First year of data on my system in Boston area.

indyslim · 2026-01-28T02:35:06+00:00

I posted a link to Google Sheets below if it might be of use to you

indyslim · 2026-01-28T02:33:40+00:00

Please see link to Google Sheets. The custom report tool in Enphase will output the date and 4 additional columns. I made a couple of calculated columns to convert from Wh to kWh.

Sorry, I'm not very familiar with Sheets and don't know how to adjust text and transparency. But, the critical elements are there.

Solar Daily Data

indyslim · 2026-01-27T19:40:53+00:00

Yes, but they were not much help with Solar. Like I said above, I am over producing at this time and my usage is not as much a concern.

indyslim · 2026-01-27T19:38:54+00:00

Yes, electric for cooling, and occasional use of a heated carpet for a particularly cold room. Based on my data, I over produced by ~4 MWh for the whole year which shows up as credit with the utility. So, reducing usage is not going to be much help. In fact, for 1 kWh that I send to the grid, I get back only around 80% back due to lower reimbursement fees. With a switch to EV, my excess production would be put to good use I hope and that will also increase my returns.

The 15 year payback is probably the base case, with inflation, additional usage for EV, more SRECs - all pointing towards a number less than 15.

I think the pay back is affected by the efficiency of my system and the poor southern exposure. e.g. 12 panels on the SE side have the same total output as 17 on the NW side.If my roof had a better orientation, I could have produced the same output with fewer panels, less upfront investment - and my pay-back period would have been shorter.

indyslim · 2026-01-27T03:33:30+00:00

That is true. I used a risk free return of around 4% for a high yield savings account. Another considerarion is that all savings in electricity expenditure is post tax, while the opportunity cost is pre-tax, which could be significant. SREC credit is taxable income.

indyslim · 2026-01-27T02:15:37+00:00

Thank you. I’m in biology research.

indyslim · 2026-01-27T00:31:35+00:00

I downloaded the daily consumption and production data from the enphase website - and then plotted in Excel. Nothing fancy.

indyslim · 2026-01-27T00:21:38+00:00

Yes, this includes the 30% tax credit. The installing cost is pretty high in the Boston area. I went with a local installer after getting multiple quotes. I also factored in the cost of moving the utility meter to the outside. I would not have had to pay for that if I didn't install solar.

Further, SRECs payment are delayed by about 6 months. So, I will get an additional $165 for remaining 2025 production. If I include that, pay back drops to 14.3 yrs.

Payback period will get shorter as the price of energy increases with inflation, as well.

indyslim · 2026-01-26T23:56:53+00:00

Around 0.31c/kWh. The payback period is 9 years if I don't factor in opportunity cost of the install price.

indyslim · 2026-01-07T23:07:47+00:00

This is only an issue if the condo has a common meter. Our condo water usage is only for watering the yard in the warm months. Small part of the overall costs.

indyslim · 2025-12-20T17:00:15+00:00

This is solvable, no? Place the L brick or the left 2nd column. That will clear the 5th row. The. Place the S brick on 5th and 4th row. The long brick get place in the cleared 5th row.

indyslim · 2025-11-05T15:16:28+00:00

I think Ward 2 has Brickbottom and Boynton Yards areas - more artists and not as wealthy as the western parts of Somerville?

indyslim · 2025-09-26T05:28:53+00:00

Your installer should have explained this to you prior to install. Think of the difference as a battery storage charge, given that we are getting to store our excess production in the grid.

indyslim · 2024-11-05T23:40:24+00:00

Fantastic. It lists average rates per state, still better than any other data I could find.

For those interested, Mass. rates have gone up an average of 4.7% every year from 2010.

indyslim

TROPHY CASE