How many pounds of coal are needed to charge the battery in a Chevy Volt one time?...

[Philip H]

...That will get you almost 40? miles of travel or about the same as burning 7 pounds of gasoline is a similar gasoline powered car.
How does that effect greenhouse gas emissions?
Of course, the coal is burned at your local power plant.

[Eric]

There are other more complete answers (h/t breath on the wind), but just a couple other things to point out

- it takes (mostly-coal-fired-in-the-us) electricity to refine gasoline, too. So even your gasoline powered car "burns coal" in that sense.

- EVs are much more efficient per unit of energy than gasoline-powered cars. So it's hard to argue that they aren't better for the overall energy budget of the US, as long as they meet the needs of the driver.

It's a big subject of debate, but I am pretty confident that GHG's would be reduced if gas-driven-miles were exchanged for EV-driven miles, and moreso as we add renewable power to the grid.

If you want to do more reading, the source below has several papers for interest.