A solar-powered plane has landed in California, completing a risky three-day flight across the Pacific Ocean as part of its journey around the world.

Pilot Bertrand Piccard landed the Solar Impulse 2 in Mountain View, in the Silicon Valley south of San Francisco, on Sunday, following a 62-hour, non-stop solo flight without fuel.

The plane taxied into a huge tent erected on Moffett Federal Airfield where Piccard was greeted by the project's team.

Solar power - bright future?

The landing came several hours after Piccard performed a flyby over the Golden Gate Bridge as spectators watched the narrow aircraft with extra-wide wings from below.

"I crossed the bridge. I am officially in America," he declared as he took in spectacular views of San Francisco Bay.

Piccard and fellow Swiss pilot Andre Borschberg have been taking turns flying the plane on an around-the-world trip since taking off from Abu Dhabi, in the UAE, in March 2015.

It made stops in Oman, Myanmar, China, Japan and Hawaii.

The trans-Pacific leg was the riskiest part of the plane's global travels because of the lack of emergency landing sites.

"The idea here is not so much that solar planes can immediately replace jet planes powered by fossil fuel," said Al Jazeera’s Rob Reynolds, reporting from Mountain View.

"It is rather to give the pioneers of the technology inspiration for other uses of solar power."

Wider wings

The plane's ideal flight speed is about 28mph, though that can double during the day when the sun's rays are strongest. The carbon-fibre aircraft weighs more than 2,268kg, or about as much as a mid-size truck.

The plane's wings, which stretch wider than those of a Boeing 747, are equipped with 17,000 solar cells that power propellers and charge batteries. The plane runs on stored energy at night.

Solar Impulse 2 will make three more stops in the US before crossing the Atlantic Ocean to Europe or Northern Africa, according to the website documenting the journey.

The project, which began in 2002 and is estimated to cost more than $100m, is meant to highlight the importance of renewable energy and the spirit of innovation. Solar-powered air travel is not yet commercially practical, however, given the slow travel time, weather and weight constraints of the aircraft.

Source: Al Jazeera and agencies