system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: If electric vehicles are the way to go to reduce emissions, wouldn't charging them use up a lot of power, therefore still being costly and polluting? How does it work?

I know very little about today's climate actions despite routing for them, so I just want to take an opportunity to better understand them. How some things may just be temporary solutions or revolutionary ones.

I do not want climate change debates, I just want to know if powering electric cars has its trade offs or are really going to help.

EDIT: Woah, this my most upvoted and answered post since joining the site. And by a huge margin too. I really only expected like two comments.

Thank you all so much for all the answers, they've been very informative!
gpt
There are really 3 answers to this question.

1 - You might not be using a source that pollutes.  Maybe you get your electricity from solar, or hydroelectric.  This is not a very satisfying answer because it doesn't apply to everyone.

2 - Large power plants are much more efficient than a car engine.  If you burn 1000 gallons of gasoline at a powerplant and send it to 1,000 cars, you'll get more miles than if each car burned just one gallon of gasoline.

3 - Electric cars have regenerative brakes.  Regenerative brakes are great.  Imagine you're riding a bike down a hill and then up a hill... it's much easier if you can build up speed and then coast up the hill, only pedaling a little.  Well, regenerative brakes are something like that - recapturing energy and then letting you use it later.  Regular brakes on cars just turn the energy to heat - like riding a bike down a hill, stopping at the bottom, and having to pedal back up.  You don't get to reuse any of your old energy.  And theoretically you could just put regenerative brakes into gas powered cars... but then you would need to load up the car with batteries, and then you'd have a hybrid vehicle.  

So, #2 and #3 definitely have a real impact for everyone, even if #1 only impacts some people.