The Solartaxi was the firstsolar powered car to complete an around-the-world trip in 2008 – it did need to haul a trailer with solar panels on it to generate the required amount of electricity. This year, not only are students from Bochum University in Germany currently driving around the world in a solar-powered car (without a trailer) but in May, the Tûranor PlanetSolar became the first solar-powered boat to successfully circumnavigate the globe.
After 19 months at sea, the Tûranor returned to Monaco where it had originally set off from in the autumn of 2010. The catamaran is 35m long, 23m wide and weighs 95t. The top of the boat is covered in panels of photovoltaic cells which cover an area of 5372 .
If we can go around the world with a solar boat then everybody can use renewable energies for everyday applications at home
The cells generated electricity for the propellers as well as the auxiliary systems. Raphaël Domjan, who led the expedition, tells Humans Invent, “The surplus energy was stored for use at night or in bad weather and also supplied electricity for the satellite, telephone, computer, shower and the lights on board.”
It is a great achievement in its own right but is it indicative of a future where all (non-sailing) ships will be solar powered? Domjan seems cautious. He says, “We are not saying that it is possible to do everything with solar energy. I don’t believe it is possible for big boats, really big boats, to run just on solar energy. The problem is that they don’t have enough square meters of solar cells for the weight that you have to carry but it is possible to have smaller boats run on solar energy, this is possible.”
The solar-powered speeder
In October 2010, a car powered by Sharp’s compound solar cells triumphed for a second consecutive time in an 11-day solar car race around South Africa.
The Tokai Challenger, built by a team from Tokai University in Japan, beat its rivals to the finish line after navigating a 4061km course that started and finished in Pretoria and passed through Johannesburg and Cape Town. It hit an average speed of 90.1km/h during its journey.
The Sharp solar cells which power the Tokai Challenger have a cell conversion efficiency of 30%, the highest level in the world, with an output of 1.8kW. The same panel design is used by NASA to power part of the Kennedy Space Center.
The solar panels on the Tûranor took up the majority of space on the boat and there were only four members of crew. Ultimately, the point of the expedition was to raise awareness about the power of renewable energy. Domjan says, “We are saying that if we can go around the world with a solar boat then everybody can use renewable energies for everyday applications at home.”
Now both the solar car and the solar boat have been around the world the next plan among renewable energy pioneers is to fly a solar-powered plane around the world. The project is being led by Bertrand Piccard who, along with Brian Jones, completed the first around-the-world balloon flight in 1999. So far the plane has been tested and has flown both in the day and at night. The plan is to circumnavigate the globe in 2014. Although the plane has the same wingspan as an Airbus A340 it only weighs 1600kg, which is about the same weight as a family car. Over 11,000 monocrystalline silicon cells cover the wings and the horizontal stabilizer that convert the sun’s rays into electricity. The solar cells both feed the engine and recharge the batteries, which means the plane can run on the batteries at night.
The aviation industry knows it must evolve but it can’t do it as quickly as we have done with Solar Impulse. Our project is zero fuel
As with the solar boat, the plane can only contain a limited amount of people, in this case only 2, with most space taken up by the solar panels. Solar Impulse, the team developing the solar plane, is aware that the commercial viability of solar planes is still a long way off.
A spokesman told Humans Invent, “The aviation industry knows it must evolve but it can’t do it as quickly as we have done with Solar Impulse. Our project is zero fuel. Conventional aviation will not be able to achieve zero fuel right away. Intermediate steps are needed, like the use of lighter materials.”
Their aim also is to raise awareness about the potential use for renewable energy in our everyday lives: “What we can achieve in the air, anyone can do on the ground. If the technologies we have for Solar Impulse were massively used, the world would be able to save up to 50% of the current consumption of fossil energy and produce half the rest with renewables.”
Leading Solar panel manufacturer Sharp, who have been developing solar cells since 1959, believe the achievements are justification that solar power has an important role to play in the future of renewable energy. Matthias Kauser, Research Manager in the Advanced Optoelectronics Devices Group. explains: “The circumnavigation of the globe by a solar boat and the development of solar planes are exciting because they show how advanced solar technology has become. We are already generating electricity reliably in all weather conditions but there is still enormous room for making solar panels even more efficient in the future.”
While innovation in solar travel continues to drive the possibilities of bringing solar closer to homes across the world, the debate continues as to what the future for solar is. If success stories continue to emerge the planet will be hard pushed to find a more efficient renewable energy. As Sir James Dyson told Humans Invent, innovation is the answer: “Good technology should solve problems” says Dyson. “Existing PV cells are heavy and only have limited applications. The technology should better fit into its surroundings, so you don’t even notice them.”