The Solar Impulse Second, the world's largest solar-powered plane, will make two stopovers in China during a round-the-world flight in 2015, its builders said on Monday.

The second-generation model can fly day-and-night without fuel for five consecutive days and will stop in Nanjing, capital of Jiangsu province, and Chongqing municipality.

The exact dates for the two stopovers will be decided according to weather conditions, but the flight will start in March taking off and returning from Abu Dhabi, capital of the United Arab Emirates.

The Swiss-made, long-range aircraft project is being led by Swiss psychiatrist and pilot Bertrand Piccard, who said China is expected to be its fourth stopover on the journey, after India and Myanmar.

"If you look at how much effort the Chinese government is making to increase the use of renewable energy to optimize the energy mix, you will know that these stopovers are important for us to promote advanced clean technologies," said Piccard.

He said he is already in talks with several Chinese companies with a view to cooperation of the project, and passing on the technology used on the aircraft.

Chongqing has been chosen as a stopover as it currently plays an important role in the government's campaign of "going west", said Piccard. But both cities are ideal landing sites as they have perfect local weather conditions for flying－not too windy nor too cloudy.

The aircraft is powered entirely by solar panels and batteries and has a wingspan of 72 meters, which is longer than a Boeing 747 commercial jet. The wings themselves are covered with 17,248 solar cells that power the plane's various systems. It weighs about as much as a family car at 2,300 kilograms.

Its cockpit is large enough, say the designers, for a pilot to live in-flight for a week; but without any heating or pressurization, flying the craft is still considered a significant endurance test.

"This upgraded plane shows just how far solar power has come and how far this clean energy technology will go in the near future," said the Solar Impulse's co-pilot and co-founder Andre Borschberg.

After stopping in China, the ultra-lightweight plane will fly over the Pacific Ocean before crossing the United States, the Atlantic Ocean, Southern Europe and North Africa before returning to Abu Dhabi.

Landings will be made every few days to change pilots and hold public events for governments, schools and universities.Hangzhou Bay zone revitalizing the region