Go-to mounts need power to slew (er, that's techy speak for "move around"), not only to find the target, but also to track it as you watch. More sophisticated setups will have cameras, dew heaters, auto-focus mechanisms, and all manner of geekiness.
Sky-Watcher, saxon and Celestron mounts all require 12 volt power. They normally come with a cable that ends in a cigarette lighter attachment. The question people ask us is what to do with this? Well, you can set up your telescope near your car - which isn't such a bad option - but it's better to have a battery or power supply.
A powertank - a large battery with some extra attachments - will power your scope and mount all night. You can get extra large capacity ones which will last up to a week if you're careful. What's more, the good ones have cigarette lighter outputs, so you simply plug your mount's cable into the powertank.
If you're at a more permanent location, or have a mains output near the scope, you can get a power supply that puts out 12V, but you need a connector for the mount cable. If you're good with a soldering iron, you can make up your own cable. My advice is to test the power output with a multimeter before connecting it to an expensive mount though.