Microsoft just struck a deal with Constellation Energy to receive energy from the Three Mile Island nuclear site in Pennsylvania. The agreement means that a unit that was shut down five years ago for economic reasons will be restarted.

Constellation said Friday the company has a 20-year deal with Microsoft to restore the Three Mile Island's Unit 1 nuclear power reactor, the site of an infamous nuclear power meltdown.

Constellation Energy (CEG) signs a 20-year power purchase agreement with Microsoft to pave the way to revive a unit of its Three Mile Island nuclear power plant in Pennsylvania.