Thought experiment: Electric cars vs. the environment

If you want to pick a fight with me, tell me the climate issues we’re having right now are cyclical. That’s the HOV lane to me insulting you and your future progeny until seventy times seven. I feel strongly about climate change — given the unrelentingly bleak repercussions for everything and everyone forever, I think it’s the most important issue facing the world’s governments today.  Economies ebb and flow, employment rates rise and fall, but breaking the food chain is forever.

Naturally, I try to follow as many suggested solutions as possible, when I’m not distracted by my primary hobby (tire fires) (I am a creature of inconsistency). Which brings me to the electric car.

I understand that Tesla Motors is doing well and is going to start repaying their government loan early. Good to see. But how much can the electric car help? The electricity to charge the battery has to come from somewhere. Right now, it mainly comes from coal; burning coal generates 44% of the U.S. electricity. What will happen if we create more electricity to charge our cars? Will we be polluting ourselves even worse than we are now?

Also, when Jim Inhofe dies, can we put him in an electric hearse for his final drive to a mulch pit?

That's a pretty smile. I know some bacteria that'll love that smile.

That’s a pretty smile. I know some bacteria that’ll love that smile.

Let’s see what we can learn. I’ll trust you guys to check my math/logic.

The Question

Assume we replace every car in the country with a mid-range electric car from Tesla motors. What will that do to our electrical grid and our pollution to power that grid?

Just to make driving even more fun, let's assume we all have the same color too

Just to make driving even more fun, let’s assume we all have the same color too

The Values

Charge per car battery: 60 kWh (their mid-tier battery — they range from 85 to 40 kWh)

Distance per charge:  230 miles (this depends on your driving style — 230 is the range Tesla supplies for city driving at 55mph on a 70-degree (F) day for this model and battery)

Miles driven per year: 3 trillion (it’s actually remained flat for a decade)

Electrical output per year (U.S.): 4,500 TWh (estimated — it was 4,370 in 2008 and we all have iPads now)

I’m including truck miles in with the total miles. The data I have don’t break the number out enough to say how many miles are just normal commuters driving their F-150s to a kid’s soccer game and how many are actually big rigs bringing their horse patties to Wendy’s. I’ll assume the Tesla has a 20-ton towing capacity and an optional 25-foot hatchback.

The Math

It’s pretty straightforward from this point.

Total number of charges: Distance driven/Distance per charge = 3 trillion miles / 230 (miles/charge) = 13,043,478,261 charges.

Thirteen billion recharges. Assuming a full recharge on this battery takes an hour, we would be spending 1.5 million years per year recharging. And it probably takes more than an hour to recharge. We are going to be very good at Angry Birds.

Total Electrical Energy Needed: 13,043,478,261 recharges of 60 kWh batteries is a total output of 782,608,695,650 kWh, or roughly 783 TWh.

The Verdict

Percent increase: (Power needed/Power currently produced)*100% = (783 TWh/4500 TWh)*100% = 17.4%

We’re going to have to increase our electrical output by 17.4% to meet our electrical car needs. It’s a good thing this was hypothetical — if we all suddenly switched to the Tesla Model S, we would start having brown-outs.

We could probably increase our output by 17.4% by just increasing all the individual power plants’ output by that much. But this is supposed to help the environment: maybe we could increase just the clean-burning stuff?

Hydroelectric: Water power generates about 7% of our electricity. Most (but not all) hydroelectric power comes from hydroelectric dams. There are only nine hydroelectric dams in the U.S. right now, but if we can increase that to 32, it just might work.  Are there diminishing returns on that?  How much river do you need below a hydroelectric dam before it has the inertia needed for the next hydroelectric dam?

Wind: Currently, wind power generates 3.5% of our power. If we could increase our number of wind turbines from 41,500 to 206,000, we could do it. Sorry, birds.

Nuclear: We get 20% of our power from nuclear energy coming from 65 commercial plants. We could make up the shortfall by doubling that. Probably less, since many of our plants were built in the 70s and modern designs are much more efficient. That does leave the problem of all the nuclear waste, but nuclear fission should only be a stop-gap solution until something better comes along anyway.

Provides at least 1.21 gigawatts

Provides at least 1.21 gigawatts

Also, using something hippies hate to power something hippies love sounds like a brewing crisis of conscience that should make for great television.

In conclusion — it seems as though switching everyone to an electric car is manageable, but only if we plan ahead. If you decide to get a Tesla or a similar solution, go nuts! But maybe install some solar cells on your roof too?

Now, please excuse me. I’m needed out back.

Woo hoo!

Woo hoo!


4 Comments on “Thought experiment: Electric cars vs. the environment

  1. A quick note about hydroelectric: Some water-wheels from centuries past may have depended on inertia to make power, but hydroelectric dams use gravity instead. The number you’re concerned with here is head-height.

    • I’m not clear on the difference, I’m afraid. But I’ve never worked at a dam 🙂 I understand the old-style water wheels. Do modern dams do something like collect water in some upper reservoir and then drop it straight down to generate power?

  2. The inertia/kinetic energy of the water is created by a decrease in height, which translated the potential energy of the position of the water in the gravitational field into kinetic energy, which we then convert to electrical power. It doesn’t have to be a vertical height, but the amount of energy it generates comes from the vertical vector of the drop.

    That reminds me, we would have had to drop my car off the Hoover Dam to generate the kinds of speeds they said I was going…

  3. Oh, and thanks for the calculation, I had no idea about these numbers and my guesstimates would have been all over the place.

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