And then I went over to Youtube and searched for “Solar Impulse”. The top video is this documentation of their flight across the United States:
It shows that this project is a great success.
Not necessarily as aviation technology. I am not convinced that solar and aviation are a good match. The main limitation is speed, as a result of having less power available compared to fossil fuel.
The power of the engine is 6 kW, which is about equivalent to the first flights of the Wright brothers. That results in a cruising speed of 70 km/h, which is slow for aviation. If you don’t mind going that slow, an airship like the Aeroscraft is the better alternative.
But this project clearly is a large success as a media project, and as a PR campaign for solar power. Just look at the people in their video above, including Larry Page, Richard Branson, and Ban Ki-Moon.
Railways have been the first to move away from firing coal. Now most of them are running on electricity. Cars will be next. And air traffic will take the longest, since it is so difficult to store energy on board with heavy batteries.
But exactly the fact that it is so difficult to pull off makes this project interesting. And exactly that is the value of the “Solar Impulse” project to advancing the cause of solar energy.