Sep 09 2021

Electric Vehicles by the Numbers

I recently purchased a full electric vehicle (EV) and so far I’m very satisfied with the purchase. The functionality and performance is just superior, in my opinion, to similar internal combustion engine (ICE) vehicles. The up front cost is a little higher than for a similar ICE vehicle, but that difference is coming down, especially if you consider the reduced cost of operation from reduced fuel and maintenance costs. In fact, depending on the specifics some EVs may be cheaper over the lifetime of the car vs a similar ICE vehicle. According to Consumer Reports, for example:

The Tesla Model 3 is priced lower than the gas-powered BMW 330i, and priced only about $2,000 more than an Audi A4. But the savings on operating costs for the Model 3 are about $17,000 when compared with either of the popular German gas-powered sedans.

This will only get better as battery technology improves and EV mass production increases. But the primary reason many people may purchase an EV is because they believe it is better for the environment, and they are correct. However, there is often a lot of confusion over how to properly compare EV to ICE vehicles. Let’s look just at carbon footprint – EVs do require more energy to produce, largely because of their battery, so they begin with a larger carbon footprint than a comparable ICE vehicle. Exactly how much more depends, again, on lots of variables, but mostly the size of the battery. For a 300 mile range EV the upfront carbon footprint is about twice that of an ICE.

EVs, however, produce less carbon throughout its driving life. There are two ways we can look at this comparison, therefore. One is to ask, how many miles do you need to drive an EV before the carbon footprint is lower than an ICE? The second is, how do the carbon footprints compare over a typical lifespan of the vehicle? Both are complementary and informative. In either case, the EV wins out by far.

If we compare otherwise similar vehicles, the time to reduced carbon footprint for EVs depends on the source of the energy used to charge the battery. We can consider three scenarios. In the first 100% hydroelectric or other clean energy source is used to charge the car. In this case you would need to drive the EV only about 8,000 miles before an ICE vehicle would have greater total greenhouse gas (GHG) emissions. If the energy source is a typical US mix (20% coal, 20% nuclear, 20% renewables, 40% natural gas) then it takes about 13,000 miles for the lines to cross. If in the worst case scenario 100% of the electricity is sourced from coal-fired plants, then it takes about 89,000 miles.

So even in the worst case, over a typical lifespan of the vehicle the total GHG emissions are much lower for EVs than ICE vehicles. This may seem a bit counterintuitive at first. How can burning coal to make electricity, transporting that electricity and using it to charge a battery, and then using the battery to propel a car be more efficient than just burning gasoline in the car?  The simple answer is that EVs are more efficient that ICEs.

Electric motors convert over 85 percent of electrical energy into mechanical energy, or motion, compared to less than 40 percent for a gas combustion engine.

It’s just hard to beat being more than twice as efficient. Also, EVs can benefit from regenerative braking, which captures kinetic energy otherwise lost to braking to recharge the battery (and also greatly extends the life of your brakes).  Again, there are other variables here. The colder the weather the less efficient batteries are, and the waste heat from an ICE can be used to heat the car, while EV energy has to be expended to heat up the battery for better performance. But even in the worst case scenario for EVs, they still beat ICEs.

The only real downside to EV is range, but that is also improving all the time. The Tesla 3 can have a range of 350 miles, which is more than enough for most uses. For those times when you need to drive more than 350 miles in one day, there are plenty of recharging stations available (and a helpful app to show you where they are). For most uses, in fact, it is more convenient to just plug your car in when you get home rather than having to visit gas stations. We have definitely crossed the line in terms of adequate range, and this will only improve as battery technology improves and the availability of charging stations increases.

Given all this, EVs seem like the clear winner. They even beat hydrogen vehicles for most uses, because hydrogen is less efficient and there are issues with storage and infrastructure. Hybrids are better than full ICEs but not as good as full EVs.

What about the issue with LiIon battery fires? According to data from Tesla:

for the period between 2012 to 2020, there has been about one vehicle fire for every 205 million miles traveled.

ICEs are 11 times more likely to catch fire than EVs, but it is true that EV fires are harder to put out. The risk of batteries overheating and catching fire is also decreasing over time as the technology improves.

In may ways, EVs seem like the best way forward. There are definitely hurdles in the way if we want to maximize the percentage of EVs on the road, including reducing the upfront cost, increasing the number of recharging stations, and upgrading the electric grid as well as adding more energy capacity. There are also benefits beyond reduced GHGs. EVs would produce less pollution in high population density areas, which will have health benefits and reduced healthcare costs. EVs would also reduce noise in congested areas. They are already above the line in terms of being ready for widespread adoption, and the technology is improving more quickly than its competition.


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