Scientists say they are looking to the sun for energy to help U.S. Marines do away with diesel-guzzling generators now used in combat outposts.

Researchers at the Office of Naval Research say a hybrid system using solar power could provide Marines with electricity for a 15-day mission without relying on fuel resupply convoys that often become targets for adversaries.

Three industry teams led by Raytheon, Battelle and Emcore have been enlisted to develop concepts for hybrid systems that use sunlight, heat and fuel to create electricity, an ONR release reported Thursday.

The systems must be smart enough to independently switch back and forth from solar when the sun is out to fuel at night or when there is heavy cloud cover, the release said.

"This is a very interesting multidisciplinary problem we're trying to solve," program manager H. Scott Coombe said. "There are multiple heat transfer issues as well as optical, electrical and control/optimization challenges."

The hybrid system must also be compact enough to fit on a small trailer towed by a Humvee so they can be hauled to forward positions, researchers said.

"This program takes on a number of power-related challenges and ultimately will allow the Marine Corps to take a big step toward its goal of using fuel only for mobility purposes by 2025," Coombe said.