Philippine senators have called for an investigation into the security implications of China’s part ownership of the national energy grid after officials said engineers in Beijing could black out the entire country with the flick of a switch.National Transmission Corporation (TransCo) president Melvin Matibag confirmed there was a “possibility” of such a scenario during deliberations in the Senate on Tuesday over the government budget for 2020.The State Grid Corporation of China holds a 40 per…