If you’re looking for hope and inspiration in what has been a testing year for many, then look no further than Solar Impulse 2.

This morning the solar-powered plane touched down in Abu Dhabi, United Arab Emirates, at 4:05am local time, bringing to an end a momentous journey around the world using nothing but the Sun’s rays to keep its four propellers turning.

Packed with 17,000 solar cells on a body as light as a car but as wide as a jumbo jet, Solar Impulse has been a pioneering example of what is possible with solar power. It’s not going to lead to a re-imagining of the aviation industry in the way that, say, Tesla has done with electric cars for the automotive industry. But it should prove as inspiration that renewable energy can be a beacon of hope in this day and age.

The single-seater plane was the brainchild of Swiss pilots Bertrand Piccard and André Borschberg, who took it in turns to fly the plane on its 17 legs around the world. The journey began in Abu Dhabi on March 9, 2015, with its journey of 43,041 kilometers (26,744 miles) taking it across Asia, the Pacific Ocean, the US, the Atlantic Ocean, and the Middle East. This final leg, lasting two days, was from Cairo, Egypt, to Abu Dhabi.

^{Borschberg (left) and Piccard, pictured shortly after the landing. Solar Impulse}

“I’m going to give a hug to each member of the team [after I land],” Piccard, who flew this leg of the journey, told IFLScience while he was still in the air. “And to my family, who supported me during all these years and encouraged me all the time.

“[I want] to thank them for the incredible devotion and commitment that they have shown through all these years.”

Piccard had dreamt of fulfilling the goal of flying around the world on solar power since he flew around the world non-stop in a balloon in 1999. That dream edged towards reality with Solar Impulse 1 in 2009, a prototype that proved the technology was possible.

Then, in 2014, Solar Impulse 2 was completed. And, for the last 16 months, which included a 9-month hiatus due to battery issues, the pilots have been taking their message of clean energy from country to country. Whether Solar Impulse will make a dent in global adoption of renewable energy remains to be seen, but the message is clear: renewable energy is here, it is clean, and it can even fly a plane around the planet.

Flying the plane itself was no mean feat. To save on weight it was stripped of many of the amenities one might expect, meaning the pilots had to go without many comforts such as heating or air conditioning. Going to the toilet consisted of using a rather unsavory hole in the pilot’s seat, while sleep consisted of short 20-minute catnaps – even on the longest flights, which lasted several days.

To keep its power running, the plane flew above the clouds to collect sunlight during the day, before dipping down lower at night to save its batteries. And owing to being completely solar powered, it packed a modest top speed of just 75 km/h (47 mph).

But the mission, aside from promoting renewable energy, has broken numerous records along the way: 19 according to the Solar Impulse team. This includes Borschberg’s five-day crossing of the Pacific Ocean from Japan to Hawaii in June 2015, the longest solo airplane flight ever attempted. And Piccard became the first person to cross the Atlantic Ocean in a solar airplane when he flew from New York to Seville in June this year.

^{Piccard snapped this view out of the window on his way to Abu Dhabi. Solar Impulse}

“This is not only a first in the history of aviation; it’s before all a first in the history of energy,” said Piccard after exiting the cockpit this morning. “The same clean technologies used on Solar Impulse could be implemented on the ground in our daily life to divide by two the CO2 emissions in a profitable way.”

“More than a demonstration, it’s the confirmation that these technologies are truly dependable and reliable,” added Borschberg.

In a world where Britain has voted to leave the European Union (to the detriment of science) and Donald Trump continues a terrifying march towards the White House (to the detriment of pretty much everyone), perhaps Solar Impulse is the beacon of hope we needed – although not necessarily deserved.