Q: battery disposal;a big problem?

A: This is very unlikely. Batteries contain a lot of valuable metals like lithium that is expensive to mine. Hence, just like aluminum cans, batteries will get recycled. However, the infrastructure to recycle batteries is not yet widespread.

Q: Can the battery back up really run the heat pumps and for how long?

A: A 10kWh battery can only power a heat pump for an hour or less. The better way to add a battery is to keep your fossil-fuel furnace and have the battery run only the emergency circuits on your house like the fridge, lights, burner circuit, circulating fans, water pump and a few outlets. Together these might draw about 10 amps, 1kW or about 1 kWh per hour so a 10kWh battery would last you 10 hours.

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.

Q. My house has solar, but because the company that installed the panels is now out of business, the monitoring of the solar is inaccessible.

Q: Is there a third party monitoring system that could be added to an existing system so that I can see more than just my net usage, but actually see if my solar panels are producing as I’d expect? Is there a way for people installing solar from the beginning to ensure that monitoring will remain available (open source access)? Is that common in single family homes?

A: Do you know who made your inverter? It is often SolarEdge or EnPhase. The app for your smartphone (and the web portal) comes from them not the installer. I think if you contacted them they could sort it out for you. If that does not work let me know. You will not be the only person in this situation as solar installers go bankrupt quite often.

Q:  Are there solar systems that will provide enough power for our home during a power outage?

A: Yes, but probably not the whole house, probably only the circuits you would power from an emergency generator. Since solar panels must, by law, disconnect from the grid during power outages (to prevent the linemen getting electrocuted by your solar power) you will need to install a re-connect switch at your electrical panel just like that for a back-up generator. This usually needs to be installed with a battery, but when the grid is out and the sun is shining you will be powering the house from the sun. Nice. I intend to do this on my house this year. I have just ordered batteries to be installed at my house to replace our ancient (and no longer working) propane generator.

Q: What if you need to put on a new roof within a few/several years of installing solar.


A: I replaced my 20-year old roof before adding solar panels. Taking the panels off to install a new roof will cost you more money, so if the roof will need replacing within the next few years, I think it is better to do it now. Solar panels will extend the life of the roof because it is the sun that deteriorates the asphalt not the wind and rain, and with solar panels, the asphalt is now shaded.

Q: Have you looked at Tesla solar roofing tiles?

A: I have, and I have concluded that they are just too new to even be considered at this point. A roof is a long-term investment. Until there is some data from roofs other than that on Elon Musk’s house, I will be cautious of these new products. 

There have recently been a few reports from people who have installed the Tesla solar roof. The numbers are not encouraging. The Tesla solar tiles are only about 4-5% efficient compared to solar panels that are about 20-21% efficient. The cost of the installed power is about $4.62 per Watt compared to solar panels at around $2.80-$3.00 per Watt. The Tesla solar roof is about 50% more expensive than solar panels and about one quarter as efficient. I was right to be cautious of this new product.

Q; What if your roof has too many gables and “wrong’ angle for solar panels?

A: Complex roof lines reduce the number of panels you can fit on a roof. Almost all solar installers today use a software package called Aurora that calculates how many panels can fit on a roof using satellite data on the angle, shade and orientation of the roof. I have found it to be very accurate. If your roof cannot fit enough panels to cut your carbon footprint to zero, I suggest looking at community solar options. There are several companies in MA that offer this. They build large solar-panel array in big fields in MA and sell you the net-metering credits at a discount of usually 10% (one offers 12.5%) to the utility price of electricity. These net metering credits appear on your electric bill. This is a very good option if your roof is not suitable for solar panels.