The average American drives 37 miles per day. EVs can travel 4 miles per kWH. That's 9.25 kWH required for the average American, every day. The average American household consume 30 kWH of power every day.

You may think we need we therefore need a 33% increase in power generation just for every household to have a single EV, but that's not quite true. We need to factor in that residential electrical usage only comprises 40% of total electrical usage. That 33% increase suddenly becomes a 13.2% increase.

Even that's not the whole picture because refining oil to make gasoline requires 5 kWH of power per gallon. Most of that power comes from burning oil, but 40% of it is coming off the grid. That's 2 kWH of power coming off the grid to refine that 1 gallon of gas. Since the average American drives 37 miles per day, we'll say they're consuming roughly 1.5 gallons of gas per day, which used 3 kWH of power from the grid to refine.

If you work it all through you end up needing an 8% increase in generation to support every single US household having an EV (and it's an additional 8% for every additional EV). Sounds like a lot, right? No. There are vast differences in the demand for power from on-peak (during the day) and off-peak (during the evening) power. Vast enough that households can charge two EVs at night during the off-peak period and still not constrain the grid.

Getting back to your question - what kind of power grid can supply electricity to a country full of EVs? The grid we already have.

Today's power grid with some upgrades. The 1910s power grid also wouldn't be able to handle today's load.

The US went from something like 10% of buildings with air conditioning to 90% in two decades. That was a harder problem than switching all gasoline cars to EV.

This question gets asked so often despite being answered that I refuse to believe that anybody asking it is actually interested in learning the answer and thinks they just have a clever anti-EV "gotcha!" question.

Most of the grid will handle it fine. People in very rural areas where it's common to only get 60 amp service might have a problem. But they probably weren't going to get an EV anyways.

Related and interesting: my local monopoly utility company RG&E is pushing for EVs hard. They stand to make a fortune if everyone all of a sudden needs to plug a car or truck into their grid.

Norways. With no upgrades. The Norwegian Water Resources and Energy Directorate has a study showing the details. That’s assuming that most people charge at night. But that’s already happening. Setting up a modern EV to charge based on electricity prices is dead simple. And since electricity is more expensive when the load on the grid is highest, people wanting to charge their cars in the cheapest way will necessarily charge in a way that doesn’t overload the grid.

Norway does have a pretty strong grid. It has primarily used electricity for heating, with some wood but not much gas. People are transitioning to heat pumps and improving insulation as well so the load on the grid from heating is actually going down too.

Other countries may eventually need some grid upgrades. But how is that an insurmountable issue? The grid has been upgraded in response to increased demands many times before.

The same battery tech going into EVs is helping improve and stabilise the grid, and helping some people reduce their energy consumption from the grid to near zero with solar+battery storage. So seems like EVs help contribute to the exact kind of R&D needed to take some of the added load off the grid.

1920: What kind of infrastructure can supply gasoline to a country full of cars? Meanwhile horse driven carriages have a strong supply chain.

The existing power grid basically with maybe some local improvements. An ev the charges while parked averages to less power than an electric kettle.