Massachusetts solar calculator

Live production from NLR (formerly NREL) PVWatts V8. Massachusetts combines full 1:1 retail net metering with the highest retail electricity rates in our verified set (~30¢/kWh on Eversource) — self-consumption value is unusually high. Plus a 15% / $1,000 state income tax credit, a 6.25% state sales tax exemption, and a 20-year property tax exemption (M.G.L. c. 59, §5). The SMART program runs alongside net metering and can shorten payback further — but because its formula and term are disputed, we do NOT model it. This calculator models the Eversource case. Defaults: south-facing roof mount, 20° tilt, 14% losses.