Global energy demand growth will halve by 2025 but fossil fuels will continue to dominate, leaving the planet on a warming trajectory of 3.6 degrees, according to the International Energy Agency.

Australia, though, stands to benefit from rising anguish over energy security, with buyers of gas and coal vying to lock in supplies from an established democracy amid rising tensions in the Middle East and between Russia and Ukraine, the IEA said in its influential World Energy Outlook 2014 report.

Australia's share of the global energy market will grow, with the country becoming a top-three gas producer and reclaiming its title as the world's largest coal exporter, Fatih Birol, the IEA's chief economist told Fairfax Media in his only interview with the Australian media.

"The growth of Australian gas exports is welcome news for the rest of the world," Dr Birol said.

Relatively good news on the climate front is that energy demand will expand by 1 per cent a year by 2025, half the pace of the past two decades. Growth will be concentrated in China, India, the Middle East, Africa and Latin America.

Consumers will also increasingly favour lower emissions-intensive gas over coal, in part because of local pollution concerns. Even so, carbon-dioxide emissions blamed for global warming will grow by 20 per cent by 2040 with overall energy demand rising 37 per cent.

By then, the world will have exhausted its entire CO2 budget of 1000 gigatonnes – the amount of emissions estimated by the UN's Intergovernmental Panel on Climate Change to keep temperature rises to within 2 degrees.

"Since emissions are not going to drop suddenly to zero once this point is reached, it is clear that the 2-degrees objective requires urgent action to steer the energy system on to a safer path," the IEA said.

The challenge will be the focus of the UN's Paris climate summit planned for late 2015.

Energy security

However, other challenges, such as energy security, will most likely set national priorities.

Energy poverty will also foster continued reliance on lower-cost carbon fuels, with electricity now available to only one in three sub-Saharan Africans, the IEA said.

As a AAA-rated nation in debt markets and an established democracy, Australia is well placed to benefit from rising demand but will need to lure $US1 trillion ($1.15 trillion) in new investments to meet demand for its energy.

"We expect the gas to become the first fuel, overtaking oil [globally] by about 2040," Dr Birol said.

While gas now costs twice as much as coal to produce the same amount of electricity in Asian markets, demand for cleaner fuel will drive change in the industry.

"I know that many governments are putting policies in place to address local pollution challenges which will, of course, help the gas industry," Dr Birol said.

He predicts Australia's gas production will increase from about 60 billion cubic metres a year to more than 150 bcm by 2025, placing the country third behind the US and Russia. Output should edge higher to 170 bcm by 2040, Dr Birol said.

Coal, gas and oil should make up about 75 per cent of global energy supply by 2040, roughly divided equally between the three.

Renewable energy will continue to increase its share but faces headwinds including annual fossil-fuel subsidies of $US550 billion ($633 billion) outweighing clean technology assistance by more than four-to-one, the IEA said.

Globally, the demand for coal will rise by 15 per cent by 2040, with most of the growth coming in the next decade.

India will be the big mover, overtaking the US as the second-biggest coal user before 2020 and will be the world's biggest importer – nudging out China – soon after that, the IEA said.

Australia will benefit here too, Dr Birol said.

"We expect Australian coal exports to increase substantially and will take back the throne as the largest coal exporter from Indonesia before 2030," he said.

The French-based IEA was set up following the oil crisis in the 1970s. It now has 29 member nations, including Australia.