For 200 years, Dezhou in east China's Shandong Province has been famous for braised chicken cooked in soy sauce with special spices.

But today the city of 5 million people has shifted its speciality from cuisine to solar energy.

Here a State-level pilot energy-efficient building project has been under construction since January. The first four of 12 apartment buildings, each either 12 or 15 floors, will be handed over to buyers in June next year, said Cheng Muwen, deputy director of the city's development and reform commission.

The compound, which will eventually contain 1,900 households, will have solar-powered heating and air conditioning systems installed in the roofs of the apartment blocks.

Power supply for lighting in the compound's public areas and gardens will be produced by photovoltaic devices.

"The Dezhou City government requires all real estate projects to incorporate energy-saving measures, or they will not be approved," Cheng said.

In the past decade, Dezhou has gradually gained a reputation as a solar-powered city. Street lamps and lighting in the parks are equipped with small-scale solar panels, and solar-powered water heaters reflect the sun on apartment building roofs. In addition, the city is powering traffic lights using the sun's rays.

"About 80 percent of residential buildings in our city are equipped with solar water heaters," said Xu Jie, director of the energy saving office of the city government.

The company's power

Dezhou, positioned between latitudes 36.24 and 38 degrees north, does not receive any more sunshine than its counterparts.

Major support for the city's energy programs comes from approximately 100 private solar-power enterprises in the city. They contribute to 16 percent of China's solar-powered water heating and have an annual revenue of 5 billion yuan.

Himin Group, the largest, which claims it sells 3 million square meters of solar-powered vacuum tubes a year, has made its own office building an eco-friendly model of solar energy applications.

Green plants grow on the roof, solar panels hang on outside walls, and windows are equipped with highly efficient heat-absorbing glass and blinds that automatically open or close according to temperature changes inside.

"There is no traditional air conditioning system but it is still very cool inside," said Han Changming, a Himin employee who has an office in the building.

Cold water runs through pipes in the ceiling, fueled by solar power. In the winter, warm sunshine outside will be turned into heating inside via the same pipes.

"The air from the ventilation system is gentle and comfortable like natural breezes," Han said.

Beside the office building -- with about 800 employees -- there is a five-star hotel with 500 rooms powered by the same energy-efficient arrangements.

The hotel, which started trial operations Thursday, will be the main venue of the fourth World Solar Cities Congress in September next year.

These are part of the Himin Group's ambitious plan to build a "Solar Valley" in an 333 hectare-area in Dezhou's suburbs.

"We are aiming to build a world-class research and manufacturing center of renewable energy as well as a center that promotes energy-saving ideas," said Huang Ming, the company's president.