Utilities Scramble to Meet Power Needs of Electric Cars

[Rhodomel]

Based on the survey of EV's getting mainstream appeal, the utilities are smart enough to scramble to meet expected demands. Here's a nice article why just a few 220 Volt outlet within the city block could become a very big headache even if you recharge at night. Nonetheless, they are dealing with this issue before it becomes too big to handle.


http://www.time.com/time/business/article/0,8599,1910444,00.html

[speculawyer]

But notice it is a transmission problem, not a power generation problem. As too many people bring up without knowing the facts. The existing power generation can handle the cars.
http://www.ferc.gov/about/com-mem/wellinghoff/5-24-07-technical-analy-wellinghoff.pdf

But updating local transformers shouldn't be all that hard for the power companies. Especially if they get the needed supplies early and carefully monitor the system to determine where upgrades are needed.

And where did they come up with this?
At current rates, the electric-fuel usage for e-cars is estimated to be 50% cheaper than gasoline, or about 4 cents a mile.
Isn't more like 1/5 the cost of gasoline?

[paddler13]

Not only that but this statement in the article "Plug-in vehicles draw the equivalent of another house; the system can handle one per circuit, but two or three chargers on the same circuit could cause problems," simply makes no sense. Another 220 volt circuit in a home, as long as it is within the limit of the meter, is really not that big a deal. It is an air conditioner, or another stove, or the addition of an on-demand hot water heater. A single 220volt circuit would have to be a minimum of 200 amps and draw half that continuously to be the equal of another house on the system.

The article reads like FUD to me.

[Rhodomel]

Well, the Times author is more credible than a lot of us here. To declare that the Times article is FUD would imply incredible lack of any understanging on how the city block circuits were currently designed at their assumed capacities.

If you can't understand why a 15 minute/day shutting off of the AC scheduled in coordination with others in a smart grid system during the peak times will tremendously help preventing brownouts, then you can dismiss this article as a FUD for lack of understanding.

Rather than the lazy job of concluding this as FUD, think of why and how it would be possible for a couple of the 220 V 60 A recharging during the peak times could wreck havoc on the originally designed circuit blocks. The current load at peak times can already strain the existing circuits, and the EV recharging was not accounted for in the original designs. The introduction and hopefully mass adoption of EV's will influence on how the circuits should be upgraded or how the new ones will be redesigned and installed. The utilities are smart to scramble for this. I laud them for it. Learning is fun.

[speculawyer]

never mind.

[DonC]

Not only that but this statement in the article "Plug-in vehicles draw the equivalent of another house; the system can handle one per circuit, but two or three chargers on the same circuit could cause problems," simply makes no sense. Another 220 volt circuit in a home, as long as it is within the limit of the meter, is really not that big a deal. It is an air conditioner, or another stove, or the addition of an on-demand hot water heater. A single 220volt circuit would have to be a minimum of 200 amps and draw half that continuously to be the equal of another house on the system.

The article reads like FUD to me.

Well, the Times author is more credible than a lot of us here. To declare that the Times article is FUD would imply incredible lack of any understanging on how the city block circuits were currently designed at their assumed capacities.

If you can't understand why a 15 minute/day shutting off of the AC scheduled in coordination with others in a smart grid system during the peak times will tremendously help preventing brownouts, then you can dismiss this article as a FUD for lack of understanding.

Rather than the lazy job of concluding this as FUD, think of why and how it would be possible for a couple of the 220 V 60 A recharging during the peak times could wreck havoc on the originally designed circuit blocks. The current load at peak times can already strain the existing circuits, and the EV recharging was not accounted for in the original designs. The introduction and hopefully mass adoption of EV's will influence on how the circuits should be upgraded or how the new ones will be redesigned and installed. The utilities are smart to scramble for this. I laud them for it. Learning is fun.
I think what the article is referring to is the fact that since the step down transformers only carry 120V, in many neighborhoods they only service a few homes at an estimated power draw. If houses start drawing more power than anticipated the transformers blow and have to be upgraded. It happens all the time along the coast as more people add air conditioning.

This may well prove to be a problem in some areas but it's not very hard to remedy.

[paddler13]

What homes in this country are fed by 120v? I don't know of many since the line losses would be pretty high, even in a small distribution area. Wherever I've lived transformers have been for each property, not each neighborhood, and the feed has always been 220v, sometimes at 125amp service sometimes at 200amp service (split phase). That's pretty much the standard for US power supply and it goes up from there in terms of what you can get as long as the area power supply can handle it, like extra power for shops, or welders, or businesses or 3-phase power.

The idea that the US power grid cannot handle an additional single 220v 60amp circuit is ridiculous. The home's power capacity would be exceeded long before the grid would if the home is already maxed out on electricity usage.

The article makes no sense and I no sooner trust a journalist on tech issues than I trust a barber for surgery.

[evmavin]

What homes in this country are fed by 120v? I don't know of many since the line losses would be pretty high, even in a small distribution area. Wherever I've lived transformers have been for each property, not each neighborhood, and the feed has always been 220v, sometimes at 125amp service sometimes at 200amp service (split phase). That's pretty much the standard for US power supply and it goes up from there in terms of what you can get as long as the area power supply can handle it, like extra power for shops, or welders, or businesses or 3-phase power.

