Dual Electric Meters

Dual Electric Meters

My electricity provider (Pacific Gas & Electric) has a couple of rate plans for EV owners. One option is to install dual meters so that you can put your home EV charger on a dedicated meter which allows you to not only track your car’s electricity usage, but also includes a rate plan that takes advantage of low cost middle of the night charging. The rest of your house would then be on the second meter and remains on a more conventional rate plan. I was wondering if any of you current EV owners have gone for this option, and if you think it was worth the expense of installing a whole new service panel (probably several thousands of dollars).

hmgolds | 11 september 2017

"Several thousand dollars" seems high to me for installing a 2nd meter and the attendant service panel, but I suppose it's possible.

Some utilities are providing "time of day" metering. Still a single meter and service panel I think. For example:

If installing a separate meter, consider that some utilities have a fixed monthly "service" charge per meter. That may negate some of the benefits.

carlk | 11 september 2017

You must be talking about the EV-B plan. I have the PG&E single meter EV-A plan which I think is great. I have no problem to charge my two Tesla at off-peak hours. You probably will save on your regular usage too if you reached the top tier, which I think we all do, on tiered rate plan.

andy.connor.e | 11 september 2017

How much electricity will you have to save with the fluctuating rates at night, to equivilate spending thousands to install another meter? I dont agree its a good investment. Electricity is already cheaper than gas.

Carl Thompson | 11 september 2017

I looked at that when I put in my EVSE. But when I priced it out it was way too expensive as you say. A few cents savings per kWh is not worth the thousands of dollars price for the panel / meter / installation / inspection.


rxlawdude | 11 september 2017

There is a "submeter pilot program" where a third party provides a Wi-fi connected meter just to the line feeding your EVSE (or NEMA 14-50). All usage data goes to the third party, that then relays it to the utility.

The utility subtracts any consumption for EV charging from your whole-house consumption, and then split bills: the EV charging power at the TOU-EV rate and your home at whichever rate plan you choose.

Unfortunately, the enrollment period for this Phase 2 pilot ended in April. I fully expect that once the pilot programs are completed, this will become a tariffed approach that saves the cost of installing a separate meter at the service entrance.

Haggy | 12 september 2017

I have EV-A and haven't heard of a good reason for anybody to get the separate meter. The TOU plan cuts out the tiered rates and you may be far better off even for your standard energy. I've heard from people whose bills didn't go up after they got a Tesla because the TOU of the EV-A lowered the rate for their other energy needs. If you don't use a lot of peak energy, which is the case for many people who work outside of their home for a living, EV-A might be a good deal overall.

Another thing you can do is apply your federal tax credit money toward solar. It should cover more than the cost of the additional panels you'd need for the car above and beyond what you'd need for the rest of your electricity.

rxlawdude | 12 september 2017

@Haggy, thanks for further clarifying. I meant to mention that the EV-A and EV-TOU rates are not cheaper than TOU-B rates.

There is one situation where it MAY make sense to do the submeter/second meter approach: if you are hellbent on staying on a tiered rate plan. The subtraction of the charging consumption may result in the house staying in the lower tiered rates 24/7.

When Phase I of the submeter program went away last year, we switched to TOU-B and just charge at night. That was after the shock of our bill on the tiered domestic rate. Now, happy clams on TOU-B and our 6kW PV system pretty much covers most of the summer days' A/C during the peak rate periods. 90% of each months' consumption is super-off-peak EV charging.

carlk | 12 september 2017

Haggy The only good reason for having a separate meter is if you have to charge outside the off-peak hours.

cephellow | 12 september 2017

I installed 2 meter 400A panel, upgraded to underground service, all that stuff. Did all the work myself with plans and inspections for about $1600 in materials , inexpensive only because I know what I'm doing. I also got a really good rebate and price break from PG&E because of EVSE install, but I had to point those rules out to the PG&E project planner because he was completely unaware of PG&E's own programs.
The main reason I did it was because I wanted the underground service anyway. PG&E can't be trusted with their rate tier manipulations, and their 2 meter plan was locked-in so I did that.

Mozart | 13 september 2017

I have a 7kw solar panel system (26 panels) and am close to a "break-even" at true-up every year. I live in Northern California and have Net Energy Metering (NEM) with Pacific Gas and Electric Co. I have a Model S and a reservation for a Model 3. Since I'm producing my own electricity, would it be beneficial for me to switch to a time of use plan.

bmz | 13 september 2017

When I first saw the title only, I was sure it was a typo, and you really meant "dual electric motors" :-)

jje | 13 september 2017

This is exactly what I did in 2002 when I bought my Rav4 EV. Worked out very well since we pretty much only charged when the electricity was cheap. But now, that we've installed solar, we've move to one Time of Use service for house and car.

Carl Thompson | 14 september 2017

"Since I'm producing my own electricity, would it be beneficial for me to switch to a time of use plan[?]"

Unfortunately PGE's current time-of-use plans are not as good as previous ones. Currently their "best" plan has their peak hours (highest rates) between 3pm and 8pm. This is less than idea for solar because almost all of your generation is done before the peak time begins. Therefore you'll get lower off-peak rates when you sell your excess solar power pack to PGE.

Up until last year you could switch to the much better E6 time-of-use rate plan (that's what I have). On that plan peak rate time starts at 1pm and "partial peak" rates start at 10am.Therefore almost all of my solar power generation is at times when PGE has to pay me higher rates for my excess power.

It still may be worth going through your own personal numbers and usage and calculating whether the current time-of-use plans will provide some small benefit.


Haggy | 14 september 2017

My peak generation from solar is around noon. By 3pm I'm down to about 2/3 of what I was generating at noon, but it's dropping off rapidly and by about 4:30, everything for the rest of the day combined is about as much as 15 minutes generates at noon. So PGE is paying me partial peak rates for most of my energy and selling much of it back to me at peak rates. That's today and December will be another story.

On the other hand, if you consider just the EV related panels (i.e. I have more panels than I would have had, had I not sized it for an EV) and that those panels generate most of their energy during part peak hours, some of it during peak hours and PGE sells it back to me at off peak rates to charge my car, it means that if the rest of my system is sized correctly, I need about half as many panels added when you compare the amount generated to the amount consumed by charging.

So as far as solar for EV alone, the cost of adding additional panels at the time solar is installed will be far less than the tax incentives on the EV, and will be closer to what I used to spend on Gasoline in under two years.

PGE does get a good deal out of it when they buy things at TOU rates and sell it back to you in general. But for EV charging, it works the other way around.

NumberOne | 15 september 2017

I am on the East Coast, and have a dual meter plan, My bill went up around 10%. The EV portion is all of $23 per month of which only about $3 is actual electricity. The rest is simply fees and taxes. The single meter plan also offers a discount as far as I know, but you have to sign up for an EV plan. Now that I know how little a difference it makes, I would say that in the long run it will not matter whether you have one meter or two. I like to be able to track how much the car uses.