World Solar Challenge
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The race attracts teams from around the world, most of which are fielded by universities or corporations although some are fielded by high schools. The race has a 20-year history spanning nine races, with the inaugural event taking place in 1987.
The objective of this competition is to promote research on solar-powered cars. Teams from universities and enterprises participate. In 2005, 22 teams from 11 countries entered the primary race category.
Racing strategy 
Efficient balancing of power resources and power consumption is the key to success during the race. At any moment in time the optimal driving speed depends on the weather (forecast) and the remaining capacity of the batteries. The team members in the (normal) escort cars will continuously remotely retrieve data from the solar car about its condition and use these data as input for prior developed computer programs to work out the best driving strategy.
It is equally important to charge the batteries as much as possible in periods of daylight when the car is not racing. To capture as much solar-energy as possible, the solar panels are generally directed such that these are perpendicular to the incident sun rays. Often the whole car is tilted for this purpose.
Important rules 
- As the race is over public roads, the cars have to adhere to the normal traffic regulations; however, there is a special note in the official regulations remarking on the tendency of drivers to take advantage of a favourable road camber in order to capture the maximum amount of solar energy. After midday when the sun is in the west, it would be advantageous to drive on the right side of the highway, provided, of course, there is no traffic in opposite direction.
- A minimum of 2 and maximum 4 drivers have to be registered. If the weight of a driver (including clothes) is less than 80 kg (180 lb), ballast will be added to make up the difference.
- Driving time is between 8:00 and 17:00 (from 8 a.m. to 5 p.m.). In order to select a suitable place for the overnight stop (alongside the highway) it is possible to extend the driving period for a maximum of 10 minutes, which extra driving time will be compensated by a starting time delay the next day.
- At various points along the route there are checkpoints where every car has to pause for 30 minutes. Only limited maintenance tasks (no repairs) are allowed during these compulsory stops.
- The capacity of the batteries is limited to a mass for each chemistry (such as Lithium Ion) equivalent to approximately 5 kWh maximum. At the start of the race, the batteries may be fully charged. Batteries may not be replaced during the competition, except in the situation of a breakdown. However, in that case a penalty time will apply.
- Except for the maximum outer dimensions, there are no further restrictions on the design and construction of the car.
- The deceleration of the dual braking system must be at least 3.8 m/s² (149.6 in/s²).
Rule evolution 
By 2005, several teams were handicapped by the South Australian speed limit of 110 km/h (68 mph), as well as the difficulties of support crews keeping up with 130 km/h (81 mph) race vehicles. It was generally agreed that the challenge of building a solar vehicle capable of crossing Australia at vehicular speeds had been met and exceeded. A new challenge was set: to build a new generation of solar car, which, with little modification, could be the basis for a practical proposition for sustainable transport.
2007 race 
Entrants to the 2007 race chose between racing in the Adventure and Challenge classes. Challenge class cars were restricted to 6 square meters of solar collectors (a 25% reduction), driver access and egress were required to be unaided, seating position upright, steering controlled with a steering wheel, and many new safety requirements were added. Competitors also had to adhere to the new 130 km/h (81 mph) speed limit across the Northern Territory portion of the Stuart Highway.
The 2007 event again featured a range of supplementary classes, including the Greenfleet class, which features a range of non-solar energy-efficient vehicles exhibiting their fuel efficiency.
2009 race 
For the challenge class several new rules were adopted, including the use of profiled tyres. Battery weight limits depend on secondary cell chemistries so that competitors have similar energy storage capabilities.
The idea for the competition originates from Danish-born adventurer Hans Tholstrup. He was the first to circumnavigate the Australian continent in a 16-foot (4.9 m) open boat. At a later stage in his life he became involved in various competitions with fuel saving cars and trucks. Already in the 1980s, he became aware of the necessity to explore sustainable energy as a replacement for the limited available fossil fuel. Sponsored by BP, he designed the world's first solar car, called The Quiet Achiever, and traversed the 4,052 km (2,518 mi) between Sydney and Perth in 20 days. That was the precursor of the World Solar Challenge.
