Scientists in California say they're trying to replicate the power of the sun by firing laser beams at a tiny pellet of hydrogen.

Physicists at the National Ignition Facility in Livermore say the nuclear fusion experiments may offer the world a clean source of energy, The Times of London reported Sunday.

The hydrogen pellet will be hit with 192 laser beams capable of generating 500 trillion watts -- 1,000 times the power of the U.S. national grid, said the scientists.

"We hope the ignition experiments will show that we can generate more power than we put in and that fusion can be the source of a supply of carbon-free energy," said Ed Moses, director of the facility.

Science is at least 25 years away from building fusion power stations that could provide a clean alternative to fossil fuels. Those power stations would use hydrogen atoms extracted from sea water as fuel to generate carbon-free electricity with minimal radioactive waste, Moses said.