Singapore state investment firm Temasek Holdings is in talks to buy a stake worth $170 million in GMR Infrastructure Ltd.'s energy unit, a person familiar with the situation said Wednesday. “Temasek is one of around five companies that have shown interest in GMR Energy,” the person, who declined to be named, said. “They've been talking since last year.” GMR Infrastructure, the listed unit of GMR Group, has said in October it is planning to sell a 10% to 15% stake in the energy unit and may offer shares through a private placement and an initial public offering. GMR group Chief Financial Officer A Subba Rao declined to comment on a potential deal with Temasek, saying it is not the company's policy to reveal any details on a deal until it reaches a definitive stage. […]