The Swiss-made solar-powered plane Solar Impulse 2 departed from Nanjing, Jiangsu province, on Sunday morning to fly across the Pacific, the toughest sector in its round-the-world trip.

The plane's departure from China for Hawaii at 2:40 am came more than a month after it landed in Nanjing at night on April 21.

The plane's original departure from Nanjing planned for May 5 was delayed as the two pilots waited for the right weather conditions.

The journey from Nanjing to Hawaii is expected to take six days and six nights, with Andre Borschberg, 62, at the controls.

While he crosses the ocean, Borschberg will only be able to sleep for 20 minutes at a time, the maximum amount of time the plane can navigate automatically.

Bertrand Piccard, the other pilot, said during his stay in Nanjing that the flight across the Pacific requires a period of clear weather, and forecasts predicted typhoons over the ocean for the past two weeks.

Powered by more than 17,000 solar cells installed on its wing, Solar Impulse 2 is circumnavigating the globe to promote green energy.

The plane has featured in a number of events during its stay in China to promote new energy and materials.

It has 12 scheduled stops on its around-the-world mission.

After reaching Hawaii, the plane will continue across the Pacific and the United States before stopping in Africa and finally reaching Abu Dhabi in the United Arab Emirates from where it first took off on March 9.

"I feel privileged to be able to try this flight. ... We have the right equipment and team to help us navigate. So I feel really confident of making it to Hawaii," said Borschberg.

(China Daily 06/01/2015 page3)