Puerto Rico Electric Power Authority

The court has left in place its decision affirming the bondholders lien on net revenues.

The outage began at 5:30 a.m., leaving about 1.3 million of Puerto Rico's 1.4 million customers in the dark, according to Luma Energy, the private company that operates the system. Crews have begun restoring electricity in some areas, but it may take 24 to 48 hours to fully resume service, officials said.

The continued delay in resolving the case raises constitutional concerns, a bondholder attorney said.

Calling it a "tragedy" for residents, without a negotiated setllement resolution could be years away, mediators said.

PREPA says it is short on money and Genera's parent company has said it may go out of business.

After losing its first appeal, the Puerto Rico Oversight Board initiated a second appeal with the First Circuit Court of Appeals.

The court affirmed its earlier decision, which means bondholders have a claim on the full $8.5 billion due.

Some analysts question how much a leftist governor would impact financial and bond issues.

Oversight Board says the non-consenting bondholders ideas are "not a proposal."

Puerto Rico's electric reliability is likely to continue to deteriorate without access to the capital markets, the investors said.