If we're going to put the brakes on climate change, electric cars will be crucial. At least, that's the general consensus: Get the heck out of that Hummer, and into something without an exhaust pipe. At least seven countries plan to ban the sale of cars with internal combustion engines sometime in the next few decades, and the specter of losing out on markets like the UK, France, and most of all China (the world's biggest car buyer) has pushed the auto industry to mobilize.

This week, Ford announced plans to introduce 24 electric or hybrid cars by 2022 (it also shared vague plans for a model called the Mach 1, which might be some sort of high performance SUV, to make that transition from your gas guzzler a little easier.) GM is already all-in on an electric future, along with Jaguar Land Rover, Volvo, and Aston Martin.

But you'll find more potholes than panaceas on the road to cleaner, greener, future. So, as we charge our batteries for a new way of driving, here are the questions we should be asking.

1. How many gas cars can we take off the road?

The countries that want bans on gas burners are huge potential markets for EV sales. If demand for personal cars stays constant, we can use current sales figures to estimate how many electric cars we will need.

2. Bring on the batteries.

Toyota and Honda are still trying to make hydrogen fuel cells happen, so far without much customer interest. So all those new EVs will rely on our current best technology, lithium-ion batteries. Fully electric models will need big ones, hybrids can get by with smaller packs, using gas engines as a backup. Tesla is projecting it'll produce 35 gigawatt-hours' worth annually, and is building the world's biggest building, the Gigafactory, in Nevada to do it. But we're going to need way more than that. Cars will soon enough replace consumer electronics as the chief consumers of batteries, and they're going to need a lot more than the things built into your smartphone.