Buildings account for a third of China's total energy use, and energy-efficiency goes far beyond just installing solar water heaters.

Huang envisions the Utopia Garden project being replicated in Hangzhou, Qingdao and Wuhan. However, he says, solar water heater manufacture will always be his main business despite the property business expansion.

Himin's own offices are a model of solar technology. The building, already a landmark in Dezhou, is covered by solar panels on the outside and its windows are equipped with highly efficient heat-absorbing glass.

Steve Sawyer, secretary general of the Global Wind Energy Council, said: "The level of enthusiasm and almost messianic zeal with which he (Huang) is pursuing the goal is very unusual."

Huang, a fluent English speaker, met Sawyer in Vienna at a global conference.

It has reported that most of his employees fear him as he pushes relentlessly for higher standards. In the company's early days, Huang put a card on each desk, urging his employees "to learn the persistence of Japanese and prudent manner of the Germans," according to a report in China New Time magazine.

Chinese media have given Huang many nicknames -- solar madman, ambassador of renewable energies, sun king and solar patriarch -- for his contribution and perseverance in promoting solar energy use.

However, few are aware that his energy expertise began in the oil industry more than two decades ago.

After graduating from the China University of Petroleum in 1982, Huang became a drilling and research engineer in an institute in Dezhou. His visions of a green future were nurtured by his teacher's remark that "the world's oil reserves will run out in 50 years."

The birth of his daughter in 1986 changed his destiny and led to his decision to shift to clean energy. "She is so adorable and I feared she would have no blue skies and white clouds to see when she grew up."

Huang made his first solar-powered water heater in 1988, inspired by a book titled Solar Engineering of Thermal Processes written by William Beckman. Seven years later, Huang set up Himin, whose Chinese pronunciation is also "Huang Ming".

Sales were initially tough as solar water heaters were new to Chinese and the public had little understanding or awareness of environmental protection and energy-saving.

With staff in a mini-bus painted green, Huang drove through major cities to promote his product in 1997. The bus, emblazoned with the slogan "You should use a solar water heater to save the blue sky and white clouds for the children, even you don't choose Himin," covered more than 80 million kilometers.

Himin has expanded rapidly since the Chinese government stepped up efforts to promote energy efficiency and cut emissions. In 2008, the company sold 3 million square meters of solar panels, exceeding 10 Bird's Nest Olympic stadiums in area.