Tenaga Nasional Berhad has bought a 49% stake in the Blyth Offshore Demonstrator to partner with EDF Renewables UK. : Tenaga Nasional Berhad has bought a 49% stake in the Blyth Offshore Demonstrator to partner with EDF Renewables UK Sign up to The Climate Agenda - the one-stop shop for green businesses and those fighting climate change A south-east Asian energy giant has bought a near-half share in a demonstrator wind farm off the coast of Northumberland.