LONDON — The United States will become almost self-sufficient for its energy needs by 2030, boosted by shale oil and gas output and slowing demand, British energy giant BP forecast on Wednesday.

"By 2030, increasing production and moderating demand will result in the United States being 99-percent self-sufficient in net energy; in 2005 it was only 70-percent self-sufficient," BP said in its latest Energy Outlook report.

"Meanwhile, with continuing steep economic growth, major emerging economies such as China and India will become increasingly reliant on energy imports. These shifts will have major impacts on trade balances."

The London-listed giant added that the rapid growth of unconventional energy sources -- like shale gas and oil which is extracted from low-pressure fractures in the ground -- would redraw the global energy landscape.

"Strong growth in production from unconventional sources of gas and oil will have a major impact on global energy markets to 2030, redefining expectations for major economies and rebalancing global trade flows," it said.

Unconventional oil sources were meanwhile forecast to provide all of the net growth in global oil supply needs until 2020, and more than 70 percent of growth to 2030, according to BP.

The Paris-based International Energy Agency had in November forecast that the US would become the world's top oil producer over the course of the next two decades, overtaking Saudi Arabia on the back of surging shale oil and gas output.

Wednesday's report was published on the same day that Al-Qaeda militants from Mali attacked a gas field run by BP in southern Algeria, killing one person and kidnapping one French and four Japanese staff, officials said.

The attack appears to be the first reprisal against Western interests for a French-backed offensive against jihadists in neighbouring Mali.