The idea that the US power grid cannot handle an additional single 220v 60amp circuit is ridiculous. The home's power capacity would be exceeded long before the grid would if the home is already maxed out on electricity usage.

The article makes no sense and I no sooner trust a journalist on tech issues than I trust a barber for surgery.

Where in the US are there transformers for each property? In CA, multiple residences share a single transformer and the houses are fed two legs of 120V and a neutral, combining the two 120 legs gives you 240. There are at least 20 plus homes on the transformer in my area. If multiple homes were drawing 60A on the 240 legs it would be quite a draw if it happened simultaneously.

[DonC]

What homes in this country are fed by 120v? I don't know of many since the line losses would be pretty high, even in a small distribution area. Wherever I've lived transformers have been for each property, not each neighborhood, and the feed has always been 220v, sometimes at 125amp service sometimes at 200amp service (split phase). That's pretty much the standard for US power supply and it goes up from there in terms of what you can get as long as the area power supply can handle it, like extra power for shops, or welders, or businesses or 3-phase power.

The idea that the US power grid cannot handle an additional single 220v 60amp circuit is ridiculous. The home's power capacity would be exceeded long before the grid would if the home is already maxed out on electricity usage.

The article makes no sense and I no sooner trust a journalist on tech issues than I trust a barber for surgery.
It's not that the transformer handles 120V. It's that the standard house current is 120V with maybe one or two exceptions. The lower voltage makes it more efficient to have many small transformers serving a relatively small number of house rather than, as in Europe where the normal current is 220, a much smaller number of larger transformers serving a relatively large number of homes.

I just put "neighborhood transformer" into the search engine. The first result was exactly what I was talking about -- an overloaded neighborhood transformer. If you want to look you can probably find a lot more stories like this. This is hardly surprising. It happens ALL the time along the coast in SD County in neighborhoods which were developed in the last twenty or thirty years. And these neighborhoods have underground rather than overhead utility lines.

http://www.gazette.net/stories/090507/takonew194833_32363.shtml

[Rhodomel]

Agree with DonC and others who have experienced with these issues of local brownouts. With the occurence of more heat waves along the coastal areas, the neighborhood circuits need to be upgraded.

When you originally designed for optimum cost at the assumed power consumption, and the assumptions actually changed in the future, you need to upgrade the design. It is the same with the upcoming recharging of EV's. The existing designs did not consider their adoption, and now is the right time to do the corrective actions before the problems keeps blowing up a little here and a little there, and it should be no big deal to correct them now than later.

[speculawyer]

, in many neighborhoods they only service a few homes at an estimated power draw. If houses start drawing more power than anticipated the transformers blow and have to be upgraded. It happens all the time along the coast as more people add air conditioning.

This may well prove to be a problem in some areas but it's not very hard to remedy.
Exactly. But I wonder how they can monitor this problem and deal with it? Are there sensors in the neighborhood transformers that report how much they are being used? Or do the transformers just blow, causing a local outage that mandates a new transformer . . . and how do they know if it was over-stressed instead of just old?

Perhaps they monitor local building permits and when they see new 220V circuits being added to a neighborhood they consider upgrading the transformer?


BTW, I can see this as an issue but just monitoring the building permits may be enough to deal with it. A lot of older houses only have 100amp service so if they are forced to upgrade to 200amp in order to add a beefy 220V line (such as the 70 amp ones for Teslas) service the utility will definitely be involved.


Thinking about it, a lot of homes really are not ready for a long-distance EV even if cheap batteries were available. PHEVs, EREVs, and small efficient BEVs (Aptera & ~100 mile range EVs) are the way to go.

[DonC]

Exactly. But I wonder how they can monitor this problem and deal with it? Are there sensors in the neighborhood transformers that report how much they are being used? Or do the transformers just blow, causing a local outage that mandates a new transformer . . . and how do they know if it was over-stressed instead of just old?
In my experience the whole situation is handled in a very professional and scientific manner. It's a very hot day and then, blammo, all the power is out. But it's not out across the street. You and the neighbors call the power company. Out comes a truck and the power comes back on. The next day is probably hotter, and blammo, a repeat. This time they come out and tell you they need to upgrade the transformer. This usually takes them a day or two, during which time you hang out in the pool and sleep at your neighbor's house across the road which isn't affected.

Seriously, I think the power companies just wait for the second blow up before they replace anything.

[paddler13]

I've not seen any but the oldest homes and neighborhoods limited to 120v. Standard installation is a 220v 3-phase line to the house that splits into two "legs" of 120v each.

I've never lived in the kind of density that puts multiple homes on one transformer though my present situation is a multi-family dwelling on a street of such and each property has its own transformer.

Brownouts here happen often as well but generally because of some really big demand elsewhere in the system, far more than a few 60 amp 220v circuits or the failure of a transformer somewhere down the line that hiccups the power.

I can sure see plenty of instances where a 100 amp service panel would have to be upgraded to handle an additional load, that's fairly common.