Way too small a sample. As I wrote here:I'm at 0.14/kWh and when taking into account the likelihood that utility rates are almost certain to increase at astronomical levels I think a solar system is a no-brainer (even in the PNW)I agree that if your electricity prices are $0.10-0.13 per kwhr the benefit may just not be there. My own view is one should seek at a minimum a 10 year payback or about 7% nominal IRR?* If doing this using Net Present Value and real cash flows (which makes forecasting a lot easier, to my mind) then I would suggest a discount rate of 3% real would be reasonable (ie 10 year TIPS yield + some illiquidity premium, say 1% pa).
If it's more than a 10 year payback I am not sure it's worth the risk. Depends on the system and location, I guess.
* I've posted quite a few times about ways to estimate Terminal Value or the system depreciation rate (rules of thumb).Code:
Rate increase 2023: 21%.Rate increase 2024: 11%Proposed 2025 increase: 22%
viewtopic.php?t=439793
3) All the solar vendors make it seem like electricity costs just go up steadily year-by-year. The truth is that they can be flat for many years or even go down in costs.
Since 1998 I've maintained a worksheet in which I put in every single line from my electric bills.
To illustrate what I wrote above here is the average cost per kWh in cents on a variable cost basis for certain years: (Note: I live in Western Massachusetts).
1998: 9.4
2004: 9.8
2008: 16.4
2010: 13.9
2015: 20.7
2020: 21.4
2022: 27.9
2023: 33.1
Currently I am at 31.6 cents per kWh
Statistics: Posted by yankees60 — Thu Sep 26, 2024 6:31 pm — Replies 153 — Views 8638
