UPDATE 1-Puerto Rico utility head Ramos resigns after slow Maria response

(Adds official confirmation, details of resignation, quotes, background)

NEW YORK, Nov 17 (Reuters) - The head of Puerto Rico's indebted utility has resigned following the slow restoration of power after Hurricane Maria, according to a statement from the U.S. territory's governor.

Ricardo Ramos, who was named head of the Puerto Rico Electric Power Authority in 2016, has resigned from the utility amid its difficulty in restoring power to the island and criticism over controversial contracts. The resignation was effective Friday, the statement said.

Maria knocked out power to all 3.4 million residents in the U.S. territory in late September, and only about half the island has been restored. The island has also experienced intermittent interruptions to populated areas that had seen electricity restored over the past few weeks.

PREPA's board will meet later on Friday to discuss who will succeed Ramos, who was appointed by Governor Ricardo Rossello.

It took a week before PREPA was able to assess the damages from the storm, which they said knocked out about 80 percent of its transmission capabilities.

Ramos was criticized for signing a $300 million contract with a little-known Montana company, Whitefish Energy Holdings, to restore power, and because he did not request aid from U.S. utilities that is a normal procedure following storms.

"The highest peak of generation that we have had is 50 percent. In this week, we had about three general blackouts in the island that kept San Juan in the dark for most of the week. That is totally unacceptable," said Tomas Torres, executive director of the Institute for Competitiveness and Sustainable Economy for Puerto Rico, a non-profit organization. (Reporting By Nick Brown and Jessica Resnick Ault in New York; editing by Grant McCool)