The global thirst for oil will grow in the next two decades driven by demand from emerging nations and the rise of the United States as the world's top producer, the International Energy Agency says.
Oil demand will increase by 14 per cent between now and 2035 to reach 99.7 million barrels a day, the OECD-linked energy watchdog said in its annual assessment of the energy markets of tomorrow.
This was 700,000 bpd more than the IEA forecast a year ago and signals that the world is still figuring out how to put the global energy system on a more sustainable path, the IEA said.
Oil prices will rise, too, it said, reaching $US125 barrels by 2035 ($US215 in nominal terms), from about $US107 this year, instead of the $US120 forecast earlier.
"Growth in oil consumption in emerging economies, particularly for transport in China, India and the Middle East, more than outweighs reduced demand in the OECD, pushing oil use steadily higher...," the IEA said.
Transportation "is responsible for almost 40 per cent of the increase in global oil demand", the agency said, with oil use for trucks - mainly diesel - increasing much faster than that for passenger vehicles.
In its new scenario, the IEA believes the US will become the world's top oil producer by 2020, overtaking Saudi Arabia until the mid 2020's.
"The recent rebound in US oil and gas production ... is spurring economic activity ... and steadily changing the role of North America in global energy trade," the agency said.
Up until 2035, "the United States, which now imports around 20 per cent of its total energy needs, becomes all but self-sufficient in net terms - a dramatic reversal of the trend seen in most other energy-importing countries."
The US energy market is going through radical upheaval sparked by the development of new technologies, especially the extraction of shale gas through a controversial process called "fracking" that has been limited or banned in other countries.
On the supply side, the IEA sees a decade long decline in the dominance of OPEC on the back of unconventional production from non-cartel countries.
Non-OPEC oil supply should reach 53 million bpd after 2015 (from 49 mbpd in 2011) in a supply rise that should end in 2025, when OPEC production will again dominate.
"Output from OPEC countries rises, particularly after 2020, bringing the OPEC share in global production from its current 42 per cent up towards 50 per cent by 2035," the IEA said.
The key to OPEC output over the coming decades is Iraq, the IEA said, which could make the "largest contribution by far to global oil supply growth".
The IEA believes that if political stability is achieved, Iraq will become "a key supplier to fast-growing Asian markets, mainly China, and the second-largest global exporter by the 2030s, overtaking Russia".
"Without this supply growth from Iraq, oil markets would be set for difficult times, characterised by prices that are almost $US15 higher" than the level tabled in the outlook.
Natural gas demand worldwide will grow in any scenario, though the outlook varies by region, the IEA said.
In the US, the emergence of shale gas will bring on a fall in coal demand, the IEA said, while in Europe, where gas prices are on the rise, coal-based energy is increasing, the IEA said.
Renewable energies should grow, becoming a source of about one third of world electricity by 2035, but the IEA revised lower its outlook for nuclear energy following the 2011 Fukushima disaster in Japan.
The trend for coal demand over the next decades is uncertain, the IEA said, largely dependent on policy measures towards reducing carbon emissions and the development of carbon capture storage technology.