Internet titan Google and technology colossus General Electric said Wednesday they are joining forces to promote a "smart" US electric power grid and clean energy policies.

The companies said they will work together on green energy technologies and lobby US political leaders to support "visionary policies" on renewable energy.

"Both companies believe that our economic, environmental and security challenges require that we use electricity more efficiently, generate it from cleaner sources, and electrify our transportation fleet," the US firms said in a joint release.

"This 21st century electricity system must combine advanced energy technology -- a major GE focus -- and cutting edge information technology -- a major Google focus."