BEIJING – China plans to build a safe and environmentally friendly smart-grid system by 2020 as it promotes the spread of clean energy.

The nation will build long-distance transmission networks and active power distribution networks to fully use hydro power, wind and solar, according to a statement from the National Development and Reform Commission.

Grid constraints threaten to temper China’s rush to develop renewable energy supplies. Already, some of the nation’s wind capacity has been idled because of issues with the grid. There’s also the matter of being able to get power from where it’s produced to where it’s needed most.

To expand capabilities, China will accelerate the construction of micro grids and promote the development of energy sources that don’t need transmission lines, including distributed solar projects and power from micro-gas generators, the NDRC said.

The focus on smart grids comes as the world’s biggest carbon emitter spends more on grid development to meet power demand. China’s biggest power distributor, China State Grid Corp., spent about 400 billion yuan ($64 billion) last year on its electricity networks.

China’s burgeoning clean energy resources are also behind the demand for a smarter grid system. The nation pledged by 2030 to get 20 percent of its energy from renewables and nuclear power, almost double the current share.

The nation plans to improve its “flexible” control capability over transmission and distribution networks to ensure stable power supply given the higher share of clean energy, according to the statement.

The grid system will also meet demand created from broader use of electric vehicles and energy storage, the agency said.