World nuclear power generation could fall by up to 15 per cent by 2035 following the Fukushima disaster.
The IEA makes the predictions in a draft copy of their 2011 World Energy Outlook report due to be released next week, adding that power demand may rise by 3.1 per cent a year.
Many countries have put their nuclear power policies on hold or under review while some, including Germany and Switzerland, have opted out of the technology entirely.
The report outlines a "Low Nuclear Case" which assesses possible implications for global energy balances of a much smaller role for nuclear power.
"In the Low Nuclear Case, the total amount of nuclear power capacity falls from 393 gigawatt (GW) at the start of 2011 to 339 GW in 2035, compared with an increase to 638 GW in the New Policies Scenario," the report said, a drop of around 15 per cent.
The report said its Low Nuclear Case was not a forecast, but "is intended to illustrate what a pessimistic view of the prospects for the nuclear power industry might entail."
"The share of nuclear power in total generation drops from 13 per cent today to just seven per cent in 2035, with implications for energy security, fuel-mix diversity, spending on energy imports and energy-related CO2 emissions."
The report said that Fukushima had "shaken the country's energy sector" and that "the prospects for nuclear power are now much more uncertain than before the Fukushima nuclear accident" and that it had "greatly increased the uncertainty about the future role of nuclear power in meeting the world's energy needs."
The IEA report said that the drops in nuclear generation caused a rise in oil- and gas-fired power generation.
"The incremental demand for oil in Japan's power sector in 2011 is estimated between 150 and 200 thousand barrels per day while demand for LNG (liquefied natural gas) is expected to rise by 11 billion cubic metres (bcm)," the report said.
This is about 0.2 per cent of global oil supplies and 0.4 per cent of natural gas supplies, according to the report.
Global energy prices dropped back shortly after the Fukushima-induced rise, the report said, adding that it expected natural gas prices to drop in the longer-term.
"Our natural gas price assumptions have been revised downwards because of improved prospects for the commercial production of unconventional gas resources," the IEA said.
The report's main scenario is the New Policies Scenario, in which natural gas prices are expected to reach $12 per million British thermal units (MBtu) in Europe, $14 per MBtu in the Pacific, and $9 per MBtu in North America by 2035.
This compares with 13.3 MBtu, 15.3 MBtu and $10.4 MBtu respectively in the IEA's previous price outlook for 2035.
In the same scenario, the report said it expected world electricity demand to rise from 17,200 terawatt-hours (TWh) in 2009 to almost 31,500 TWh in 2035, at an annual growth rate of 3.1 percent.
In its other two scenarios, the Current Policies Scenario and the 450 Scenario, annual growth rates for global electricity demand is 3.7 and 2.3 percent respectively.
The 450 Scenario sets out an energy pathway consistent with the international policy goal of limiting the temperature increase to two degrees Celsius, according to the draft.
The report said that total investment into the power sector between 2011 and 2035 would be $16.8 trillion.
"Renewable energy technologies, led by hydropower and wind, account for half of this additional capacity and 60 per cent of the investment in power generation," the report said.
"The resulting growth in output from renewables is equivalent to 46 per cent of the total electricity generation between 2009 and 2035."
The report said it expected non-hydro renewables to generate 16 per cent of global electricity in 2035, up from three per cent in 2009.
Natural gas power generation was expected to remain constant around 22 per cent.
The IEA also said it expected steam coal prices to rise to $110 a tonne (in year-2010 dollar value) by 2035, up from an average of $99 a tonne in 2010.
The report said that while it expected coal's share in global power generation to drop by 8 percent to 33 percent, it would remain the largest source of electricity.
"CO2 emissions in the power sector increase by over one-fifth between 2009 and 2035, growing more slowly than demand as a result of increased use of low-carbon energy sources and improved plant efficiency."
Prices for carbon allowances within the European Union were expected to rise to $31 a tonne by 2020, to $41 in 2030, and to $46 per tonne by 2035, the report said.
Under the New Policies Scenario, Australian and New Zealand carbon prices would rise from $30 a tonne in 2020, to $42 in 2030, and to $48 a tonne in 2035, according to the draft.
Korean carbon prices would rise from $18 a tonne in 2020 to $36 in 2030, and to $45 in 2035, while Chinese prices would rise from $10, to $23, and to $30 a tonne during that time.
Overall, the report said that energy import bills would rise in line with higher import requirements.
The IEA's full WEO outlook report is due to be published next week.