I like a good meme as much as other people, but I get annoyed when they warp things so much that it becomes a lie. This is one such example:


The average home power consumption number is close enough. The Tesla super charger is actually only 250 KW, but I would give the meme creator a pass if they had left that as the worst error.

The house power consumption number is the average, 24 x 7 consumption which means the house uses about 200 KW-hours of energy per week. The charger number is for only for the charging time. Which is probably going to be something like 15 minutes. You have to compare the average consumption over a week to get a fair comparison.

A Tesla Model 3 Long Range car has a 75 KW-hour battery. On the average one would probably charge it from something like 20% –> 80% once or week or less unless you were on a road trip or have a long work commute. That is 45 KW-hours once per week or an average of about 23% of the house energy consumption. That is a relatively large increase in your average electrical consumption, but it is not 260+ houses worth.

The meme was via Happy Little Memes – According To Hoyt.


4 thoughts on “Wrong

  1. Base load is easy to manage and supply. It’s the surge capacity that’s a bear. Most people commuting plug their cars in around the same time, creating larger spikes. Multiply that by many thousands of Teslas and other EVs every night, when people are also starting to cook dinner, etc…… A non-trivial problem.

  2. It isn’t one EV that is the problem, it is when a majority of your fleet are EVs that scale issues come in. I used reference sources for # of cars in Orange County CA (2,299,249 per the CA DMV in 2017), average miles per year ((13,476), and average EV mileage (.3 kw-hr/mile). If all the passenger cars in OC were replaced by BEVs and were recharged every night they would need to add 3.5 GW of baseload capacity.

    In the NIMBY land of California under the gentle ministrations of the Air Resources Board they will NEVER be able to build enough nighttime (fossil fueled) generating capacity to electrify the state transportation system.

  3. I took a ~3 hour trip with a buddy in his Tesla, San Jose to the Sacramento area. We had to find a high output charger to top off the car, where we sat for at least a half hour. On the return trip we had to find a charger and sit again for more than an hour. His neighborhood of $2m+ McMansions has more Teslas than any other car, it seems. Almost every house has one parked outside. Can’t tell what is inside their garages, though. They are all 3-4 car garages.
    Here in the South Bay, there is always at least one of them in sight on the road. Normal to see multiples of them in one view.
    He just had a solar system added to the house, with a Tesla Wall battery system included. Twenty year old house he bought new, with a 300A system. Lots of changes to the electrical system to add the solar and batteries. He tried to turn off the refrigerator when it froze up. Couldn’t do it. the original CB was no longer feeding it. That was annoying!

  4. It’s true that supercharging one car is a short duration high load. A steady stream of cars, which is what you’d like to see at charging stations, would be that same load times the average number of chargers occupied. That’s a big number.
    The other issue is that there are two parameters to consider: energy and power. The added energy use from electric cars is modest but not negligible — I once calculated it at around 20% of the total US electricity consumption. As a fraction of home energy consumption it’s more, enough so that grid upgrades are likely needed. But the other issue is power. Superchargers consume several hundred kW while operating, which requires quite a substantial electric service. A medium size charging station probably requires a dedicated high voltage line, while a gas fueling station requires little more than a typical home or two.

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