Utility Rates for EVs

[Norbert]

Are you sure about that? Everything I've found indicates that unless you produce more electricity than you use, you get nothing back, and the new net surplus compensation program, only applies to net generation, not net value, leaving a big hole in between.

From the PG&E FAQ:

That seems like mixing two ways of counting which should't be mixed. Not just confusing, but also arbitrary.

 

[Robert.Boston]

Agree, Norbert: wholesale electricity prices in California change minute to minute. PG&E should pay you that real-time value of power when you inject power, and charge you that price when you draw power. (Other charges for infrastructure, etc. would be extra.)

OTOH, "running the meter backwards" means that you avoid paying your pro rata share of the infrastructure costs that allow you to buy and sell power. I'm having a hard time rationalizing that -- the grid isn't any less valuable because you're selling across it, rather than buying from it.

 

[Norbert]

OTOH, "running the meter backwards" means that you avoid paying your pro rata share of the infrastructure costs that allow you to buy and sell power. I'm having a hard time rationalizing that -- the grid isn't any less valuable because you're selling across it, rather than buying from it.

I'd guess that in theory the grid cost would be built into getting a lower price for selling than for buying (at the same time-of-day). That might get more complicated by perhaps subsidies begin built into the selling price as well.

 

[rolosrevenge]

This could be a non-issue if V2G was designed as two-way communication, but only one-way power flow to the vehicle. The car could tell the utility its planned departure time, and how much energy it needs before then. The utility could charge when most convenient for them. If 60 MW of spinning reserves were needed, they could temporarily take 10,000 6kW chargers off-line. This would be just as good as drawing 6kW from 10,000 fully charged vehicles, without impacting battery life.

The whole point of V2G is that it's "Vehicle to Grid". What you're describing is just intelligent charging -- valuable, but only half the pie. If the grid operator has 100,000 V2G EVs plugged in on a hot summer day, each with a 10kW dual-direction interface, it has 1,000 MW of synchronized reserves, the equivalent of a having a backup nuclear station (but instant-on). Currently we pay power plants serious bucks to operate below their maximum normal rating to provide this same spinning reserve service, which is both costly and polluting. And, as an added bonus, this power source is concentrated in urban areas (where we've parked during the workday), so the extra power is readily deliverable to load.

And now you get to one of the fundamental questions of my dissertation. According to Alec Brooks, V2G is the provision of energy and ancillary services from a vehicle to the grid. This is the definition that I have pushed in all of my V2G papers so hopefully it will stick. That means unidirectional V2G (I think I coined that one) is legitimate V2G technology. Using unidirectional V2G you can perform spinning reserves and frequency regulation. The benefits are lower than with bidirectional V2G, but so are the risks. I have a great paper on this that should be on IEEE Xplore early access within a few days if you have access to it you can search and find it.

Now the big problem that Duke faces is that they can't get a price differential high enough to ensure off peak charging. Even if they only charged $0.01/kWh you would still only save a little less than $300 per year on your electric bill. That may motivate some people to schedule their charging but a lot will probably want to plug in as soon as they arrive home and be willing to pay for the convenience. As long as they are charging 6.6 kW or less, it isn't a problem. California and other places will have different dynamics.

 

[Norbert]

Now the big problem that Duke faces is that they can't get a price differential high enough to ensure off peak charging. Even if they only charged $0.01/kWh you would still only save a little less than $300 per year on your electric bill. That may motivate some people to schedule their charging but a lot will probably want to plug in as soon as they arrive home and be willing to pay for the convenience.

No, no, off-peak charging is done automatically via software. You still plug-in as soon as you arrive at home. So there is no loss of convenience, it's a one-time set-up. Who would not do it if it saves $150 per year, $1500 over a 10-year ownership?

But in the absence of off-peak rates, perhaps almost nobody would do it, and that would require:

a) larger transformers than necessary
b) more power plants than necessary
c) more stress on the grid than necessary

All of which, in the end, the customer will have to pay for. Just so that the utility has it "easier" ?

As long as they are charging 6.6 kW or less, it isn't a problem. California and other places will have different dynamics.

