So I did some simple calculations to see how many vehicles the national grid could cope with today if they all charged after midnight.

Some simple input assumptions: the average Australian driver travels around 15,000 km per year or 41 km per day. If that was in an EV with efficiency of 150 Wh/km, that's an energy need of 6.2 kW - or less than an hour's charging with a 7 kW charger or 2.6 hours off a 10A wall socket. Let's assume an average charge rate of 3.6 kW.

The average national grid load at midnight is 24.1 GW, declining to a minimum of around 19 GW around 4am, and doesn't get back to 24 GW until around 8am. So provided all vehicles can be charged to restore their average daily usage within those 8 hours (a very safe assumption), then the headroom between the midnight load and total grid capacity would allow a certain number of EVs to be charged without requiring any grid expansion.

Australia's national grid capacity is at least 33 GW (the highest recent peak was 33.035 GW at 6:30pm on 14 July). Based on that, we have grid headroom of at least 9 GW to charge EVs after midnight.

So at 3.6 kW charging, Australia today could support

**2.47 million EVs**- or about 12% of the current national fleet of around 20 million vehicles. Dial the charge rate down to 2.4 kW and the number would increase to

**3.7 million**or 18.5%. Dial the charge rate down even further to use the full 8 hour window to charge, and the number increases to

**11.6 million**or 58% of the fleet. Optimise to the max (e.g. use the variable headroom available midnight to 8am and optimise the charge rate of every EV over that time) and the number gets to around

**14 million**(70%).

So what to make of this?

First, Australia is a long way from having this many EVs on the road, so this is not an urgent problem to fix. More grid capacity is added every year, so it may organically be able to keep up.

I think the grid definitely needs to get smarter, with utilities being able to use V2G to optimise the charge rate of the EV fleet to manage total grid load. Simply building capacity for more peak load is economic madness, when smarts could eliminate the need to build much at all.

But also as solar penetration increases and more households add batteries, that will enable more EV charging to happen "behind the grid" hence reduce the incremental grid load as well. And EVs might get more efficient than 150 Wh/km. And people might drive less post-Covid with more WFH. Lots of things could change.

So there are some challenges ahead, but it looks absolutely do-able to me over decade-type timeframes, and the advent of EVs will not bring grid Armageddon.