The growth outpaced the 5.7-percent expansion recorded in July. Daily power generation reached 20.66 billion kWh last month, a historic high.
For the first eight months, power generation grew by 7.7 percent, 1.2 percentage points higher than the same period last year.
In August, thermal and hydropower output climbed 6 percent and 11.5 percent year on year, respectively, up by 1.7 percentage points and 5.5 percentage points from July.
As for new energy, nuclear and solar power generation went up 16.9 percent and 12.2 percent year on year, respectively.
Due to typhoons and heavy rainfall in the summer, wind power output only increased by 0.6 percent year on year in August, 24.1 percentage points lower than the July expansion, according to the NBS.