World Solar Challenge

Objective

The objective of the challenge is to promote the innovation of solar-powered cars. It is a design competition at its core, and every team/car that successfully crosses the finish line is considered successful. Teams from universities and enterprises participate. In 2015, 43 teams from 23 countries competed in the challenge. Except Nuna team and cars from Delft University of Technology (Netherlands), team from Delft University of Technology (Netherlands), known as the Nuna team and cars, have won eight out of twelve races since 2001. The Tokai Challenger, built by the Tokai University of Japan, won in 2009 and 2011. The Belgian Innoptus Solar Team formerly known as the Agoria Solar Team from KU Leuven University won in 2019 and 2023.

Remarkable technological progress has been achieved since the General Motors led, highly experimental, single-seat Sunraycer prototype first won the WSC with an average speed of 66.9 km/h. Once competing cars became steadily more capable to match or exceed legal maximum speeds on the Australian highway, the challenge rules were consistently made more demanding and challenging — for instance after Honda's Dream car first won with an average speed exceeding 88.5 km/h in 1996. In 2005 the Dutch Nuna team were the first to beat an average speed of 100 km/h.

The 2017 Cruiser class winner, the five-seat Stella Vie vehicle, was able to carry an average of 3.4 occupants at an average speed of 69 km/h. Like its two predecessors, the vehicle was successfully road registered by the Dutch team, further emphasizing the great progress in real-world compliance and practicality that has been achieved.

Challenge strategy

Efficient balancing of power resources and power consumption is the key to success during the challenge. 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 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 driving. To capture as much solar energy as possible, the solar panels are generally directed such that these are perpendicular to the incident sun rays. Sometimes the whole solar array is tilted for this purpose.

Important rules

• The timed portion of the challenge stops at the outskirts of Adelaide, 2998 km from Darwin. However, for the timings recorded at that point to count, competitors must reach the official finish line in the centre of the city under solar power alone.
• As the challenge utilises public roads, the cars have to adhere to the normal traffic regulations.
• 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, 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 route, 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, as well as the difficulties of support crews keeping up with 130 km/h solar 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.
• Entrants to the 2007 event chose between racing in the Adventure and Challenge classes. Challenge class cars were restricted to 6 square meters of Si solar collectors (a 25% reduction), and later to 3 square meters for GaAs, 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 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.
• For the 2009 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. Battery mass is now 20 kg for Li-ion and Li-polymer battery (was reduced from 25 and 21 kg in the past).
• In 2013, a new Cruiser Class was introduced. After the German team of Bochum University of Applied Sciences competed with a four-wheeled, multi-seat car, the BoCruiser (in 2009), in 2013 a radically new "Cruiser Class" was introduced, stimulating the technological development of practically usable, and ideally road-legal, multi-seater solar vehicles. The route took place in four stages. Final placings were based on a combination of time taken (56.6%), number of passengers carried (5.7%), battery energy from the grid between stages (18.9%), and a subjective assessment of practicality (18.9%). Since its inception, Solar Team Eindhoven's four- and five-seat Stella solar cars from Eindhoven University of Technology (Netherlands) won the Cruiser Class in all four events so far.
• In the 2015 Cruiser Class regulations, the scoring formula emphasized practicality less than before. Elapsed time will account for 70% of the score, passengers 5%, grid energy use 15%, and practicality 10%.
• In 2017, solar array areas were reduced, and the Cruiser Class was changed to a Regularity Trial, with scoring based on energy efficiency and practicality.
• In 2025, to slow down the race and show that solar cars are feasible even during winter, the race was shifted by two months to the end of August. To add more emphasis on the solar aspect of the challenge, the solar collector area was also increased to 6 m2 while limiting the battery pack capacity to 11 MJ.

History

The idea for the competition originates from Danish-born adventurer Hans Tholstrup. He was the first to circumnavigate the Australian continent in a 16 ft 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 4052 km between Sydney, New South Wales and Perth, Western Australia in 20 days. That was the precursor of the WSC.

After the 4th event, he sold the rights to the state of South Australia and leadership of the event was assumed by Chris Selwood.

The event was held every three years until 1999 when it was switched to every two years.

1987

Main article: World Solar Challenge 1987

The first edition of the World Solar Challenge was run in 1987 when the winning entry, GM's Sunraycer won with an average speed of 67 km/h. Ford Australia's "Sunchaser" came in second. The "Solar Resource", which came in 7th overall, was first in the Private Entry category.

