Solar Impulse achieves solar energy first

Solar Impulse’s circumnavigation of the globe under solar power paves the way for decarbonisation of air transport.
Published: Wed 27 Jul 2016

It’s been a long journey extending over 16 months, but the completion of Solar Impulse 2’s 40,000 km circumnavigation of the globe on July 26 has marked a significant first – the first such flight of an aircraft completed on solar power alone.

The venture was the vision of Swiss pioneers Bertrand Piccard, a medical doctor specialized in psychiatry, explorer and aeronaut, and André Borschberg, an engineer, pilot and graduate in management science. And it begs comparison to that of the Wright brothers who made the first powered flight in their Kitty Hawk back in 1903.

The Wright brothers’ pioneering efforts have, as we know, given way to a global industry in which some 6,000 or so planes are in the air at any one time. Piccard and Borschberg’s ‘Kitty Hawk moment’ opens the way for the introduction of solar power and decarbonization of this mode of travel. [Engerati-The First Solar Powered Round-the-World Flight]

Solar Impulse facts and figures

The Solar Impulse venture has been a long time in the making, having its origins in 1999, following a round the word balloon flight by Piccard.

With a 72m wingspan - wider than a Boeing 747 Jumbo - but the weight of a family car, the plane presented a design challenge that was thought impossible to achieve. Indeed, in the end Solar Impulse 2 turned out to be “a flying laboratory full of clean energy technologies,” according to the project website. Built out of ultralight materials, it includes 17,248 solar panels for power along with four 38.5kWh batteries for storage for night-time flying to power four 13.5kW energy efficient electric motors.  

Indeed, learning proved critical. The batteries, damaged by overheating in the leg from Japan to Hawaii due to be being packed in too much insulation, led to the most significant delay – almost 9 months in length – of the whole journey. [Engerati-KEPCO Leads Way With Battery Storage For Frequency Regulation]

The journey was eventually completed in 17 legs covering a cumulative distance of 43,041km in a time of 558h06m with 11,655kWh of solar energy. That’s an average speed of 77km/h – not exactly fast by air travel standards but then nor were the Wright brothers’ first flights of a few tens of metres comparable with the more than 15,000km range of the modern jetliner.

“Flying one leg with a completely new type of airplane is difficult enough, but flying around the world is a real challenge. More than a demonstration, it’s the confirmation that these technologies are truly dependable and reliable,” said Borschberg on completion of the flight in Abu Dhabi. “There is so much potential for the aeronautical world: while one hundred percent solar powered airplanes might take longer to materialize, electric airplanes will develop in the near future because of their tremendous advantages such as energy efficiency.”

“This is not only a first in the history of aviation; it’s before all a first in the history of energy. I’m sure that within 10 years we’ll see electric airplanes transporting 50 passengers on short to medium haul flights,” added Piccard. “But it’s not enough. 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.”

Promoting clean energy technologies

Looking forward, Piccard and Borschberg will continue to actively promote the use of modern clean technologies as a way to improve the quality of life on Earth, according to a statement.

During leg 15 across the Atlantic Ocean, the two pioneers announced the International Committee for Clean Technologies (ICCT) to build on the #futureisclean initiative, which had been launched ahead of COP21, in order to regroup the main global actors in the field of clean technologies to bring independent and credible guidance on energy policy to governments and corporations.

"We have flown 40,000km without fuel but there is still a lot to be done to encourage a worldwide implementation of clean technologies and to motivate everyone to reduce their dependence on fossil fuels in their daily lives, hence the creation of the ICCT,” said Piccard.

They will also carry on the work initiated by the engineering team on unmanned and high endurance electric aircraft, which could fly at high altitude for months, offering services that could provide exponential added value and complement the work being done by satellites today in a flexible and sustainable way.

“Solar Impulse is very well positioned to contribute to the next generations of manned or unmanned electric aircrafts. By capitalizing on the engineering skills and expertise gained over the past decade, we will continue to work to encourage concrete innovations and disruptive solutions,” commented Borschberg.