Nobuo Tanaka, executive director of the International Energy Agency, said new natural gas discoveries in the United States and similar global trends in liquefied natural gas suggested the energy outlook was good.
Tanaka said non-conventional gas supplies such as shale made the United States the world's biggest gas producer in 2009. Meanwhile, similar developments in LNG translated to an estimated 50 percent increase in new gas supplies "over the next few years" compared with 2008 levels.
"While the outlook for gas supplies may thus appear relatively comfortable, we cannot afford complacency," said Tanaka. "We must push forward now with new investment."
Oil demand, the IEA director said, is expected to increase at an annual rate of 1.4 percent, reaching 92 million barrels per day by 2015. This means oil capacity could fall to less than 5 percent of the global demand, however.
Tanaka said oil and gas markets are showing signs of recovery but the outlook for energy remains uncertain.
"This is not about an inadequate resource base in either oil or gas," he said, "but about timely and adequate investment."