1990

The 1990 WSC was won by the "Spirit of Biel", built by Biel School of Engineering and Architecture in Switzerland followed by Honda in second place. Video coverage here.

1993

The 1993 WSC was won by the Honda Dream, and Biel School of Engineering and Architecture took second. Video coverage here.

1996

In the 1996 WSC, the Honda Dream and Biel School of Engineering and Architecture once again placed first and second overall, respectively.

1999

Main article: 1999 World Solar Challenge

The 1999 WSC was finally won by a "home" team, the Australian Aurora team's Aurora 101 took the prize while Queen's University was the runner-up in the most closely contested WSC so far. The SunRayce class of American teams was won by Massachusetts Institute of Technology.

2001

Main article: World Solar Challenge 2001

The 2001 WSC was won by Nuna of the Delft University of Technology from the Netherlands, participating for the first time. Aurora took second place.

2003

Main article: World Solar Challenge 2003

In the 2003 WSC Nuna 2, the successor to the winner of 2001 won again, with an average speed of 97 km/h, while Aurora took second place again.

2005

Main article: World Solar Challenge 2005

In the 2005 WSC the top finishers were the same for the third consecutive event as Nuon's Nuna 3 won with a record average speed of 102.75 km/h, and Aurora was the runner-up.

2007

Main article: World Solar Challenge 2007

The 2007 WSC saw the Dutch Nuon Solar team score their fourth successive victory with Nuna 4 in the Challenge Class, averaging 90.07 km/h under the new, more restrictive rules, while the Belgian Punch Powertrain Solar Team's Umicar Infinity placed second.

The Adventure Class was added this year, run under the old rules, and won by Japanese Ashiya team's Tiga.

The Japanese Ashiya team's Tiga won the Adventure Class, run under the old rules, with an average speed of 93.53 km/h.

2009

Main article: World Solar Challenge 2009

The 2009 WSC was won by the "Tokai Challenger", built by the Tokai University Solar Car Team in Japan with an average speed of 100.54 km/h. The longtime reigning champion Nuon Solar Team's Nuna 5 finished in second place.

The Sunswift IV built by students at the University of New South Wales, Australia was the winner of the Silicon-based Solar Cell Class, while Japan's Osaka Sangyo University's OSU Model S won the Adventure class.

2011

Main article: World Solar Challenge 2011

In the 2011 WSC Tokai University took their second title with an updated "Tokai Challenger" averaging 91.54 km/h, and finishing just an hour before Nuna 6 of the Delft University of Technology. The challenge was marred by delays caused by wildfires.

2013

Main article: World Solar Challenge 2013

The 2013 WSC featured the introduction of the Cruiser Class, which comprised more 'practical' solar cars with 2–4 occupants. The inaugural winner was Solar Team Eindhoven's Stella from Eindhoven University of Technology in the Netherlands with an average speed of 74.52 km/h, while second place was taken by the PowerCore SunCruiser vehicle from team Hochschule Bochum in Germany, who inspired the creation of the Cruiser Class by racing more practical solar cars in previous WSC events. The Australian team, the University of New South Wales solar racing team Sunswift was the fastest competitor to complete the route, but was awarded third place overall after points were awarded for 'practicality' and for carrying passengers.

In the Challenger Class, the Dutch team from Delft University of Technology took back the title with Nuna 7 and an average speed of 90.71 km/h, while defending champions Tokai University finished second after an exciting close competition, which saw a 10–30 minute distance, though they drained the battery in final stint due to bad weather and finished some 3 hours later; an opposite situation of the previous challenge in 2011.

The Adventure Class was won by Aurora's Aurora Evolution.

2015

The 2015 WSC was held on 15–25 October with the same classes as the 2013 challenge.

In the Cruiser Class, the winner was once again Solar Team Eindhoven's Stella Lux from Eindhoven University of Technology in the Netherlands with an average speed of 76.73 km/h, while the second place team was Kogakuin University from Japan who was the first to cross the finish line, but did not receive as many points for passenger-kilometers and practicality. Bochum took 3rd place this year with the latest in their series of cruiser cars.

