By Valerie Volcovici and Nichola Groom

WASHINGTON/LOS ANGELES, Sept 30 (Reuters) - Hurricane Maria destroyed Puerto Rico's antiquated and bankrupt electrical system, leaving millions in the dark and utility crews scrambling to help.

Now some politicians and renewable energy investors see a golden opportunity in the crisis to use federal funds to re-invent the U.S. territory's grid as a storm-resistant network that relies less on costly coal and oil imports and more on local wind, solar, and batteries.

If it happens, it could ease power bills on an island that struggles with the second-costliest electricity in the United States, behind Hawaii, as well as infrastructure prone to failing in the region's frequent hurricanes.

"We cannot waste the opportunity of this crisis and federal aid package," said Ramon Luis Nieves, a Puerto Rican politician in the Popular Democratic Party, who headed the island's senate energy committee until his term expired in January.

"We need to focus on not only getting the grid back up, but improving it so it can tolerate more renewable energy."

A set of bills introduced this week by U.S. Democratic Senator Ron Wyden of Oregon would call on the Department of Energy to make the U.S. electric grid hardier against natural disasters, and would offer grants for small scale, grid connected solar and other projects.

A Wyden aide said Puerto Rico's utility, the Puerto Rico Electric Power Authority (PREPA), could apply for such grants to modernize the grid, or get funds from the Federal Emergency Management Agency to rebuild and then apply for the grants to help pay for upgrades.

Efforts to reach a PREPA official were not successful.

That government support would be crucial. PREPA was $9 billion in debt before declaring bankruptcy in July. Its equipment was already "degraded and unsafe," according to a draft fiscal report the company filed in April.

Around half of Puerto Rico's electricity is generated from imported fuel oil, with another third coming from natural gas, and much of the rest from coal, according to the Department of Energy.

Renewables supply about 2.4 percent, though the island has set a goal to obtain 20 percent of its electricity from renewables by 2035.

FUTURE GRID

The prospect of a new grid in Puerto Rico has some renewable energy companies and investors interested. Jeff Ciachurski, CEO of Greenbriar Capital, a renewable energy investor in Puerto Rico, California and Arizona, said government support could open up new opportunities for the sector to take over market share.

"The federal government is in the driver's seat," he said.