I don’t know how wise I am, but I will say I have a lot of experience with system operations, from generation to transmission, to sub transmission to distribution, in times of normal operations and extreme adversity.
I do know what exponential means, this is not just about car charging, although it’s impact will be huge going forward, this has to do with this push towards electrification, there are certain states that are not allowing the installation of natural gas appliances, water heaters and comfort heating. This is an exponential increase in demand. The amount of generation to support this increase in load demand is just one piece of the system, the high voltage transmission lines, sub transmission lines, receiving stations, distribution sub stations and distribution lines will all have to be rebuilt to handle this increased load. These systems are already pushed to their limits and cannot be loaded to the extent to support a small portion of this proposed expanded load. Again, if during high load times “grid operators are bracing for big loads” then the system is not capable of dealing with this increased load. California re set it all time peak load for one hour last year at 51,292 MWs, for one hour. The previous record was set in 2005 at 50,205 MWs. If half of ca’s registered vehicles were electric and all plugged in within a three hour period, that load alone is 59,000 MWs, more than double the current system load, and Ca barely made it at 51,292 MWs, and to do that they had been flying flex alerts for days(public appeal for load reduction), and using interruptible load programs as well as all they peaking units, and it was either this last summer or the summer before where rolling blackouts had to be used to balance laid with available generation resources. In addition to the flex alerts was something new added, don’t charge your electric cars, this was for a four day period. FYI electric vehicles make up 1.8% of the fleet in ca.
Then there is the siting issue, these expanded grid systems need room, a lot of room. And everyone is a NIMBY, not in my back yard. Here an example, SCE was trying to build a new transmission line into so cal from a wind farm, there was enormous public aversion to this project even though it was critically necessary. I do not believe this line was ever completed, and there was plenty of room for it, in the east the transmission line corridors are full to capacity, there is really no room in the existing corridors for expansion. So what’s the answer there? Force people to leave their houses to make room for these new facilities?
VTG.
If the power is out.
You’ve seen the ford F-150 add where the guy plugs his truck into his house and the whole house lights up? That is possible, however it requires an auto transfer switch to disconnect the house from the distribution transformer first or that F-150 would try to back feed the distribution ckt, which it will not but for the briefest of moments before the breaker in the truck tripped. Not having an auto transfer switch is also dangerous to utility workers.
If you are just running a cord from the inverter in your ca to a power strip that will work just fine. In your case that’s 1800 watts of power. I don’t know the KWh of your battery but it’s easy math.
As far as expanded storage goes via a “smart” grid and cars being able to support the grid, it sounds good, and I think it would work, but your charger would have to be changed out to converter / inverter. The converter part changed AC voltage to DC voltage to charge your car. But you need an inverter to change your cars DC voltage back to AC voltage. This is same thing that roof top solar systems work. One thing that needs to be considered here are the losses in the form of heat from conversion / inversion process, probably around 7%, each way I think. It also sounds good until you get into your car and there isn’t a sufficient charge in your cars battery to do what you want.
Here is another thing about home chargers, they all need to be permitted through the utility just as an air conditioner is for load calculations on the distribution ckt you are on. Otherwise you end up with voltage problems on distributions ckts, I’ve seen and dealt with that a lot, people installing loads and drawing permits, mainly extreme low voltage problems. Further, as home car chargers expand, the utility will have to have control of a dedicated meter, smart meter as they are sometimes called that can be turned on or off to control charging, this is already in place in Britain. The reason for this is a phased load increase, as an example if a lot of people get home and plug in within say 30 mins, this could easily exceed the generators ability to respond to that much load pick up,
@2kwik4u mentions that above, all studies aside a very complicated system will have to be in place that allows the utility to phase in car chargers whether it’s peak or off peak load to keep the system Hz in balance. You have to be able to forecast normal load pick up and cold load pick up after an outage to be have resources available to handle this load as well as setting the protective relays properly.
Battery life; These NMC or LFP batteries have a mean cycle life of 3500 cycles, longer if the
DOD (depth of discharge) is limited to 80% or less. A cycle as I understand it is every time a charge is put on the battery. If an electric cars battery is used to support the grid on a daily basis then number of battery cycles is doubled and the useful life of the battery is cut in half. How much is the utility going to pay you for using your battery? Will it be enough to cover half of the replacement cost of the battery?
Another lesser talked about phenomenon that battery chargers induce is the third harmonic. This is caused by the way battery chargers operate to convert the AC sine wave to DC, the charger chops off the upper section of each sine wave to get a clean noise free signal if you will. This in turn wrecks the sine wave and causes excessive heating in the distribution xfmr, and it’s capacity or KVA has to be reduced by 75% if all the load was 100% battery charger load, it’s the same with load that is all computers as their power supplies work the same way. This will require upsizing of distribution xmfrs which increases costs and hysteresis losses in the system that has to be accounted for and will be paid for by the rate payers.
Depending on the load type in a given system, and or distribution ckt, will have something to do with how well car chargers / inverters could support the load in the grid. If the load needing to be supported is inductive, meaning AC / heat pumps or other electric motors then that load is VAR (volt amp reactance) dependent, this is the vertical leg of the power triangle, if just watts / voltage are supplied to a ckt without VAR support this will have adverse effects to the PF in the AC system, this led to a collapse of the 66Kv sub transmission system in the Palmdale / Lancaster area of So Cal where there is a lot of wind generation. Think of VARS as wattless energy, or another way to look at it, if you pour a mug of root beer ? the foam on top of the root beer are the VARS, and the liquid root beer is the watts, the height of the root beer on the power triangle determines angle of the hypotenuse which is MVA or what is called apparent power. While there doesn’t seem to be a lot to the foam, it’s still part of the mug of root beer, and VARS have to be supported. At the distribution level this can be accomplished with shunt capacitors, at the generation level VARS are generated by the level of excitation of the rotor or flux density. In a generator this causes more drag and more power from the prime mover which means more fuel. All that to say, your car charger being used to support the grid has to have away to produce VARS.
I work with a few of them here at Siemens on the Healthcare side. My cousin is a retired Nuc MM. They offered me Nuc school, but I was more concerned with blowing things up, so I was an FC instead. Anyways, definitely a smart bunch! Always great working along side them.
