Ralph Wilson/AP All current projections point to natural gas as the fastest-growing fossil fuel in the energy mix for decades to come. All of Big Oil’s five are betting on natural gas in the future. Until 2022, the IEA sees gas gaining a firmer foothold in South and East Asia as the availability of ample, competitively priced supply would help to expand opportunities. Lower-for-longer oil prices and the advance of renewable energy and electric vehicles have made Big Oil plan for a gradual shift toward natural gas in their production portfolios.