Could Tesla threaten the grid?

Could Tesla threaten the grid?

Well, maybe:

A house in San Francisco might only draw two kilowatts of power at times of peak demand, according to Pacific Gas & Electric. In comparison, a new electric vehicle on a dedicated circuit could draw 6.6 kilowatts—and up to 20 kilowatts in the case of an optional home fast charger for a Tesla Model S.

jonlivesay | August 19, 2013

Non-issue if we all charge after midnight when demand is low and supply is high.

mclary | August 19, 2013


jq5073 | August 19, 2013

@jonlivesay - True. In fact, spreading demand through the night is actually good for the grid.

Epley | August 19, 2013

There are companies out there, like Calico Energy ( that have software to mitigate the "rolling brownouts" the rumor mongers think will happen if we all go electric.

TikiMan | August 19, 2013

Not with the rate of Solar Power Systems going in on an annual bases. In South Orange County, this year there was enough home solar systems to offset the closing of San Onofre Nuclear Plant.

DonS | August 19, 2013

It's just natural progress. The first homes to be electrified had a single circuit with exposed wires. Homes in the 1950s would get a 6 or 8 circuit panel with screw-in fuses. Homes today have panels with 24 to 42 circuits and a main breaker up to 225A. EVs are just one more modern appliance to go along with central A/C, electric dryers, electric cook-tops, and electric ovens. The only concern is to make sure the power companies are paying attention.

CalabasasKid | August 19, 2013

225A??? My house has a 400A panel

TikiMan | August 19, 2013

I have a feeling with more EV's coming to the market, more home solar-systems will follow. It's a natural progression.

carlk | August 19, 2013

No. The new EV rate of PG&E, for example, will make most EV charging happen at non-peak hours.

Dramsey | August 19, 2013

Not with the rate of Solar Power Systems going in on an annual bases. In South Orange County, this year there was enough home solar systems to offset the closing of San Onofre Nuclear Plant.

Yeah, but residential solar won't do you much good at night. You know, when most people will be charging their cars.

I suspect in a few years we'll have the car<->power company communications the article mentions as a possibility. I'm not worried about the local power company having any control whatsoever over my car...

soma | August 19, 2013

EVs could threaten the grid -- the key is for price signals and behavioral incentives to help it not do so.

In the ideal / fantastical world, EVs could actually help stabilize the grid by providing power back to it! But that's quite a ways off, and unlikely for customers to give control of their precious (and expensive) batteries at the present state of technology.

ppape | August 19, 2013

With our solar panels, we produce more during the day (especially summer)than we consume in a 24 hr period. That excess goes back to the grid and will offset the power we need at night. Those numbers will change during the winter, but overall our use of originated grid power is minimal. I would LOVE to store our own excess power produced, but that's not the way the monopolistic energy companies work.....ugh..... Don't get me started. I just keep repeating to myself....."The Tesla runs on sunshine".....and that makes me happy!


sia | August 19, 2013

+1 @ppape

Same here: Driving on Sunshine!

Solar is a win-win. We are using the Grid as battery. And it helps the power company balance its customer load.

stevenmaifert | August 19, 2013

Maybe if every EV in the country plugged in at the same time, but otherwise... No.

nickjhowe | August 19, 2013

Only 2kW?

Admittedly I'm in Florida and so use A/C a lot, but I typically use $250-$350 of electricity a month; so far this year the car has used $150. So about 7% of my bill.

Dramsey | August 19, 2013

I would LOVE to store our own excess power produced, but that's not the way the monopolistic energy companies work...

Wait, what? How are the "monopolistic energy companies" preventing your from storing your own excess power produced?

Docrob | August 19, 2013

Where I live it is illegal to disconnect fully from the grid in a urban residential property, $10,000 fine. You can have storage but it must remain grid connected, you can avoid buying any power but you must remain connected and pay the daily service fee. AS Solar surges here in Australia one of the solutions to slumping revenues amongst utilities is jacking up daily service charges which are unavoidable.

tes-s | August 19, 2013

Only if PG&E and the regulators allow it.

They simply have to charge more for power during peak periods, less during off peak, and give a break for having "interruptable" circuits that can be turned off by the utility when necessary.

If the electric utilities and the regulators act responsibly, electric cars will be a grid solution, not a problem.

ColoradoBlueS | August 19, 2013

Not worried about the grid as a whole due to mostly off-peak charging, But depending on where you live and how many neighbors happen to install a HPWC off the same neighborhood transformer there could potentially be some unexpected surprises. While preparing for our home HPWC installation I found out that our neighborhood transformer was rated at 25 kva and running close to maximum capcity during peak cooling season. But thankfully my power company has thus far been willing to beef up the infrastructure to make sure the lights stay on for me and my neighbors. I have to give them credit for listening to my questions and actually doing the research to make sure I was not partly responsible for a "Griswold" (Christmas Vacation) moment.

Brian H | August 19, 2013

The utilities will be grateful for the increased nighttime demand.

rbergquist | August 19, 2013

Achilles heel of grids for EV is typically the local transformers. They are not sized for heavy peak loads. PGE did a study to find out where original Prius sales were in order to predict where EVs would reside (seems a reasonable method to locate early adapters). They found initial sales were clustered in older affluent neighborhoods. (clustering in my mind is probably due to income levels, Eco concerns & positive referrals). They then looked at the infrastructure in these neighborhoods and found it to be old and lacking spare capacity. Basically demand had gone up over time but infrastructure wasn't upgraded. So if you sell a lot ofTeslas into these neighborhoods it can cause local failures They haven't budgeted for this capital expense.

Part of reason for EV rate is for power companies to get notified of demand in advance and do engineering calcs to make sure infrastructure is sized properly.

Solar doesn't help this because transformers have to handle hi peaks midday to feed power back to grid and then handle high peaks of demand at night for charging EV.

I suspect rate structures will have to get revisited. If you have solar and it is offsetting your overall demand, power company is receiving less revenue but needs to support higher cost infrastructure. My expectation is for power companies to change to "distribution" companies that get paid for shipping power both ways. I.e. you'll be paying for using them as a giant battery

Mark E | August 20, 2013

What house draws only 2kW at peak? That is a crock. A toaster is 1.5kW, a microwave 1kW and an electric oven 3kW. Cooking dinner with an electric cooktop and the oven going while boiling the kettle.... much more than 2kW.

Here in Australia we use 230V as our normal mains voltage. If you install an inductive cooktop here then its a 32A circuit - 7kW, just for it.

Nexxus | August 20, 2013

+1 Brian H

Utilities are more efficient when running at full power. The full peak power during the day will come in line with more power usage during off hours, allowing the power companies to maintain an even balance 24/7 as time goes by.

Alex K | August 20, 2013

@Mark E | AUGUST 20, 2013: What house draws only 2kW at peak? That is a crock.

I agree. Although not typical, my house draws an average of 5kW (about 4000kWh/mo average and double that during the peak summer season). I'm having a 32kW solar system installed this week which should cover my electric usage.

byoung71 | August 20, 2013

Not according to both the Electric Power Research Institute (the utility industry's research arm) and the Natural Resources Defense Council:

Longhorn92 | August 20, 2013

What ever happened to this line of thinking (

If true, there really shouldn't be much threat to the grid.