"Over the past several decades oil has been the world's foremost source of primary energy consumption, and it is expected to remain in that position," the federal Energy Information Administration said in its forecast.

OPEC producers are expected to be the major source of the additional oil that will be needed, with the cartel's output more than doubling from the current 27 million bpd to almost 56 million bpd by 2025.

However, oil production will also increase from non-OPEC suppliers located in the Caspian Sea region, Latin America and west Africa, according to the EIA.

Oil's share of world energy use will only drop slightly from the current 39 percent to 38 percent by 2025, although many countries will switch from oil to natural gas and other fuels to run their electric generating plants.

The jump in oil demand will be due to the strong growth in transportation sector - which accounts for the majority of crude use.

While industrialized countries continue to consume more of the world's petroleum products than developing nations, the gap is projected to narrow during the forecast period.

Developing countries use about 64 percent as much oil as the industrialized nations, and by 2025 their consumption will increase so that it will be 86 percent, EIA said.

The fastest growing energy source over the next two decades is expected to be natural gas, which is forecast to increase 2.8 percent a year and nearly double to 176 trillion cubic feet annually by 2025.

Natural gas' share of total energy consumption is forecast to increase from the current 23 percent to 28 percent by 2025, as gas burns more cleanly and efficiently in new power plants and is a more attractive choice for countries that want to reduce their greenhouse gas emissions.

Coal use will grow only 1.5 percent a year, accounting for a shrinking share of world energy consumption as it falls from 24 percent to 22 percent by 2025.

However, coal demand is expected to grow in China and India, where it continues to dominate many fuel markets.

Nuclear power is forecast to suffer the biggest decline as an energy source over the next two decades, with its share falling from 19 percent of the world's total electricity generation to 12 percent.

"Although some nations are expected to construct new nuclear power plants during the forecast period, declines in nuclear capacity are projected for most of the countries with active nuclear power programs as older plants are retired," EIA said.

Hydroelectricity and other renewable resources, like solar and wind, are forecast to increase moderately, growing 1.9 percent a year by 2025 due mostly to the Three Gorges Dam hydropower project in China.

"Renewable energy sources are not expected to be economically competitive with fossil fuels (oil, natural gas and coal) in the mid-term without significant support from government policies that would encourage their widespread expansion," EIA said.