Solar Impulse: Moving solar energy from poetry to practicality

Solar Impulse is spending the week in Washington, DC, and the C&EN headquarters is slightly abuzz with geeky giddiness. So, living a mere 15 minutes from the solar plane's temporary home in a hangar at the Smithsonian's Udvar-Hazy Center next to Dulles International Airport, I couldn't resist the invitation to a Solvay-sponsored event with the pilots and crew on Tuesday evening. Melody twisted my arm kindly invited me to write about my visit for the Cleantech crowd.
Solar Impulse in DC

Solar Impulse in its temporary home at the Smithsonian's Air & Space Museum Stephen F. Udvar-Hazy Center in Chantilly, Virginia Credit: Rachel Pepling

I had to walk past the ginormous Discovery space shuttle, which is spending retirement at the Udvar-Hazy Center, then dodge raindrops to get to the the temporary hangar housing Solar Impulse just outside of the museum. The rainy weather and mugginess of the hangar didn't exactly create the setting you'd expect for admiring a plane that runs on energy from the sun. But I digress. Compared to the robust space shuttle, the solar plane looks like an oversized toy glider. As Alex Scott pointed out in his article on the chemistry behind Solar Impulse, the plane has a wingspan about the same as a 747's but weighs about the same as a small sedan. There is no other way to describe the cockpit than as tiny. It's basically a chair with a bubble over it. And, of course, there are lots and lots of solar panels. Before the pilots' presentation, I was in a group chatting with a member of Solar Impulse's communications team. When asked about the plane's assembly at Moffett Airfield near San Francisco, she explained that it took the team basically three days to put the plane together and equated the process to assembling furniture from IKEA. No nails, just glue. Hopefully, no leftover parts. It is, apparently, that amazingly simple. Bertrand Piccard was the first of the two pilots to speak. His psychiatry background came through as he talked about changing your altitude in order to fight against the winds while in a balloon. My mind was starting to drift away a bit when he brought me back with this line: "This is all very poetic, but useless. Let's make it practical." He then showed a picture taken at the end of his around-the-world-in-a-balloon mission in 1999. "Many people think this is the last picture of a balloon trip," he said. "In fact, it is the first picture of Solar Impulse." Piccard then shared that it was the amount of fuel spent on the trip and that there was only 40 kilos left at the end that ignited the Solar Impulse project. André Borschberg spoke more about how the plane actually works. While listening to him, I came to realize that Solar Impulse epitomizes the theme of the fall national meeting in Indy: Chemistry in Motion. Without chemistry (again, read Alex's excellent article), this plane would have never taken flight. Hearing Piccard and Borschberg speak and looking up-close at the plane was all very cool, but I'm left with the feeling of "What next?" Borcshberg pointed out that they had considered making the plane large enough to accommodate two people, but safety became an issue. So to me, at this point, Solar Impulse is really just a proof of concept. Under certain conditions, one can indeed travel long distances at both night and day using only solar power. But I go back to Piccard's statement earlier and wonder how do we move from poetic to practical? Certainly, the materials created for this plane will find new uses elsewhere and to make our current vehicles greener, but we're still pretty far away from using only solar to get us in motion. Or is Solar Impulse's role as a solar energy, nay, innovation ambassador enough for now?

Author: Rachel Pepling

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