How does net metering work ? (PGE, nothern california)

[sparkle]

Surprisingly there is very little information on how billing works for net metering.
I have a basic question, does net metering work on dollars or on KWh.
or in more simple terms, when in day time I am pumping electricity back do they just count it as a KWH which is offset against night KWH or do they credit the cost of electricity in day and charge it back in night.
The difference between these two is important since if they credit the dollars, it would be better for me to switch to EV or E6 plan which has very high rate in day time and buy at low rate in night. Here is example to illustrate..

1) dollar credit -- I switch to E6 or EV plan. One extra KWH produced in daytime will get me 34 cents and at night I buy tha KWH at 19 cents. So I will he ahead by 15 cents.
2) KWH credit -- I keep any plan, any KWH produced will net out any other KWH at same price, so no net advantage.

so how does it work ? and what are gotchas ? will PGE require me to buy special meter for option (1) or there are rules about (1) which reduce my benefit ?

[sensij]

The credit is in dollars. TOU is definitely a nice complement to net metering if you do not have heavy peak period consumption. The only real "gotcha" is that the rate plans are not locked in, so over the next few years as rate reform kicks in you might see some of those changes flow through into TOU plans as well, including monthly minimum or fixed charges.

[inetdog]

There is no charge for any required changes to the meter used. The basic smart meter can do simple net metering. For TOU it requires programming with the rate periods or else the billing computer has to work with all of the 15 minute totals from the meter.

[Willaby]

Surprisingly there is very little information on how billing works for net metering.

I think the lack of information is deliberate by the Utilities. I'd called them and either received bad information or they ask me to call back when their "TOU EV expert" is in. The proof to me was talking to people who were actually on the program with solar and an EV.

I've got SDGE (the worst!) and a Chevy Volt EV. Our TOU EV summer peak is 49c and super off is 17c. The benefits and the ROI of solar+EV are almost too good to be true. I did a spreadsheet on it: my new system will generate estimated 100% of my annual kwh usage, but will generate 30% more $ credits on my bill. Of course they won't cut me a check for that, but my bill should be virtually zero. I could have saved a couple thou and just covered 80% of my kwh usage to zero my bill, but I'd rather plan ahead and also say "screw you!" to SDGE.

SDGE might be somewhat unique in that they must only make a profit on the delivery, but actual cost of the energy must pass through. I think they must pay me 4c for the kwh over generation and if so, this might just cover my gas usage.

[sparkle]

thanks for responses.
now from what I read, there are two factors which will affect the bills..
1) How much I generate in day and how much I use at night. for argument sake, I sell it to them at 35 cents in day and buy it back at 15 cents at night. That leaves me 20 cents profit.
2) if i overproduce, at end of year they pay me wholesale rate of whooping 3 cents/kwh.

so how does calculation work considering above two factors ?
does it work this way ?
assuming I send them 10 kwh in daybut use 8 at night. (oversimplifying to one rate across whole year and just peak/offpeak rate, no daily meter charge etc)
Then theoretically SUM of
a) 35cents(daytime)x8kwh(equal to used at offpeak) -15cents(offpeak)x8kwh(actual offpeak usage) (this can not be less than 0)
b) 3cents X 2kwh(overproduced)

[sensij]

The net metering credit you calculate in (a) can only be applied to electricity use in the relevant period (aka 12 month billing cycle). If you have a running "credit" by calculation (a) at the end of your true-up year, it will not be paid out, the calculation reverts to (b).

The calculation in (b) is what is done at the end of the year to see if you get a check in the mail for excess kWh generated but not consumed.

TOU, done correctly, means that you use more kWh than you generate, so (b) will not apply. If you generate more kWh than you consume, there is no benefit to TOU pricing under current rate schemes.

[J.P.M.]

At this time, in CA, excess generation accumulated at true up will be paid at wholesale rate. As Sensij writes, the overgen. $$ amount shown on your monthly statement is against future use. It's a paper #.

Depending on rate reform, the amount paid for excess generation at trueup may be changing. Stay tuned.

[sparkle]

is there a xcel or formula which makes it little easier to understand the credits part ?
i think i will produce more electricity (in pure kwh terms) on a typical day (assume same for whole year, to keep it simple).. in addition I am switching to E6 rate (with heavy usage shifted to nights). So how would my credit be calculated ?

[sensij]

The PG&E E-6 rate is the most complicated of the TOU plans I've looked at. I've started working on a spreadsheet to calculate it, but haven't focused on it and haven't finished. The details on how to calculate the credits can be found in a post a couple years ago.