Quote:
Originally Posted by redpoint5
Quick math double-check...
Where did my math go wrong that I conclude a never payback period, when you figured a 10 year payback?
|
1. You aren't using enough electricity. If you are only using $40 a month you don’t have an all electric house. If you have your own powerplant on your roof you would want to use it.
2. I pay more than 8 cents per kWh – more like 11 cents per kWh after generation, transmission, and distribution charges.
The numbers from my quote (I got 3 they were all very close)
4.97 kWh system
Cost of system: $9489.73 (Using Oregon manufactured panels - cheaper with Chinese panels)
Yearly Production: 5769 kWh (That is 13.25% of nameplate)
Annual Usage: 5840 kWh
My annual bill: $1020
Say I save $1000 a year that is a simple payback of 9.5 years. That doesn’t take into account opportunity cost for investing that money but it also doesn’t take into account electrical rate hikes over the next 30 years the system is warrantied. Add in my $10 per month usage charge and I save $900 a year for a 10.5 year payback.