Huang started the Utopia Garden project despite skepticism that a solar water heater maker could be a developer. "A major factor pushing me into the property market was the frequent refusal by developers to install solar water heaters on their buildings."

Property developers don't bother to add value to homes by installing energy-efficient facilities because apartments are sold before construction, Huang says.

"I'm saving the country in a devious way," he jokes.

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 50years."