In the Challenger Class, the team from Delft University of Technology retained the title with Nuna 8 and an average speed of 91.75 km/h, while their Dutch counterparts, the University of Twente, who led most of the challenge, finished just 8 minutes behind them in second place, making 2015 the closest finish in WSC history. Tokai University passed the University of Michigan on the last day of the event to take home the bronze.

The Adventure Class was won by the Houston High School solar car team from Houston, Mississippi, United States.

2017

The 2017 WSC was held on 8–15 October, featuring the same classes as 2015. The Dutch NUON team won again in the Challenger class, which concluded on 2017-10-12, and in the Cruiser Class, the winner was once again Solar Team Eindhoven, from the Netherlands as well.

2019

The 2019 WSC was held from 13 to 20 October. 53 teams from 24 countries entered the competition, In the Challenger class, Agoria Solar Team (formerly Punch Powertrain) won for the first time. Tokai University Solar Car Team finished in second place.

In the Cruiser class, Solar Team Eindhoven won their fourth consecutive title. Despite multiple incidents on the road, Team Sonnenwagen Aachen managed to beat other teams and finished in 6th position.

Several teams had mishaps. Vattenfall was leading when their car Nuna X caught fire. The driver was uninjured, but the vehicle was destroyed. It was the first no-finish for that team in 20 years. Others were badly affected by strong winds.

Dutch team Twente was leading the journey at 100 km/h, when their car was forced off the road by winds and rolled over. The driver was taken to hospital. Within 30 minutes team Sonnenwagen Aachen was also blown off the road north of Coober Pedy, the driver was not hurt. An 80 km/h speed limit was then imposed by event officials, lifted when conditions improved. The day before, wind damage to solar panels put the team from Western Sydney University out of the challenge. The driver of Agoria from Belgium escaped injury when their vehicle was "uprooted" at 100 km/h (62 mph) by severe winds, but still went on to win the Challenger class.

2021

In response to the COVID-19 pandemic in Australia the WSC closed entries three months earlier than normal, on 18 December 2020. They were then to "… review all current government measures relating to social distancing, density and contact tracing, international travel restrictions and isolation requirements." On 12 February 2021, the South Australian Government confirmed the cancellation of the 2021 staging of the event. While the COVID-19 pandemic was not explicitly cited as the reason, the "complexities of international border closures" affecting Australia at the time appear to be the primary reason for the event's cancellation. The same statement also noted the next event would take place in October 2023 - at least 962 days from the date of announcement, and resulting in a four-year gap between events. Registered teams should receive a full refund of all fees.

2023

The 2023 World Solar Challenge was held from October 22-29. At the beginning of the race, 31 teams were participating, with 23 in the Challenger division and 8 in the Cruiser division. The Challenger division was won by defending champions Innoptus (formerly Agoria) with an average speed of 88.2km/h, and the Cruiser division was won by UNSW Sunswift with a score of 91.1. Uniquely, no Cruisers were able to finish the race this year.

Many of the leading teams faced trouble during the competition. Dutch team Top Dutch raced on a perovskite-tandem solar array damaged from testing in the month leading up to race. Michigan experienced electrical issues during qualifying and had to start last. German team Sonnenwagen was blown off the road just outside of Port Agusta and had to withdraw due to new regulations. Tokai had to stop for several hours on Day 4 to repair their car after sustaining damage from crossing a cattle grid. Kogakuin had consistent problems with their MPPT charge controller, and reported in an Instagram post that their panels were generating less than half the power than they should have been. On the fifth day of the competition, only 4 teams (Innoptus, Twente, Brunel, and Michigan) had finished the course, and by the official end of timing, only 12 teams made it to the finish line successfully.

2025

The 2025 World Solar Challenge was held from August 24-31, with an entry of 34 teams. The new regulations have allowed for an increase in solar array size from 4m2 to 6m2. Also the race was the first held in the Australian winter, creating cooler conditions for drivers but reduced sunlight, increasing the challenge. The Brunel Solar Team from the Netherlands won, narrowly beating fellow Dutch team Twente and Belgium’s Innoptus. Brunel’s katamaran Nuna 13 featured two side fins to capture wind for extra speed and stability. Notably, the field saw four different teams with fin-like aerodynamic thrust devices on their cars. The concept, while being explored previously, has gained major interest from teams after Innoptus Solar Team’s 2023 win with such a device on their car.

