Net metering is the quiet workhorse of solar economics in Massachusetts, bigger than the SMART payment for most homes, and almost nobody explains it clearly. Here is the plain version.
What it is
When your panels make more electricity than your home uses, the extra flows back to the grid and your meter banks a credit. When you pull from the grid at night, you spend those credits first. For residential systems up to 25 kW, the credit is at the full retail rate, the same ~$0.34/kWh (supply + delivery) you would have paid to buy it.
How banking works
You do not have to use the credits the same month you earn them. Summer surplus rolls forward and offsets winter bills, when production is low and heating loads are high. Over a year, a well-sized system can zero out the energy portion of your bill, leaving only the ~$8/month customer charge.
How it stacks with SMART
Net metering offsets what you would have paid; SMART 3.0 pays you ~$0.03/kWh on top for what you produce, for 20 years. They are separate and additive. For a typical 10 kW MA home, net metering is worth far more annually, but both matter.
What could change
The Department of Public Utilities is reviewing net-metering credit values (docket D.P.U. 25-200). Future installs could see reduced credits; systems already interconnected are generally grandfathered under existing terms. This is the main reason we tell homeowners on the fence that waiting carries real risk, the rules have only moved one direction lately. We will model your project under current rules and flag the risk honestly.