In this Wednesday, July 13, 2016, handout image provided by Solar Impulse, the Solar Impulse 2 flying over the pyramids, Egypt Cairo. The experimental solar-powered airplane has arrived in Egypt as part of its global voyage. (Photo by Jean Revillard, Rezo via the AP Photo)

A view of balloon depicting an Alebrije, is seen at the 14th Solar Balloon Festival in Envidago December 31, 2014. According to the festival organizers, the Alebrije balloon will be largest replica of an Alebrije. This year features a theme on Mexican history and culture, organizers added. (Photo by Fredy Builes/Reuters)

A partial Solar eclipse is seen just after sunrise over the Queens borough of New York across the East River on November 3, 2013 in New York. (Photo by Stan Honda/AFP Photo)

Rooftops of solar powered houses are pictured in Ota, 80 km northwest of Tokyo in this October 28, 2008 file photo. One by one, Japan is turning off the lights at the giant oil-fired power plants that propelled it to the ranks of the world's top industrialised nations. With nuclear power in the doldrums after the Fukushima disaster, it's solar energy that is becoming the alternative. Solar power is set to become profitable in Japan as early as this quarter, according to the Japan Renewable Energy Foundation (JREF), freeing it from the need for government subsidies and making it the last of the G7 economies where the technology has become economically viable. (Photo by Yuriko Nakao/Reuters)

A pedestrian battles against gale force winds in Adelaide Street West next to the promenade in Blackpool on December 28, 2011 in Blackpool, England. (Photo by Christopher Furlong/Getty Images)

The first solar-powered station designed to look like a tree provides users with a free Wi-Fi spot charging station, seating and cool drinking water.

Emperor penguins gathered together to keep their chicks warm in these pictures. Marine scientist Frederique Oliver snapped the protective parents in Antarctica as they huddled against the huge winds.The adorable birds have to battle temperatures on -20 degrees Celsius as well as winds of up to 40 knots on the ice. (Photo by Frederique Oliver/Caters News)

This April 9, 2016 photo provided by Bertrand Piccard via Global Newsroom shows Piccard taking a selfie on board Solar Impulse 2 during a test flight over the Pacific Ocean. The solar-powered airplane on an around-the-world journey had traveled 80 percent of the way from Hawaii to California by Saturday, April 23. The aircraft's destination on this leg of the journey is Mountain View, Calif., at the southern end of San Francisco Bay. (Photo by Bertrand Piccard/Global Newsroom via AP Photo)