Buzzing Hong Kong is better known for keeping lights on all night and the

Wind turbine

air conditioner running full blast, not saving energy. But engineers in the city have introduced an innovative wind energy technology than can help both rural and city residents protect the environment and cut down on energy costs - without having to spend a fortune on an expensive device. Claudia Blume reports.

A large wind turbine on a small outer island is one of Hong Kong's few sources of renewable energy. One of the reasons not more are being built is that the wind in the city is simply not strong enough, a problem it shares with many places worldwide.

Engineers at the University of Hong Kong and a private renewable energy company have developed a new micro wind turbine that can generate electricity even if wind speeds are as low as two meters per second.

Inventor Lucien Gambarota demonstrates how the micro wind-turbine can generate electricity

 Lucien Gambarota , the main inventor of the technology, says this is its advantage over conventional small wind turbines, which only work about 40 percent of the time because of low wind speed.

"We never stop this machine and they never stop because there is always one meter per second wind - 365 days, 24 hours a day, they keep working," said Gambarota. "They deliver different levels of energy because the wind changes but these turbines they keep moving, they keep spinning."

Gambarota says the small turbines are ideal for crowded cities such as Hong Kong because they can be installed on rooftops and balconies.

Their design is simple: plastic gearwheels, each about 25 centimeters in diameter, are linked to one another and turn, moved by the wind. Groups of gearwheels can be arranged in an array of shapes and sizes, ranging from about two up to thousands of square meters, depending on how much energy is needed and how much space is available. The energy generated by the turbines is stored in a battery, which then powers electrical appliances.

The wind turbine is easy to install and comparatively cheap. At the moment, a set of 20 gearwheels costs about $25. Gambarota says the price will go down once the turbines are being mass-produced, making them a good option for consumers who want to cut down on their energy costs.

"Let's say if you have good conditions, five, six meters [of wind] per second, if you are a family with one kid you need most probably three, four square meters of that then you can most probably cover at least 60, 70 percent of your [energy] needs."

The technology can also help power bigger buildings. Administrators at Hong Kong's Sea School, a secondary school offering basic seaman training, will install the new micro wind-turbines on its roof in April.

Gambarota says his biggest dream is to see his invention being used in developing countries. He says energy generated by micro wind turbines can be used to pump water, for example, saving women and girls from having to walk for miles to rivers and lakes to fetch it.