* Japan's Hitachi and Chinese consortium still in running
* A consortium led by Spain's Cobra ruled out
* The winner to be picked by the end of the year
* Project estimated to cost $1.14 bln (Adds quote, detail)
SARAJEVO, Sept 26 (Reuters) - Two bidders remain in the running to build a 450 megawatt (MW) coal-fired unit at the Tuzla power plant in Bosnia, an official at the country's top power utility EPBiH said on Thursday, adding a third bidding consortium had been dropped.
The two are Japan's Hitachi and a Chinese consortium which includes China Gezhouba Group and Guandong Electric Power Design, Enver Agic, the president of EPBiH's supervisory board said by telephone.
A third bidding group led by Spain's Cobra, a technology subsidiary of infrastructure firm ACS, which also included Toshiba, a unit of Hungary's state-run power firm MVM and Poland's Rafako, had been ruled out, he added.
"The bid by the Cobra-led consortium has been dropped from the contest as it failed to submit necessary documentation," Agic said.
He added that EPBiH should pick the winner from Hitachi and the Chinese consortium by the end of this year.
The cost to add the new unit at the Tuzla power plant is estimated at 1.65 billion Bosnian marka ($1.14 billion). The plant in northern Bosnia currently has six units and produces around 3,000 gigawatt-hours (GWh) of electricity a year.
The project will be one of the largest investments into the Balkan country's energy infrastructure, which needs upgrading as many of its coal-fired plants are way past their prime.