A worker is seen at a power station in a file photo. The world’s second-largest utility, GDF Suez SA, has obtained regulatory approval to buy a 50-percent stake in two power plants owned by Greece’s GEK Terna Group as part of a joint venture to tap growing demand for power in Greece. ‘All regulatory approvals have now been obtained and all conditions have been satisfied,’ the Greek company said in a filing Wednesday. GDF Suez became a shareholder in the two companies that will run the Heron I and Heron II power plants. The 150-megawatt Heron I plant, about 120 kilometers north of Athens, has operated since 2004. The Heron II 450-megawatt combined-cycle gas-fired plant is scheduled to begin operating in early 2010.