China's state planner is moving to refine the pricing mechanisms for services essential to stabilising power supply in markets increasingly dependent on wind and solar power, in a fresh step toward creating a national electricity market by 2030.

The National Development and Reform Council (NDRC) said in a notice on Thursday that it would "further promote the development of an ancillary services market" that would be "suited to the development needs of a new energy system."

NDRC, in the notice, said it would focus on optimising pricing mechanisms for standby capacity, frequency modulation and so called peak shaving - which are ancillary services essential to maintaining reliable electricity supply.

The peak shaving market allows power companies to buy power from quick-ramping sources such as energy storage and flexible coal plants, to help them meet spikes in demand.

Frequency regulation helps maintain normal frequency on the grid, a function that can be performed by battery storage systems and generators such as coal- and gas-fired plants.

The ancillary services rule is among a series of basic documents setting out the rules for a national electricity market by 2025, with the market's start targeted for 2030.

(Reporting by Colleen Howe; Editing by Sonali Paul)