That's bigger than the reduction expected by the International Energy Agency, which last week forecast a decrease of about 500, 000 barrels a day, or 0.6 percent, this year.

On a per capita basis, Chinese energy demand is still around a third of the average of industrialized nations, according to IEA data.

To help solve the riddle, NASA and the U. S. Department of Energy will soon announce the flagship of the Joint Dark Energy Mission (JDEM), the first program specifically designed to study dark energy.