The self-guided tour inside the World of Energy at the Oconee Nuclear Station provides a pretty darn interesting look at electricity and how it has been produced in the region, from the use of water power to coal to uranium. The nuclear plant went online in 1973, and has since generated more than 500 million megawatt-hours of electricity.
There's also a lovely nature trail that runs along Lake Keowee, with a picnic area that makes for a perfect lunch spot.