Solar Impulse 2 (SI2) is seen in the darkness as it arrives at Al Bateen Executive Airport in Abu Dhabi, the United Arab Emirates (UAE), on July 26, 2016. The fully-solar energy powered plane arrived in Abu Dhabi on Tuesday and completed its global tour. The plane took off for its round-the-world journey in March 2015 from Abu Dhabi, to raise awareness on the viability of renewable energy. (Xinhua/Li Zhen)

Solar Impulse 2 (SI2) arrives at Al Bateen Executive Airport in Abu Dhabi, the United Arab Emirates (UAE), on July 26, 2016. The fully-solar energy powered plane arrived in Abu Dhabi on Tuesday and completed its global tour. The plane took off for its round-the-world journey in March 2015 from Abu Dhabi, to raise awareness on the viability of renewable energy. (Xinhua/Li Zhen)

Journalists take photos and videos as the Solar Impulse 2 (SI2) arrives at Al Bateen Executive Airport in Abu Dhabi, the United Arab Emirates (UAE), on July 26, 2016. The fully-solar energy powered plane arrived in Abu Dhabi on Tuesday and completed its global tour. The plane took off for its round-the-world journey in March 2015 from Abu Dhabi, to raise awareness on the viability of renewable energy. (Xinhua/Li Zhen)

Solar Impulse 2 (SI2) arrives at Al Bateen Executive Airport in Abu Dhabi, the United Arab Emirates (UAE), on July 26, 2016. The fully-solar energy powered plane arrived in Abu Dhabi on Tuesday and completed its global tour. The plane took off for its round-the-world journey in March 2015 from Abu Dhabi, to raise awareness on the viability of renewable energy. (Xinhua/Li Zhen)

ABU DHABI, July 26, 2016 (Xinhua) -- Solar Impulse 2 (SI2) arrives at Al Bateen Executive Airport in Abu Dhabi, the United Arab Emirates (UAE), on July 26, 2016. The fully-solar energy powered plane arrived in Abu Dhabi on Tuesday and completed its global tour. The plane took off for its round-the-world journey in March 2015 from Abu Dhabi, to raise awareness on the viability of renewable energy. (Xinhua/Li Zhen)