URUMQI, Jan. 29 (Xinhua) -- New energy power generation saw double digit growth last year in northwest China's Xinjiang Uygur Autonomous Region amid efforts to reduce coal consumption to improve the energy mix.

Wind and solar power generation rose 15.2 percent and 13.6 percent to 36 billion kwh and 11.7 billion kwh respectively, according to the regional development and reform commission.

It said 22.9 percent of installed wind power generating capacity and 15.5 percent of the solar power generating capacity in Xinjiang were left idle last year, respectively 6.9 percentage points and 6.1 percentage points lower than a year ago.

The idle capacity was a result of higher costs, rapid capacity increases, poor grid connections and the grid's preference for more predictable coal-generated power.

The lower idle capacity came as local authorities encouraged more local consumption and transmitted more to regions in the country's bustling east.

Despite the efforts, the idle rates in Xinjiang were still one of the highest in the country.

According to the State Grid Xinjiang Electric Power Co. Ltd., Xinjiang has a total installed power generating capacity of 85.5 GW, with wind and solar energy contributing 28.7 GW.

To cut greenhouse gas emissions and tackle air pollution, China has been trying to use more renewable energy to reduce its heavy reliance on polluting coal.