Romania's Petrom opens 860 MW power plant

* Can cover 8-9 pct of Romania electricity market

* Started production on Wednesday

BUCHAREST Aug 2 (Reuters) - Romania's Petrom has started to produce electricity at its 860-megawatt Brazi gas-fired power plant, which could supply 8-9 percent of the country's market, it said on Thursday.

The plant, initially scheduled to start operations at the end of last year, is the first foray into the local electricity market by Petrom, the country's largest oil and gas company, which is majority-controlled by Austria's OMV.

"Starting August 1, 2012, the plant can deliver on a commercial basis electricity to the national grid," Chief Executive Mariana Gheorghe said in a statement.

"Operated at maximum capacity, the power plant could cover 8-9 percent of the electricity market."

It is the largest investment in the country's predominantly state-owned power production sector since a second nuclear reactor was connected to the national grid in 2007.

Petrom is also working on a wind energy park. (Reporting by Sam Cage and Luiza Ilie; Editing by Anthony Barker)