Natural gas will overtake coal as a global energy source in the middle of the next decade, in part because of the environmental benefits it offers, according to ExxonMobil , the world’s largest oil and gas company. In its annual forecasts of the energy outlook for the next three decades, published on Thursday morning, Exxon says that around 2025 gas will become the world’s second most-used fuel on an energy-equivalent basis, behind oil. By 2040, it expects natural gas consumption to rise 65 per cent, but coal use to be no higher than it is today, rising and then falling again during the next two decades. The forecasts sketch out the battleground for a contest between gas and coal to be the dominant fuel for power generation. Exxon is significantly more negative about the outlook for global coal use than other forecasters. The International Energy Agency, the think-tank backed […]