How Cars Work · By the Time You Drive
The car that powers your house
Here is something you might not have heard about. Some EVs can run in reverse — but not in the way you might think. They can pull power out of their giant battery and feed it back into the house.
Remember from Chapter 9 that an EV battery holds 50 to 100 kilowatt-hours of energy. A typical American home uses about 25 kWh of electricity per day. Which means a fully charged EV holds enough energy to power a house for two to four days.
Some EVs already support this. The Ford F-150 Lightning and a few others can be plugged into a special outlet that lets the car power your house during a blackout. Charge the car overnight when electricity is cheap, drive around during the day, and at night it powers your fridge and lights, especially if the grid goes down.
The next step is more interesting. Imagine if every EV on a street could, all at once, push a little power back onto the grid when the grid needed it — say, on a hot summer afternoon when air conditioners are pulling more electricity than the power plants can supply. A few hundred EVs charging at home can match the output of a small power plant. Some companies and cities are starting to experiment with this. The technical name for it is vehicle-to-grid, or V2G. By the time you drive, your car might not just be a car. It might also be part of a giant battery for your city.
Maybe fewer cars
The other big change is harder to see, but it might matter most. People in many cities are using cars less.
E-bikes — bicycles with small electric motors that help you pedal — are exploding in popularity. They go about as fast as a slow car (around 20 miles per hour), don’t need a driver’s license, don’t need parking, and cost a tenth what a car costs. In Amsterdam, Copenhagen, and increasingly in places like Brooklyn and Portland, more and more people just don’t use a car much in the city. They take an e-bike or a regular bike, ride to a train station, take the train downtown, and ride to the office.
Ride-sharing apps — Uber, Lyft, the self-driving taxis we just talked about — let people get rides without owning anything. Some young people are already choosing not to get a driver’s license at all, because they don’t see the point. Cities are improving public transit — better trains, better buses, more reliable schedules.
Will you own a car when you grow up? Possibly. Probably, if you live in most of the United States, where towns are spread far apart. But maybe not, especially if you live in a city. The thing called a “car” in 2040 might still be a personal vehicle that lives in a garage, or it might be a service that picks you up when you ask, or it might be an e-bike that you ride to a train. Cars are not going to disappear, but the question of how big a part of your life they are is genuinely changing.
Try It: Count EVs
On your next car ride with your mom, take a notebook. Mark down every car you can identify as electric or hybrid for the whole trip.
Some clues that a car is electric or hybrid:
A Tesla logo (a stylized “T”) on the front or back. All Teslas are electric.
A small plug symbol on the back, often near the brand name.
The words EV, Electric, Hybrid, or Plug-in printed on the back.
Brand names like Polestar, Rivian, or Lucid — these companies make only electric cars.
Some specific models that are always electric or hybrid: Toyota Prius, Honda Insight, Chevy Bolt, Nissan Leaf, Ford Mustang Mach-E.
Over a 15- or 20-minute drive, count how many you see, and how many gas-only cars you see. The proportion will tell you what kind of neighborhood you are in. Some places are well over 30% EVs already. Some are still under 5%.
Now do this once a year for the next few years. The number will keep going up. By the time you drive, EVs probably will not be unusual at all. They will just be cars.
Did You Know? Around 1900, a journalist in New York City wrote that the streets would soon be impossibly clogged with horse manure. Horses were everywhere. They pulled milk wagons, buses, police carts, family carriages. Each horse produced about 25 pounds of waste per day. New York’s streets were so filthy that walking them in nice shoes was a daily problem. Then, between roughly 1900 and 1920, almost all the horses disappeared from American cities. The car had arrived. The whole change took about twenty years. To people in 1900, gasoline cars were a strange and untrustworthy novelty — loud, unreliable, expensive. By 1920, they were everywhere, and horses had been pushed almost completely out of the cities. People who had said in 1905 that their grandkids would still ride horses to school turned out to be wrong. The transition you are watching now — from gasoline cars to electric ones — is similar in some ways and different in others. It is happening more slowly (probably 30 to 40 years rather than 20). It is happening unevenly (much faster in China and Norway than in the United States). And it might never finish completely; some gas cars will probably stick around for a long time. But the basic shape — a new technology gradually replacing an old one because the new one is better in enough ways — is one that has happened many times before.
The box is open
At the start of this book, I said we were going to open the box. The car as a sealed mystery, just a thing that moves with you sitting inside it.
The box is open now.
The pistons are firing. The mixture is being mixed. The spark is bouncing across the gap inside the cylinder. The wheels are turning through gears and a driveshaft and a differential. The brakes are converting energy into heat. The computers are watching every wheel hundreds of times per second. Or — in the electric version of all this — the battery is sending current to the motor, the motor is pushing the wheels, and when the car slows down, the energy is going back the other way.
Whatever the cars look like by the time you drive, the same physics applies. Energy stored somewhere gets converted into motion. Tires grip the road through friction up to a limit. Brakes do something with kinetic energy, whether they make heat or store it back into a battery. Steering uses geometry to point the wheels. Computers watch and decide and act.
Pistons and crankshafts and carburetors might all eventually become history, the way horses became history. But a car will still be a metal box on four wheels, with seats and windows and a steering wheel, taking people from one place to another. The basic experience of being a person inside a car has been the same for over a hundred years. It will probably be the same in 2050.
You started this book as a passenger. You still are. But now you know what is happening around you when you ride.
You don’t drive yet. That’s fine. You don’t need to drive to understand a car, the same way you don’t need to fly a plane to understand how a wing works. You just need to pay attention.
Now you know what to pay attention to.
Questions to talk about
No answer key. These are for arguing over, with someone who read the same chapter.
- The author deliberately refuses to predict, pointing out that in 1900 experts said there would never be more than a few thousand cars. Why are confident predictions about technology so often wrong?
- Batteries improve roughly 7% a year — small annually, large over a decade. What else changes at a rate too slow to notice year by year but obvious across ten?
- The book ends by saying that whatever cars become, the same physics applies: energy stored somewhere turns into motion, tyres grip up to a limit, something must be done with kinetic energy. Which idea from this book do you expect to still be true when you are old?