OPEC remains vital, but will struggle going forward, IEA says

North American oil output is expected to rise at the same time OPEC begins to face strong "headwinds," the International Energy Agency said Tuesday.

"By the end of the decade, North America will have the capacity to become a net exporter of oil liquids," IEA Executive Director Maria van der Hoeven said in a statement from Paris. "At the same time, while OPEC remains a vital supplier to the market, it faces significant headwinds in expanding capacity."

The Organization of Petroleum Exporting Countries said in its latest market report global oil demand is expected to increase by 1.14 million barrels per day this year. It expects the global economy will need 29.7 million barrels of its crude oil per day in 2014, a decline of 400,000 bpd from the previous year.

IEA in its annual five-year outlook report backed OPEC's estimates, noting global oil demand is expected to slow down.

The expectations for North America are in part due to increased production from shale. IEA said other countries may start to replicate the success, but said the United States is unique.