SARAJEVO (Bosnia and Herzegovina), May 4 (SeeNews) – Bosnia's Elektroprivreda BiH [SAJ:JPESR] said on Wednesday it signed an annex to a contract on the construction of a 450 MW unit at the existing Tuzla thermal power plant (TPP) with a consortium of companies made up of China Gezhouba Group Co. and Guangdong Electric Power Design Institute, which foresees a drop in the net contract price by 63.3 million euro ($72.7 million).