Now I have to admit that simple rules of conduct are often imperative, but it would be sometimes helpful to better understand why a change in our daily behaviour is useful. For this reason I pursued the question Bertrand asked me: "How much electricity can be saved by the use of energy saving lamps"?

With the support of Marcus Basien, chief engineer of Solar Impulse, I made the following calculation: In Switzerland roughly 7.5 million people live in 3’436’000 households with an average of 26 lamps installed. About 53 percent, thus 47’348’080, are incandescent bulbs that are on for one hour a day. Now, if all these lamps with an average consumption of 60 watts per hour would be replaced by equally bright 15-watt energy saving bulbs, 2’130’663’600 watt hours of electricity could be saved each day. To put this into a different perspective: with this energy, our solar aircraft HB-SIA could stay airborne for 38 years and circle earth at least 328 times! Sounds surreal? But not as absurd as wasting huge amounts of energy day by day.