After the 4th race, he sold the rights to the state of South Australia and leadership of the race was assumed by Chris Selwood.
The race was held every three years until 1999 when it was switched to every two years.
- The first race was run in 1987 when the winning entry, GM's Sunraycer won with an average speed of 67 km/h (42 mph). Ford Australia's "Sunchaser" was second and "Spirit of Biel" was third. The "Solar Resource", which came in 7th overall, was first in the Private Entry category.
- In 1990 the race was won by the "Spirit of Biel", built by Biel School of Engineering and Architecture in Switzerland followed by Honda in second place and University of Michigan in third. Video coverage here.
- In 1993 the race was won by Honda. Video coverage here.
- In 1996 the race was won by Honda for a second time.
- Finally in 1999 a "home" team, the Australian "Aurora", took the prize.
- In 2001 the Nuna of the Delft University of Technology from the Netherlands, participating for the first time, was the fastest.
- In 2003 the Nuna 2, the successor to the winner of 2001 won again, with an average speed of 97 km/h (60 mph).
- In 2005 the Nuna team scored a hat-trick with their third victory in a row; their Nuna 3 won with a record average speed of 102.75 km/h (63.85 mph). Aurora finished in second place followed by the University of Michigan in third.
- In 2007 the Dutch Nuon Solar team scored their fourth successive victory with Nuna 4 in the challenge class averaging 90.07 km/h (55.97 mph) under the new rules, while the Ashiya team with their car Tiga won the race in the adventure class under the old rules with an average speed of 93.53 km/h (58.12 mph).
- In 2009 the race was won by the "Tokai Challenger", built by the Tokai University Solar Car Team in Japan. The Dutch Nuon Solar Team's Nuna 5 finished in second place followed by the University of Michigan in third. The first Australian car across the line was Sunswift IV built by students at the University of New South Wales which came in fourth overall and was the first silicon-based cell car to finish.
|Race||Year||Class||Vehicle Number||Winner||Team||Country||Total racetime (hrs:min)||Average Speed (km/h)|
|1.||1987||23||Sunraycer||General Motors||United States of America||44:54||66.9|
|2.||1990||38||Spirit of Biel/Bienne II||Engineering College of Biel||Switzerland||46:08||65.2|
|5.||1999||Open Class||43||Aurora 101||Aurora Vehicle Association/RMIT University||Australia||41:06||73.0|
|Sunrayce Class||6||Manta GTX||MIT||USA||45:34||65.81|
|6.||2001||37||Alpha Centauri Team
|7.||2003||33||Nuon Solar Team
|8.||2005||30||Nuon Solar Team
|9.||2007||Challenge||23||Nuon Solar Team
|10.||2009||Challenge||32||Tokai Challenger||Tokai University||Japan||29:49||100.54|
|Challenge Class Silicon||25||Sunswift IVy||University of New South Wales||Australia||39:18||76.28|
|Adventure||24||OSU Model S'||Osaka Sangyo University||Japan||34:45||86.27|
|11.||2011||Challenge||1||Tokai Challenger||Tokai University||Japan||32:45||91.54|
See also 
Other solar vehicle challenges 
- North American Solar Challenge, a biennial US event that includes Canada since 2005
- The Solar Car Challenge, an annual event for High School students from the US and (to a lesser extent) other parts of the world, first held in 1995
- South African Solar Challenge, a biennial South African event that is to be held for the first time in 2008
- Victorian Model Solar Vehicle Challenge, an annual event in Australia for schoolchildren
- The Cyprus Institute Solar Car Challenge 2010, is the first solar-vehicle race in Cyprus
- Race The Sun, a movie loosely based on a participating team
- World Solar Challenge Homepage
- Global Green Challenge Homepage
- Wakefield, E.H. History of the Electric Automobile: Hybrid Electric Vehicles. Washington: SAE International.
|Wikimedia Commons has media related to: World Solar Challenge|
- Official site
- Images from Alice Springs, Australia - 2007
- An overview of all the competing teams in the 2013 WSC.
- Helios  is a French student association from Lille which design and make solar cars since 1992.