HOUSTON, Dec 9 (Reuters) - Global energy demand should rise some 35 percent through 2040 as the middle class expands in developing countries and supplies shift to lower-carbon fuels that may allow for lower emissions, Exxon Mobil Corp said on Tuesday in its annual outlook.
Exxon, the world's largest publicly traded oil company, said that without efficiency and technology gains overall energy demand would grow by 140 percent.
Though the global population is expected to rise to about 9 billion in 2040 from around 7 billion currently, energy demand and emissions are already starting to fall in developed countries thanks to greater efficiency, the company said.
That points to slower growth in emissions and an eventual leveling off overall.
"We expect global energy-related CO2 emissions will rise by about 25 percent from 2010 to 2030 and then decline approximately 5 percent to 2040," the company said.
While that 25 percent rise is considered significant, it would be about half the level of emissions growth seen from 1980 to 2010.
Exxon said alternative power sources should grow sharply, with solar capacity forecast to jump more than 20 times from 2010 to 2040, and wind power to expand almost five times. Nuclear is expected to grow about 90 percent, led by India and China.
Natural gas is forecast to supply 135 percent more electricity in 2040 than in 2010, and overtake coal as the largest source of electricity.
Coal's share of delivered electricity is forecast to drop to about 25 percent through 2040 from 40 percent as "most nations turn to cleaner, less carbon-intense fuels to improve air quality and curb greenhouse gas (GHG) emissions," Exxon said.
The massive onshore expansion in North America is also opening up vast amounts of inexpensive ethane from natural gas that is driving down costs for the chemicals and plastics industries.
Natural gas liquids are also expected to make up a growing share of global trade in hydrocarbons, with rising exports from North American to Asia.
Liquids other than conventional crude and condensate will account for about 45 percent of global liquids production, up from less than 25 percent in 2010, Exxon said.
"By 2025, we expect North America to be a significant natural gas exporter; by 2040, North America could even rival Asia Pacific," the company said. (Reporting by Terry Wade; Editing by Anna Driver and Jeffrey Benkoe)