If 6.6 kW is not a problem during peak time, then 10 kW should not be a problem during night, I would expect. If really necessary, a during-the-day limit could be achieved with software as well, even pre-set as default by the factory (if really necessary).

 

[Lloyd]

Are you sure about that? Everything I've found indicates that unless you produce more electricity than you use, you get nothing back, and the new net surplus compensation program, only applies to net generation, not net value, leaving a big hole in between.

From the PG&E FAQ:

This was passed by voter referrundum last year. It comes into effect in 2012 at your next true up period I was told earlier this year. It may have changed since that time.

 

[rolosrevenge]

No, no, off-peak charging is done automatically via software.

But if there is any way for the customer to override it, ever, then there has to be a bigger transformer to meet the extra load, and if that extra load is going to be larger than 6.6 kW, then your normal energy purchases will not cover the upgrade cost and so they would want to charge you more. Would you be willing to hand 100% control of your charging over to the utility? If not, you see their dilemma.

 

[Norbert]

But if there is any way for the customer to override it, ever, then there has to be a bigger transformer to meet the extra load, and if that extra load is going to be larger than 6.6 kW, then your normal energy purchases will not cover the upgrade cost and so they would want to charge you more.

Since thinking this way doesn't address all the other problems this strategy causes, it seems a rather construed argument: there are thousands of other ways customers can cause an unexpected above-average demand of 3.3 kW, and the utility will never buy transformers large enough for the theoretical worst-case. You can't solve that by charging extra for anything that could ever, ever have such an effect. That requires a smart-grid (not just smart charging for EVs) in order to be effective, which is one of the reasons the DOE is actually working on that.

It will take years until there are an interesting number of people who would potentially have larger than 6.6 kW chargers. EVs like the Leaf will initially far outnumber those, so a higher fee for 10 kW chargers won't even help noticeably with financing the initially necessary transformer upgrades. That will only start to matter further down the road when the situation will be very different in any case. The only thing it effectively does, is it sends a signal in the wrong direction.

For the reasons given in my last post, it is *much* more important to get EVs to be charged off-peak, all of them, not just the currently rare higher-rate chargers, (which actually *help* in getting the charging to happen at the lowest off-peak time).

Would you be willing to hand 100% control of your charging over to the utility? If not, you see their dilemma.

It seems Duke Energy already tries to control my charging, but in the wrong direction. In a sense, that is already the worst thing that could happen. Utilities need to *support* higher-rate chargers so that charging can happen mostly at the lowest level off-peak period, since *that* is what guarantees the most effective way to use the grid and the existing power plants.

 

[Tommy]

My biggest gripe with EV rates is the requirement to have a second meter installed for the EV to get the EV rate (vs. whole house). The $2k+ cost to install a second meter puts any savings to far out into the future. Only one smart meter should be needed per dwelling and that smart meter should be able to "sense" when a EVSE is in use. Currently, the alternative to a second meter is whole house metering with the smart meter determining the time of electrical use. That's fine for nite time charging, but for us that conserve electricity to begin with, it penalizes us for using our A/C during peak hours. In other words, the fixed tier rate is cheaper for those that conserve than the time of use rate; we are paying a higher rate overall for adding a EV even thou we charge at nite.

 

[rolosrevenge]

That requires a smart-grid (not just smart charging for EVs) in order to be effective, which is one of the reasons the DOE is actually working on that.

But still, a smart grid can only do so much unless the customers cede the necessary control. I am all for it. I am working on a DOE smart grid project and have written numerous articles on the benefits of the smart grid technologies. I can also sympathize with utilities who see it far easier at the onset to simply charge a fee for a certain size charger. The utilities are extremely cautious about new technologies because of reliability reasons. Hopefully smart grid projects like the one I am involved with will convince them that there are better ways. It is very comforting to know that 6.6 kW charging or less won't break the distribution grid even with peak charging and necessary upgrades will be paid for by the EV owners themselves instead of everyone else. That goes a long way to combat a lot of FUD out there on the subject.

 

[Norbert]

But still, a smart grid can only do so much unless the customers cede the necessary control.

