stands for electro-motive force
and is the exact same thing that runs your fridge
, and even this thing you are staring at right now
It is what you pay the folks at the Springfield Nuclear Power Plant for. If you live in Springfield of course, and your local electric co. elsewhere.
If you haven't gotten it yet, EMF is electricity.
Electricity is actually caused by movement, hence electro-motive, of electrons along a conductor.