Racing with the sun

In December 1982, the Quiet Achiever was at the leading edge of solar car technology. Powered by the sun's rays, Danish adventurer Hans Tholstrup drove it right across Australia in just under three weeks, at an average speed of about 23 km/h.

Fast forward a quarter-century. The cars in this summer's North American Solar Challenge, including four teams from Canadian universities, would leave the Quiet Achiever in their environmentally friendly dust.

Drivers in the race must abide by posted speed limits as they travel more than 3,800 kilometres from Texas to Calgary. Since some solar cars can top speeds of 160 km/h — worthy of a hefty speeding fine in most places — the rule is not just for show.

Teams from Queen's University, the University of Calgary, the University of Waterloo and Red River College in Manitoba are competing in this year's challenge, which started July 13 and ends July 22.

Another key rule: The cars can rely only on the power of the sun and what can be stored in a battery in the vehicle. As a power source equivalent to several conventional car batteries, it can power a solar car for hundreds of kilometres, even on a cloudy or rainy day.

Strategy and teamwork are both key to keeping up the speed in the race, says Leon Fainstein, senior faculty adviser to the Red River College team. So is the technology behind the solar cars, which has improved greatly in recent years.

The solar panels used to collect the sun's rays for energy have gone from five per cent energy efficiency to above 50 per cent in recent years, Fainstein says. The motor of the Red River car participating in this year's challenge is also 95 per cent fuel efficient, meaning "virtually nothing" is wasted in powering it. (Compare that to 40 per cent efficiency on a conventional car.)

"It's the Tour de France of engineering," Fainstein says of the solar challenge. "It's an endurance test of both man and machine."

Extreme efficiency

Driving certainly can be uncomfortable for the solar car's lone occupant. During the early days of this year's challenge, temperatures topped 45 Celsius in Texas, which would be even hotter in the driver's seat with no air conditioning.

A radio and many other conveniences are also nowhere to be found.

Extreme energy efficiency is the key to getting a car across North America without a gas fill-up. Building in that efficiency takes time, and lots of it.

Fainstein estimates it took 15,000 hours to build the Raycer, which debuted in the 2005 Solar Challenge. Another 7,500 hours (an estimate that doesn't include large amounts of faculty overtime) were needed to modify the car for this year's event.

Over at the Queen's University team, project manager Nate Preston says working on this project "made me realize how much we rely on our vehicles, but don't stop to think about how inefficient they really are."

"We have a 1,200-watt solar array," he tells CBCNews.ca as the team cruises through the flatlands of South Dakota. "We can use that to either power a microwave or get us across the continent."

There will be no huge windfalls from gas savings, though. Even with students doing the work, the Queen's Aurum car cost "several hundred thousand" dollars to build, Preston says. That's a bargain compared to the $1-million-plus budgets of some U.S. universities for their entries.

Other schools, such as Red River, work on tighter budgets. The Raycer was completed on a $120,000 budget, financed in part by sponsors like the province of Manitoba.

A whale of a car

The entries in this year's North American Solar Challenge come in a variety of shapes and sizes. In addition those shaped like flying saucers and manta rays, some racers say that one entry looks a bit like a whale. Another resembles a pyramid on wheels.

The cars are built in a variety of shapes because of different ideas for overcoming the single biggest challenge in solar car design — aerodynamic drag. Almost 90 per cent of a vehicle's energy is used trying to get past the power of the wind.

The cars have also become slightly lighter in recent years, says Howie Lau of the University of Waterloo's team. Its car, the Midnight Sun IX, has slimmed down from about 320 kg to 272 kg (including the driver) over the past few generations of development.

So, the cars are light, require the energy output of a hair dryer and have some pep on the open road — but will they be coming to a driveway near you soon?

"I don't think so," said Daniel Uhlord, a member of the SolarWorld 1 team from Hochschule Bochum University in Germany. "They're not quite up for the challenge of everyday life."

But solar energy could still play a significant role in a future transportation society less dependent on oil.

Uhlord and others envision an electric "solar-assisted" car with cellphone-like batteries that charge in the morning sun while you sip your coffee, then recharge in a parking lot while you toil away at work.

Whether that car would look like a whale, UFO or just a souped-up sedan is yet to be determined.