In the western corner of Switzerland, two teams are vying to be the first to circle the Earth using solar-powered craft. It's not officially a competition, but the similarity of the projects, the geographic proximity, and the chance to lead in a field with huge potential make it one.
PlanetSolar was announced in March in Yverdon, a city one hour from Geneva. There, a group organized around the local engineering school unveiled a strange, swan-like object with a long white beak (a "wavepiercer") protruding from a three-hulled body covered with 1,930 square feet of solar panels. It's a scaled-down model of a solar trimaran.
The other team, Solar Impulse, has been working for two years now at the Swiss Federal Institute of Technology in Lausanne, just half an hour south of Yverdon. The team wants to circumnavigate the Earth in a single-pilot solar-powered aircraft. With 2,700 square feet of monocrystalline solar cells atop the wings, the craft will be capable of taking off with its own power and staying aloft day and night. (Flying when the sun is "off" is the hardest problem to address.)
Both projects aim to demonstrate the potential of solar by using attention-grabbing challenges to raise public awareness of the need for sustainability and clean energy and to promote a more respectful attitude towards the environment.
The men behind PlanetSolar are Raphael Damjan, a 34-year-old globetrotter and glider pilot, and Mark Wüst, who heads the tech department for a firm behind several solar-powered boats operating on small lakes and rivers across Europe. This, however, is a project of a different scale: to build a trimaran (picture left) capable of transporting two people (Damjan and possibly a famous sailor whose name has not been revealed) around the world using nothing more than the energy of the sun. The solar panels should be sufficient to produce 30 kilowatts of power and sail at 15 knots.
The team plans its first trip around the Earth in 2008 or 2009, a solar-powered voyage along an equatorial route and in several legs. If everything goes well, in 2010 or 2011 they will attempt a nonstop circumnavigation in 80 days -- any resemblance to Phileas Fogg is intentional -- following the route of the Vendée Globe boat race (which goes through such challenging waters as those of Cape Horn). For this trip they plan to add hydrogen power to the mix, to increase the boat's speed and autonomy.
At the moment, though, the trimaran is still just a vision (and two video simulations on their Web site). The financing isn't much more tangible, either.
As Wüst told the press during the presentation of the project, "Solar is right now a relatively poor proposition for cars...but it's perfectly attuned to maritime traffic. With 6 kW you can transport two people in a car, or 20 on a boat, because boats don't have to accelerate and decelerate and stop and start as often." Not to mention that boats offer larger potential surfaces for panels and are less constrained when it comes to carrying batteries.
Solar planes are a much more complex endeavor, but Solar Impulse comes with solid credentials. It's the brainchild of Swiss explorer and scientist Bertrand Piccard, 48, whose grandfather was the first man to reach the stratosphere in a balloon and whose father went first to the deep end of the oceans -- the Mariannes -- in a bathyscaphe. Unable to beat them up or down anymore, Piccard went horizontal, and in March, 1999, together with Brian Jones of Britain, completed the first-ever nonstop round-the-world flight in a hot-air balloon.
In its current design, the Solar Impulse aircraft (picture right) will have a wingspan of 80 meters, nearly that of the new double-decker Airbus A380. It will weigh about 2 tons, much of it from batteries that will store the energy accumulated during daylight to permit night flight. Two engines should provide 40 horsepower of thrust. During the night, the plane will glide to save energy, dropping from 10,000 meters to 3,000 meters, and then climb back during the day.
Piccard and his team are planning the first test flights in 2008, and a transatlantic flight (the Lindbergh route, New York to Paris) in 2009. If everything goes well, they think they can be ready for a three-leg tour of the world in 2010. Unlike the trimaran team, Solar Impulse has already lined up half of the total funding of 40 million euros and at least four major sponsors (multinational Solvay, engineering groups Dassault and Altran, and a fourth one whose name will be announced this week), not to mention the help of the European Space Agency.
Like small solar boats, sun-powered planes have been around for a while. A craft called Solar Challenger flew the English Channel in 1981. In 1990 Eric Raymond crossed the U.S. in 21 stages, the longest being 400 km, over a period of 2 months in his solar glider Sunseeker. NASA has been working on pilotless drones, one of which (called Helios) crashed in the Pacific Ocean in 2003 after reaching a record altitude of 30,000 meters, while another, dubbed SoLong, flew for 24 hours over the Mojave Desert in California last year.
The adventure and the race to be first in circling the globe by solar is certainly a big part of the Solar Impulse and the PlanetSolar stories. What's more interesting, however, is that both groups will face significant design and engineering challenges. To succeed, they will have to produce major advances in materials and composite structures, which need to be solid and lightweight; ultra-efficient solar energy capture and storage, or cells and batteries, respectively; aerodynamics; propulsion; and even human physiology monitoring, in the case of the airplane; meteorology; and routing, to follow the energy source -- the sun. Which makes them -- assuming that they will fly and float -- powerful catalysts for solar technology developments that could lead to applications in many other fields.
Says Piccard: "We need to show people that renewable energy is not a step backwards but a jump into the future: if we can go around the world in a solar aircraft, that means that we can do incredible things with renewables".