OPEC kept its forecast for growth in world oil demand unchanged for 2012 and 2013, as the organization's ministers gathered in Vienna for a meeting on output amid economic sanctions on Iran.
World oil demand this year was expected to reach 88.80 mbpd, up from 88.04 mbpd in 2011, the group said in its monthly report.
Next year, global demand is set to grow to 89.57 mbpd, OPEC forecast.
The report comes a day before OPEC ministers of the 12-nation group meet in Vienna to decide on its oil production ceiling.
"Japanese oil use in power plants increased from 7.5 percent of total energy use to 19.7 percent. This denotes growth of 300,000 bpd for the country in 2012 and made up 40 percent of annual world oil demand growth," the organization said.
For 2013, OPEC was more optimistic, citing an improving economy in the US and a potential return to growth in the euro zone.