The Solar Impulse 2 plane, about to embark on the most daunting leg of its epic round-the-world journey, is taking renewable energy and clean technology to new heights, says pilot Bertrand Piccard.

“I want to show people that this is something exciting,” he told FoxNews.com, during a phone interview. “It’s an opportunity for our society, our industry, and our economy – it’s not just for the environment.”

Piccard and his fellow Swiss pilot Andre Borschberg are taking turns flying the solar-powered aircraft on its five-month journey around the globe. Solar Impulse 2 set off from Abu Dhabi in March, and has stopped in Oman, India, and Myanmar en route to its latest stop in Nanjing, China. Borschberg will fly the next leg of the journey, a 5,079-mile, five-day, flight to Hawaii, as soon as weather conditions permit.

Solar Impulse 2 is expected to fly between 30 mph and 60 mph during its journey.

The lightweight plane, a larger version of a single-seat prototype that first flew five years ago, is made of carbon fiber and has 17,248 solar cells built into the wings that supply the plane with renewable energy, via four motors. The solar cells recharge four lithium polymer batteries, which provide power for night flying.

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    “The engine on Solar Impulse is 97 percent efficiency – if you have a gasoline engine, it’s 27 percent efficiency,” said Piccard.

    The plane has a 236-foot wingspan, larger than that of the Boeing 747, but, thanks to the lightweight carbon fiber, weighs about as much as a car at around 5,070 pounds.

    “We want to try to encourage people that renewable energy and clean technology can achieve the impossible,” said Piccard. “Theoretically, we could fly forever [in Solar Impulse 2].” The flight, he added, could spark increased interest in technologies such as LED lights and electric cars, as well as lightweight vehicles.

    The latest leg of the journey, however, is the biggest challenge that the Solar Impulse 2 team has faced so far. While none of the previous legs were more than 20 hours, the estimated flight time to Hawaii, across a vast expanse of ocean, is 120 hours.

    The Solar Impulse 2 team is now carefully simulating its flight and monitoring weather conditions. Piccard explained that excessive cloud over the Pacific could prevent the plane from reaching Hawaii.

    “We need good weather and good flying conditions during five days,” he said. “We can identify a weather window three days in advance - we’re waiting, programming all the flights, simulating all the flights.”

    Piccard, however, is already looking forward to flying the second Pacific leg, from Hawaii to Phoenix, a journey of 3,106 miles, which is expected to take between three and four days. “To see the coast of the U.S. after passing the second leg of the Pacific, it will be fantastic,” he said.

    After Phoenix, the plane is slated to stop in New York, possibly around mid-June, before flying over the Atlantic Ocean. It will then stop in southern Europe or North Africa, depending on weather conditions.

    The Associated Press contributed to this report.