UPDATE 1-Curacao oil refinery online after power outage

(Adds background on refinery, paragraphs 5-7)

WILLEMSTAD, April 10 (Reuters) - A 320,000 barrels per day oil refinery on Curacao, operated by Venezuela's state oil company, was back online on Thursday after a power outage a day earlier, refinery spokesman Donald Cijntje said.

The refinery was without power due to a problem at the supplier utility company for most of Wednesday and suffered millions of dollars of losses, he said.

Power was restored "in the late hours" of Wednesday and the refinery quickly began operations again.

On Wednesday, residents living near the Isla refinery on the Caribbean island close to Venezuela's coast said they saw larger-than-usual plumes of black smoke rising from the refinery just outside the capital Willemstad, the radio reported. Some office buildings nearby were evacuated.

Venezuela's state company, PDVSA, operates the refinery which residents repeatedly say causes environmental damage in the area.

PDVSA has suffered power outages and accidents regularly at its refineries in Venezuela as well as at Isla in the last few years.

On Wednesday, Venezuelan Oil Minister Rafael Ramirez said he was not aware of any problems at the refinery. PDVSA officials on Thursday were not available to comment on the outage.

(Reporting by Irasi Jimenez in Willemstad and Deisy Buitrago in Caracas; Writing by Saul Hudson; Editing by David Gregorio)