So I just got the "True-Up" for my first year of solar on my home. The net total cost of electricity service for 2018: $140. The costs for 2015-17 were $3660, $3304 and $3688.
True-up is the annual summing up of your NEM charges (Net Energy Metering). These can be credits or debits.
Each month PG&E calculates your NEM charges which are based on electricity usage (grid imports) and excess generation which is exported to the grid. NEM charges are billed or credited based on baseline allowance and time-of-use rates for both import or export and adjusted seasonally. Monthly NEM charges also include fees called "non-bypassable charges" (NBCs) where you pay a tariff no matter which direction the electricity is going. (NBCs are where most of the transport fees for using PG&E's grid live.) There are some other fees added into the NEM charges.
But you don't pay NEM charges/credits until your annual True-Up. (Each month you do have to pay a $10 minimum charge. But that usually gets refunded.)
If at True-Up you end up with a credit PG&E will pay you somehow, but it's not much ($0.02-0.04/kWh).
To make matters even more complicated, but in a good way, in our county we have a community choice energy provider - Sonoma Clean Power (SCP). So we buy and sell our electricity from and to SCP at their rates (which are better than PG&E's). PG&E gives a partial credit off the PG&E rates for power bought from SCP and bills on behalf of SCP. Under NEM SCP runs credits and debits month-to-month, and they actually pay a penny more for generation than use.
If you end up with a net credit of more than $100 in the spring, SCP will send you a check.
So the $140 net total cost I mentioned was my PG&E True-Up charges of $242 minus my $102 credit with SCP. There are no other costs.
The system generated 14.9 MWh in 2018.
Our solar system cost $31K. We got a 30% federal tax credit. So the net cost of the system was $21,700. Based on a savings of $3600/year (which was my average annual cost of electricity before solar) the system will pay for itself in 6 years (ignoring time-value-of-money and changes in the cost of electricity etc.).
