Imagine the scenario: bulbs, washing machine and air-conditioner in your house could automatically switch to operate in an energy-saving manner at peak times of power use when electricity rates heighten.

Actually, it may come into reality soon. China is stepping up the "smart grid" construction across the country, as Premier Wen Jiabao put it in the work report to the top legislature last week.

Cai Guoxiong, deputy chief engineer of the China Electric Power Research Institute under the State Grid Corporation, said the smart grid has been piloted in big and medium cities since the State Grid kicked off the construction in May 2009.

The "smart grid" is an intelligent system capable of seamlessly integrating the alternative sources like solar and wind from power suppliers into the electricity network.

Also, consumers' home appliances could be centrally controlled by power companies via the grid to have access to power generated by renewable energy at lower prices.

A "unified strong and smart grid" system is to be built nationwide by 2020 to incorporate thermal power, hydroelectric power, nuclear power and other renewable ones, said Cai, also a member of the Chinese People's Political Consultative Conference (CPPCC) National Committee.

Xiao Liye, a smart grid expert in the Institute of Electrical Engineering under the Chinese Academy of Sciences, said larger scale smart grid construction will be included into China's new five-year development blueprint starting 2011.

China put the smart grid building on a strategic agenda to facilitate the use of renewable energy and reduce the country's excessive reliance on the high-polluting coal power generation, according to Cai.

Nearly two-thirds of energy supply in China has been fed by coal, making the country one of the biggest greenhouse gas emitters in the world.

According to a long-term outline for renewable energy development issued in 2007, China planned to increase the renewable energy proportion to 10 percent of the total energy use by 2010, and 15 percent by 2020.

It has displayed the government's resolution to develop the low-carbon economy after it pledged last year to reduce its carbon intensity by 40 to 45 percent by 2020 compared to 2005 levels, Xiao said.

China is now taking the lead in solar and hydropower generation and its wind power installed capacity ranks fourth in the world.

However, wind and solar energy is usually subject to weather changes and could not produce uninterrupted supplies, and so it is hard to smoothly transmit the power via the traditional grid that carries only stable thermal power supply.

Nearly one-third of the wind power generated in the country has been rendered redundant owing to the transmission bottleneck, according to experts.

Li Wuwei, CPPCC National Committee vice chairman, said, "What we need is a grid network to integrate the thermal and renewable energy supplies."

"A safe, stable and efficient grid that could massively transmit the renewable energy power must prove to be a giant technological revolution in energy industry," Xiao said.

The Standing Committee of the National People's Congress, China's top legislature, approved the amendment to Renewable Energy Law in December 2009, urging efforts to develop the advanced grid in a bid to transmit more renewable energy.

"China gives top priority to the smart grid development since the renewable energy cannot be utilized in large scale without smooth grid transmission," Xiao said.

Also, households could be connected to the smart grid by optical cable that combines the Internet and telephone access, Cai said.

"The consumers can check their power use and electric bill online and even manage the home appliances in remote distance."