Solar Impulse: the EV airplane

I am posting this because I think it may be of interest the many PriusChat members who have expressed interest in clean energy technology. I apologize to those who may find it off-topic.

Earlier this evening, Mrs. Bear and I had the pleasure of meeting and hearing Andre Borschberg at a gathering co-sponsored by M.I.T. and Swissnex, an organization connecting Switzerland and North America in science, education, art and innovation.

Borschberg is co-founder and pilot of Solar Impulse, the solar-powered electric aircraft which circumnavigated the globe in 2016. Although this was a tremendous technical feat, it also was intended to educate and inform people that the impossible could be possible and that there are many options for our energy future.

He described the solar aircraft as not using new technology but pushing the envelope of existing technologies including PV solar, lithium batteries, and light-weight carbon fiber structure. Solar Impulse was the result of re-thinking the possible, assembling a diverse team, and insisting that each member listen carefully to the perspectives of people expert in technologies other than their own.

The team used a number of ground-breaking technologies including ultrathin solar cells, high-capacity batteries and massive, but light carbon-fiber wings. The aircraft captured sunlight through 17,000 solar cells, each as thin as a human hair, and stored the energy in the batteries later used to power the Solar Impulse II’s four 17-hp motors during hours of darkness.​

Borschberg thinks that the design of an aircraft is less limiting than trying to design an automobile. The automobile is constrained by four wheels and having to operate within the parameters of roads, infrastructure and consumer expectations. In designing an aircraft, one is able to have far fewer constraints to free thinking about the problem -- although free thinking can cause problems with regulatory certifications of something which does not fit easily into existing categories.

(He made a passing comment on General Motors' first attempt a designing an electric car: it was to think about the problem as just the substitution of an electric motor for a gasoline engine. That approach, he noted, was doomed to failure because one needs to think about the entire problem, not just retrofitting one component.)

When asked about practical applications, he cited the possibility of using an electric aircraft for flight training where a student flies for an hour and then is debriefed with the instructor while the aircraft is re-charged for the next student.

Of particular interest to hybrid vehicle owners, he envisions a practical application of electric power for take-off and landing where limiting noise and emissions is important and then using more conventional fuels for efficient cruising.

Tomorrow evening (Wednesday, January 31), the television program Nova will premier a one-hour documentary The Impossible Flight. The program airs at 9 pm on PBS in most U.S. markets. It may be of interest to some of you clean-energy technology aficionados.