Abu Dhabi's Mubadala Energy aims to double output over the next decade, with natural gas accounting for about 70 per cent of its portfolio, its acting chief executive has said. Mubadala Energy, a unit of Abu Dhabi's sovereign wealth fund, is exploring investment opportunities in the natural gas value chain, with a number of ventures forged to boost the portfolio, Adnan Bu Fateem told state news agency Wam.