World marketed energy consumption is projected to grow by 50 percent from 2005 to 2030, the United States Energy Information Administration (EIA) reports in its recently released International Energy Outlook 2008.

The increase in consumption, according to the EIA, is driven by a number of factors, including robust economic growth, expanding populations in the world's developing countries, no growth in production since 2005 from the members of the Organization for Economic Cooperation and Development (OECD), rising costs for oil exploration and development, across-the-board increases in commodity prices and a weaker U.S. dollar.

The most rapid growth in energy demand over this period is projected for nations outside the OECD. Total energy demand in the non-OECD countries increases by 85 percent in the latest projection, compared with an increase of 19 percent in OECD energy use.

"In all the non-OECD regions combined, economic activity (as measured by GDP in purchasing power parity terms) increases by 5.2 percent per year on average, as compared with an average of 2.3 percent per year for the OECD countries," the EIA report states.

Fossil fuels — liquid fuels and other petroleum, natural gas and coal — are expected to continue supplying much of the energy used worldwide. Liquids supply the largest share of world energy consumption over the projection period, but their share falls from 37 percent in 2005 to 33 percent in 2030, largely in response to a reference case scenario in which world oil prices are expected to remain relatively high.

Although liquid fuels are expected to remain the world's dominant source of energy through 2030 — due in large part to the transportation and industrial sectors — the liquids share of marketed world energy consumption is projected to decline from 37 percent in 2005 to 33 percent in 2030.

In addition, the share of conventional oil in the overall liquids supply is expected to decline, with expanded use of oil sands, extra-heavy oil, biofuels and other unconventional liquids.

Natural gas is expected to replace oil wherever possible, with worldwide consumption projected to increase from 104 trillion cubic feet in 2005 to 158 trillion cubic feet in 2030. Much of the world's growing demand for natural gas is projected to be met by increased production from non-OECD nations.

Moreover, the consumption of coal, which in the past few years has increased sharply in its share of world energy use, is projected to increase significantly.

According to the report:

In the absence of national policies and/or binding international agreements that would limit or reduce greenhouse gas emissions, world coal consumption is projected to increase from 123 quadrillion Btu in 2005 to 202 quadrillion Btu in 2030, at an average annual rate of 2.0 percent.

Coal's share of world energy use has accounted for 24 percent of total world energy use in 2002 and 27 percent in 2005, largely as a result of rapid increases in use in China.

Among the highlights in the EIA's latest global energy outlook:

• Concerns over rising fossil fuel prices, energy security and greenhouse gas emissions support the development of new nuclear-generating capacity, although issues such as plant safety, radioactive waste disposal and the proliferation of nuclear weapons could slow the expansion of nuclear power in the future.

• Energy-related carbon dioxide emissions are projected to rise from 28.1 billion metric tons in 2005 to 42.3 billion metric tons in 2030 — an increase of 51 percent. Much of the increase in carbon dioxide emissions is expected to occur among the developing nations of the world, particularly in Asia, where there is strong economic growth and continued heavy reliance on fossil fuels.

• Sustained high prices for oil and natural gas encourage expanded use of renewable fuels, as government policies and incentives are expected to promote the development of renewable energy even when it cannot compete economically with fossil fuels.

Average world oil prices in every year since 2003 have been higher than the average for the previous year, and prices in 2007 were nearly double the 2003 prices in real terms.

Prices rose higher in the second quarter of this year, when in May they were already far exceeding the historical, inflation-adjusted record price for a barrel of oil, which was set in the early 1980s.