Swiss aviators Bertrand Piccard and André Borschberg have realized their dream. Early Tuesday morning the two successfully finished their round-the-world journey, becoming the first airplane to circle the world using only solar power. The eyes of children and adults alike light up at the news, it really is a reason to celebrate. Nobody can deny the adventurers' success.

But, after the celebration, one needs to sober up. It is simply not fair to group Solar Impulse 2 with early aviation pioneers such as the Wright Brothers or Charles Lindbergh. They were a symbol of a historical period of highly dynamic industrial development.

From biplane to jumbo jet

Shortly after the turn of the century, the Wright Brothers were the first to build primitive biplanes. Thus, laying the cornerstone for the rapid development of the aviation industry. Another milestone came in 1927, when American Charles Lindbergh crossed the Atlantic in a motorized plane.

The production of modern military, postal and passenger airplanes took off drastically after the developments of the 1920s. Following World War II, the first regular passenger flights took off, crossing the worlds' oceans. And in 1969, the year of the moon landing, the first jumbo jet took to the skies.

A huge electro-powered motor-glider

Solar technology, in contrast, does not offer solutions to the transport-problems of tomorrow. Solar Impulse 2 is no more, and no less, than a glorified motor-glider and in essence remains a piece of sports equipment - despite all the scientific ambitions of its developers and the interesting concepts and discoveries, like in the field of lightweight construction.

The airplane was only able to fly, because it was armed with all kinds of complex modern technologies.

The adventurers were able to rely on a large team of ground staff, as well as satellite communications, weather data, navigational technology and an array of computer systems. Similar to competitive cyclists who have several cars laden with equipment following behind them, Piccard and Borschberg were able to rely on a huge chain of logistics.

Ground staff flew ahead of the aircraft, of course with regular jet planes. Cargo planes shipped new batteries after the originals overheated on the journey from Japan to Hawaii.

Battery technology remains volatile

If there is anything Solar Impulse 2 showed, it is how volatile battery technology still is. Rechargeable batteries are simply too heavy, too delicate and not powerful enough for use where great distances have to be bridged, weight is of the essence and huge power peaks are required.

Even the latest generation of batteries is not robust enough for intensive use over many years. Regular mobile phone batteries are usually exhausted after less than seven years of moderate use. And, when playing Pokemon Go, most batteries will die in no time. How then is airborne electro-mobility supposed to function, with commuter aircraft being turned around at gate several times a day on short distance flights? And which airline company is supposed to shoulder the risk if a plane goes out of service?

Even the latest successes in developing better and more robust batteries should not blind us from one simple truth: the most efficient form of storing and transporting energy remains fuel, be it liquid or gas. As far as robustness, endurance and capacity is concerned, nothing can compete with combustion engines.

In future, electro-mobility will only have a place where distances are very short, like in the case of electric bicycles, or where it is possible to bring the electric power directly to the vehicle - with an overhead line, like in the case of a tram or train. After all, electric motors are highly robust, whereas batteries are not.

Have something to say? Add your comments below. The thread will automatically close 24 hours after publication.