Q: My solar panels have been installed 5 years; would it be financially smart to get a battery when I am on the SREC program? I have 28 panels and have not paid an electric bil since they were installed even with my pool & EV.

A: Great news on your house, pool and EV – you are well ahead of the pack! Arrays that are in the SREC program cannot be later enrolled in SMART. Don’t be too sad though, the SREC subsidy is quite a bit more generous than the SMART subsidy. However, the Connected Solutions subsidy is not dependent on enrolling the array in SMART. The Connected Solutions subsidy is not well documented but, in my opinion, once an incentive is in the electrical tariff it is quite hard to get it out again. Since the Governor just signed a major climate change bill in MA that commits the state to substantial increases in renewable power, I am guessing that the Connected Solutions subsidy will be there for at least 10 years. This was what I assumed when recently I ordered batteries to go with my arrays. One of those batteries is not eligible for the SMART battery adder because the array is enrolled in SREC. The NPV on that battery is about     -$3,000 (the battery purchase price is close to $20,000) but I am doing it because my existing back-up generator is broken beyond repair and buying a new one would cost me about $3,000 plus $500 a year to get it serviced. There is no service cost on the battery.