Strange things are afoot at the Circle K. -Ted Theodore Logan
Question #92080 posted on 06/07/2019 10:06 a.m.

Dear 100 Hour Board,

So electric cars are fun, but we’re burning coal to create electricity and use a ton of carbon to make steel and batteries have really nasty metals in them so exactly how good for the environment are electric cars?

-Seriously wondering. Does all of this outweigh driving a pre-existing working car that burns gasoline?



It depends a lot on how your state generates power and what car you get. This video gives a really good breakdown that includes just how much variability there is in the market and what that means for you as a consumer.  Basically, in general, electric cars are better for the environment. But you can get it wrong when buying an electric car. Most electric cars will make up the difference within 5 years, but if that car dies before it makes up it's difference then it will be a net loss, especially if you're in a coal-powered state. 

You can find lots of people using data to claim electric cars are barely better, but I honestly would be very wary of them. Watch their videos, consider their argument. But remember that low emission countries are completely committing to electric cars. I think there is a reason it is the go-to topic when we talk about cutting emissions. 

Solving the battery problem will crack this issue wide open. In fact, it will crack a lot of environmental problems. So look forward to that, because honestly I think we're on the brink of just insanely good batteries. 



Dear Seriously,

My electric car is powered by the solar panels on my roof. No coal involved. (I don't know how they got the electricity to make my solar panels, but we would have gotten them even if we didn't have an electric car, so I'm neglecting that detail here.)

This is also not my intellectual forte, but Yellow showed me this graphic from this tweet from this source the other day, and I think it's pertinent to this conversation to see that there are some cities that are working hard to provide electricity without burning coal. This shows the UK's electricity from coal. (I just wish it were in Utah...)


~Dragon Lady


Dear Reader,

Dragon Lady's car aside, you're right in that most electric cars charge up using electricity made mostly from burning natural gas or coal. Let's take a look at how that works out.

Let's take a look at a gas-powered car that gets 25 mpg. The energy density of gasoline is 45 Megajoules (MJ) per kilogram and the mass density is 2.83 kilograms per gallon. So... 45 MJ/kg * 2.83 kg/gal = 127.4 MJ/gal * (1 gal / 25 mi) = 5.1 Megajoules of energy per mile driven. In other words, that car takes 5 million joules of energy to drive a mile. That might sound like a lot, but 5 million joules is 1.4 kilowatt hours (which cost about $0.20 each when you get them from your electric company), and is approximately the amount of energy it takes to operate an electric oven for 30 minutes or so.

Now let's look at a Tesla Model 3 (2019, Standard Range) which boasts a 50 kWh battery and a range of 220 miles. A quick calculation would yield 50 kwh / 220 miles = 0.23 kWh/mile or less than 1 million joules per mile. It's 5 times more efficient! But wait! We haven't taken into account the energy that went into the power plant to create the 50 kWh of energy. The average energy efficiency of fossil fuels is about 35%. So to make 50 kWh of energy, you need to put in 50/0.35 = 143 kWh of fuel. 50 kWh of the 143 turns into energy, but the rest is wasted as heat. Re-doing our calculation, we find that the true energy cost of a Tesla charged by fossil fuels is 143/220 = 0.65 kWh / mile which is about 2.3 Megajoules per mile. Not as good as before, but still twice as efficient as the 25 mpg car.

To get to that 2.3 MJ/mi figure, a gasoline car would need to have a fuel efficiency rating of at least 55 mpg. What's really cool about this is that 5 years ago, when I started paying attention to the electric car market, the best electric cars were about the same as a 30 mpg gasoline car. Now, the best electric cars are WAY better in terms of energy efficiency. Now, as you pointed out, there are other concerns with batteries, shelf life, etc. But electric cars are quickly making it. Awesome.


The Man with a Mustache


Dear wondering,

The other writers have covered the question of whether an electric car is actually more environmentally friendly than a gas-powered car, but your question gets at an important point: there are no truly environmentally-friendly cars. Every car is made with plastic (a petroleum product) and metal (mining uses a ton of water and can lead to some truly nasty contamination). Every car has brakes and tires, which shed toxic metal and rubber particles when used. Every car drives on roads, which are made with either asphalt (again, a petroleum product) or concrete (the source of nearly a tenth of the world's CO2 emissions). Cars strike and kill hundreds of millions of animals every year, and some species have experienced measurable evolutionary changes in response to cars and roads.

Cars are also terrible for human health. Traffic collisions are the 9th leading cause of death worldwide. Texas hasn't gone a single day without a car-related fatality in nearly two decades. Sitting for hours at a time is awful for your body. Long commutes have a demonstrable negative effect on mental health and family cohesion.

None of this is a knock against electric vehicles. I drive a hybrid, and I'd love my next car to be all-electric. But transitioning from internal combustion engines to electric motors is harm reduction, not a permanent solution. The only truly environmentally friendly alternative is to reduce vehicle miles traveled.

When we moved earlier this year, my wife and I made the conscious decision to live within walking distance of my job. I get more exercise (because let's be honest, I'd never get any exercise at all if I didn't walk to work), and we don't have to sink thousands of dollars into a second car. This is only possible because California has been moving towards allowing higher-density development, in our case an accessory dwelling unit. We could never survive with just one car if we still lived in Utah.

If we're going to be serious about reducing our environmental impact, we can't just move to a different, less damaging form of consumption. We have to actually reduce our consumption. And in order to do that, we need to seriously reconsider some of our assumptions about the role of cars and the way we build our cities.