By BLOOMBERG

BEIJING • China set three year targets for allowing more wind and solar power onto the power grid after the rapid addition of panels and windmills forced some electricity distributors to partly block that energy from flowing into their systems.

The curtailment rate for wind power should be held to less than 10% next year and to about 5% by 2020, from an estimated 12% this year, according to a document posted on the Sichuan Energy Regulatory Office website last Friday. The rate for solar should be held below 5% from 2018 to 2020.

The world’s biggest clean energy investor has had to slow the introduction of renewable power because some grids were not capable of handling big increases.

China idled about 2.9% of the solar power capacity in the first nine months of this year, compared to 5.6% a year earlier. The curtailment rate for wind was 7.7% during the period.

“The re-emphasis of the target as well as more detailed guidance to each province should be positive to the market sentiment,” Nelson Lee, a Hong Kong based analyst from ICBC International Research Ltd, wrote in a note. “Wind operators are set to benefit from the policy as they have a relatively high share of wind farm mix in provinces with new wind curtailment targets”, such as Xinjiang, Gansu and Heilongjiang.

China will further reduce development costs of renewable energy and set plans to gradually cut prices for clean power.