Sorry, this, and your discussion of the smart-grid, is ignoring the most crucial fact in this situation: Off-peak rates don't require a full smart-grid or even ceding control, they only require time-of-day metering.

I can also sympathize with utilities who see it far easier at the onset to simply charge a fee for a certain size charger.

I find that difficult. It is a bad way to ensure they make enough money, creating more problems than it solves. Should we assume that they prefer to build more power plants if it allows them to charge higher rates, and they don't mind if existing power plants are used inefficiently and costly? *We* will have to pay for that !

Why do you sympathize? Because it means they will actually allow EVs to charge, instead of telling potential EV owners that they can't charge at all?

It is very comforting to know that 6.6 kW charging or less won't break the distribution grid even with peak charging and necessary upgrades will be paid for by the EV owners themselves instead of everyone else. That goes a long way to combat a lot of FUD out there on the subject.

Which FUD, the assumption that supporting EVs would be impossible? That has already been refuted many times. Several utilities are on record that the grid, with feasible upgrades, will be able to support a full electric fleet. Has Duke Energy been doubting that?

 

[Norbert]

In other words, the fixed tier rate is cheaper for those that conserve than the time of use rate; we are paying a higher rate overall for adding a EV even thou we charge at nite.

Yes, those rate models seem broken. Many get the impression that the utilities do not truly want to pass on the benefits of more cost-efficient off-peak electricity. Or have unexplainable difficulties in doing so.

 

[Dave EV]

My biggest gripe with EV rates is the requirement to have a second meter installed for the EV to get the EV rate (vs. whole house). The $2k+ cost to install a second meter puts any savings to far out into the future. Only one smart meter should be needed per dwelling and that smart meter should be able to "sense" when a EVSE is in use.

How is your "smart meter" going to sense when the EVSE is in use and how much power it's drawing unless you have a dedicated, revenue grade meter sitting on the lines for your EVSE?

I know the Blink EVSE has a meter in it, but it certainly isn't anywhere close to revenue grade in current form. It loses data all the time.

In most cases the cost to install a 2nd meter isn't too bad if it's done the same time that the EVSE is installed - and most critically - the utility doesn't require a separate service drop/tap for the meter. For example, SDG&E lets you install the 2nd EVSE meter off your main service panel and then subtracts EVSE usage recorded on the EVSE meter from the main meter.

 

[Tommy]

How is your "smart meter" going to sense when the EVSE is in use and how much power it's drawing unless you have a dedicated, revenue grade meter sitting on the lines for your EVSE?

I know the Blink EVSE has a meter in it, but it certainly isn't anywhere close to revenue grade in current form. It loses data all the time.

In most cases the cost to install a 2nd meter isn't too bad if it's done the same time that the EVSE is installed - and most critically - the utility doesn't require a separate service drop/tap for the meter. For example, SDG&E lets you install the 2nd EVSE meter off your main service panel and then subtracts EVSE usage recorded on the EVSE meter from the main meter.

If I was designing a smart meter I would make it capable of detecting a pilot signal from the EVSE on the amount of power being drawn; there is no technical reason that cannot be done. Regarding costs for the second meter, a dedicated line from the second meter to the ESVE must be run and that is about a $2k cost. A truly "smart meter" would be able to segregate EVSE use from the rest of the household. There are plenty of devices on the market that communicate with each other via wiring in the home, no reason a smart meter shouldn't be able to as well.

 

[Tommy]

The OP requested our thoughts on what's working and what's not with our own interaction with our utility: rates, metering, etc. I found it disingenuous for SDG&E to not have a "smart meter" that could distinguish between EV charging use and household use. Their solution to install a second meter makes payback almost impossible.

 

[Dave EV]

The OP requested our thoughts on what's working and what's not with our own interaction with our utility: rates, metering, etc. I found it disingenuous for SDG&E to not have a "smart meter" that could distinguish between EV charging use and household use. Their solution to install a second meter makes payback almost impossible.

Let's say the meter costs $2k as you suggest. For most people, the meter with TOU metering will allow them to charge their EV at $0.14 / kWh instead of $0.30 / kWh as the added load from the EV will almost always put the customer into the upper tiers of usage.