Event Safety Award - Eclipse solar car

Bridgestone Australia E8 Commitment Award - Iron Lions Racing

CSIRO Technical Innovation Award - Onda Solare - Università di Bologna

References

References

1. (2017). "Mission: Serving Society with Superior Quality". Bridgestone.
2. (9 February 2021). "History". South Australian Tourism Commission.
3. (5 June 2015). "2015 Team List". World Solar Challenge.
4. (23 August 2017). "Stella Vie is officially road legal!".
5. (6 August 2017). "KENTEKEN CHECK PP-301-S (Dutch public registration info for license-plate PP-301-S)". Autoweek.nl.
6. (8 September 2016). "An epic journey revisited". National Museum of Australia.
7. (22 October 2003). "RACING; Here They Come, as Fast as the Sun Will Carry Them". The New York Times.
8. [http://140.112.14.7/~ifplab/solar/team.htm#1987 1987 World Solar Teams] IFP Lab Site, Retrieved 13 February 2021.
9. (1 October 1998). "History of the Electric Automobile". SAE International.
10. [http://140.112.14.7/~ifplab/solar/team.htm#1990 1990 World Solar Challenge Teams] IFP Lab Site, Retrieved 13 February 2021.
11. [http://140.112.14.7/~ifplab/solar/team.htm#1993 1993 World Solar Challenge Entry List] IFP lab site, Retrieved 13 February 2021.
12. [http://140.112.14.7/~ifplab/solar/team.htm#1996 1996 World Solar Challenge Team] IFP Lab Site, Retrieved 13 February 2021.
13. [http://140.112.14.7/~ifplab/solar/team.htm#1999 1999 World Solar Challenge Teams] IFP Lab Site, Retrieved 13 February 2021.
14. (27 November 2001). "Final Results for the 2001 Solar Odyssey". World Solar Challenge.
15. "Teams List 2001". World Solar Challenge.
16. (4 June 2014). "Honour Roll - 1987 to 2013". World Solar Challenge.
17. [https://www.twikeklub.ch/images/1_2007_Final_Results.pdf WSC 2007 results]
18. [http://www.worldsolarchallenge.org/files/70_history_results-to-date.pdf WSC 2009 results]
19. [http://www.worldsolarchallenge.org/files/17_final_results_document_audited.pdf WSC 2011 results]
20. "WSC 2013 Cruiser class results".
21. [http://www.worldsolarchallenge.org/files/492_final_results_sunday_challenger_class.pdf WSC 2013 Challenger class results]
22. "WSC 2013 Adventure class results".
23. [http://www.worldsolarchallenge.org/files/1492_v3_official_times_cruiser_class_display.pdf WSC 2015 Cruiser class results]
24. [http://www.worldsolarchallenge.org/files/1489_2015_bwsc_challenger_class_outright_results.pdf WSC 2015 Challenger class results]
25. (6 November 2015). "WSC 2015 Adventure class results". World Solar Challenge.
26. "2017 World Solar Challenge Results". World Solar Challenge.
27. "CHARGING THE FUTURE – NEXT-GEN DREAMS TO REALITY {{!}} World Solar Challenge 2019".
28. (19 October 2019). "Chasing the sun: the World Solar Challenge 2019". The Guardian.
29. (17 October 2019). "Agoria claims first title". South Australian Tourism Commission.
30. (21 October 2019). "It's cruise control all the way for Solar Team Eindhoven". South Australian Tourism Commission.
31. (17 October 2019). "Leading car at World Solar Challenge bursts into flames forcing team Vattenfall out of challenge". Australian Broadcasting Corporation.
32. (16 October 2019). "Two cars blown off road during World Solar Challenge near Coober Pedy". Australian Broadcasting Corporation.
33. (7 October 2020). "COVID-19 and the Bridgestone World Solar Challenge". South Australian Tourism Commission.
34. "Charging towards the future…31 teams off to chase the sun… {{!}} World Solar Challenge 2023".
35. "World Solar Challenge 2023".
36. "World Solar Challenge 2023".
37. "Day 5: We are out of the race!".
38. "Instagram".
39. "Event Regulations".
40. (24 August 2025). "Solar-powered cars start epic Australian outback race". BBC News.
41. (28 August 2025). "Dutch team 'back from the ashes' of 2019 fire to win World Solar Challenge".