 30, 2026. Act before the deadline.
Complete guide to installing a Level 2 charger in Massachusetts. Permits, costs, and utility requirements.
Read GuideBundle solar panels with an EV charger and get your charger for $0 net cost using Section 30C + Mass Save.
Read GuideCurrent solar panel costs in Massachusetts. State incentives, SMART 3.0, and financing options.
Read GuideOptimize Eversource TOU rates with solar + battery. Stack TOU arbitrage, ConnectedSolutions, and SMART 3.0.
Read Guide