Assuming your efficiency is about 300 Wh/mile, the meter will payback in about 50,000 miles. For most people that's around 5 years of driving. Pretty good ROI if you ask me.

I was lucky and didn't have to pay for my 2nd meter (or my EVSE) thanks to the EV Project. But I would have paid it without question.

 

[Norbert]

For example, SDG&E lets you install the 2nd EVSE meter off your main service panel and then subtracts EVSE usage recorded on the EVSE meter from the main meter.

That would sound like a good solution. Such a sub-meter shouldn't cost very much if produced in quantities. Consider all the stuff electronic devices are doing nowadays for little money. Eventually it could even be built into the EVSE (possibly), once utilities can agree on a common protocol.

 

[rolosrevenge]

Sorry, this, and your discussion of the smart-grid, is ignoring the most crucial fact in this situation: Off-peak rates don't require a full smart-grid or even ceding control, they only require time-of-day metering.

Even if you have time of use metering, say there is still a 5% chance that you will need to do some peak charging. If you've got 1 other person on that transformer with a similar probability then you've got about a 90% chance that in a given year you'll both be charging on peak. If that additional load will blow the transformer (13.2 kW), the utility either needs to upgrade the transformer or install some control methods to curtail other load when the coincident charging occurs. It is easier for them to install a larger transformer. The size of that transformer is a function of the maximum rate of charge. Another problem is that there isn't enough data supporting that the majority of the people will charge at night given the option for off peak rates.

Why do you sympathize? Because it means they will actually allow EVs to charge, instead of telling potential EV owners that they can't charge at all?

No I sympathize because that way they don't get angry customers who get blacked out because two of their neighbors bought EVs and blew up the transformer and then have to pay higher utility rates to pay for extra large transformers. Ultimately it is the utilities job to accommodate whatever people plug in. Those costs are spread across the entire rate base. If they don't make enough money doing it, then they go bankrupt. If a few people want extra large chargers in their garages, I see no problem charging them extra or forcing them to never be allowed to charge on peak. 6.6 kW charging, from 6 pm to 6 am gives you 79 kWh. Do you need more in a given night?

Which FUD, the assumption that supporting EVs would be impossible? That has already been refuted many times. Several utilities are on record that the grid, with feasible upgrades, will be able to support a full electric fleet. Has Duke Energy been doubting that?

Duke hasn't doubted that they could support EVs, but the occasional article pops up frequently enough that I felt it was worth mentioning.

 

[Tommy]

Let's say the meter costs $2k as you suggest. For most people, the meter with TOU metering will allow them to charge their EV at $0.14 / kWh instead of $0.30 / kWh as the added load from the EV will almost always put the customer into the upper tiers of usage.

Assuming your efficiency is about 300 Wh/mile, the meter will payback in about 50,000 miles. For most people that's around 5 years of driving. Pretty good ROI if you ask me.

I was lucky and didn't have to pay for my 2nd meter (or my EVSE) thanks to the EV Project. But I would have paid it without question.

I was comparing the whole house EV rate to the separate EV rate that requires an extra meter. The payback is much longer than 5 years. But that isn't the point, why not make a smart meter that can distinguish EVSE use from other electrical use. It avoids the permits, plan checks and the expense of installing a second meter. I see this as just one more obstacle to main stream adoption of EV's.

 

[Norbert]

6.6 kW charging, from 6 pm to 6 am gives you 79 kWh. Do you need more in a given night?

It doesn't really matter how much I need in one night. The problem is that you are telling people to start charging at 6 pm, and that isn't off peak, that's when lots of people come home.

Even if you have time of use metering, [...]

What do you mean with "even if"? That's the main point !

Another problem is that there isn't enough data supporting that the majority of the people will charge at night given the option for off peak rates.

There won't be much data coming soon since the currently offered time-of-use schemes appear to have built-in points of failure.

Nevertheless the crucial point is to have EVs charging off-peak, and until you understand how important this is, and that it does't depend on the things which you think it depends on, you won't be able to make sense of the other arguments I'm coming up with.