5 August 2005Miguel Llanos
Mile after mile along this stretch of Canada's coast-to-coast highway, the faces of the farmers, truckers and oil workers who turned to look had the same dumbfounded expression, as if asking: What the heck were those? UFOs on wheels? Stealth fighters with their wings clipped? Supersized remote-controlled cars?
No, the contraptions were race cars powered by the sun and the ingenuity of students from 18 universities in the United States and Canada.
The university teams werecompeting in the North American Solar Challenge for a trophy and the bragging rights to having won the world's longest solar car race.
They weren't salesmen for solar cars. In fact, experts say solar cars won't be viable for many decades to come, if ever. But the cars and last month's race showcase recent advances in technology and demonstrate the promise of solar energy in other uses.
Students and experts talk of using solar cells to assist cars, perhaps providing energy to cool off the interior on a hot day while a car is parked. They're even more excited about solar energy for homes and other buildings in regions where there's plenty of sun to go around.
Building a better mousetrapThe university teams' challenge was this: Build a race car that runs on a measly 1,000 watts — about what a hair dryer puts out — cruises at highway speeds and carries a driver 2,500 miles from Austin, Texas, to Calgary, Alberta, in western Canada.
The cars' designs varied as teams experimented with weight and aerodynamics. The Massachusetts Institute of Technology's vehicle looked like a stealth fighter jet and had three wheels instead of four to lighten the load. The University of Michigan's car had a flatter body and wheels wrapped in shells that look like catamaran hulls.
But each team shared this much: They all invested thousands of hours over many months.
“It was a logistical nightmare,” University of Michigan student Brian Ignaut says of the two years of designing and building that went into his team's car.
The payoff was being able to test engineering skills against peers while also touting solar power. Plastered with thousands of cells that collect energy from the sun, the cars turned heads wherever they went and prompted the inevitable question: When will I be able to buy one?
Probably never, was the standard answer the students gave when they showed off their wheels at several stops along the race route. A standard car with all its modern comforts, and thus power needs, would require many times more cells than could be attached to its body.
In contrast, buildings have lots more surface area on rooftops to collect electricity.
Immediate concerns include road killFor those 10 days in July, however, the students weren't concerned about future solar applications. They had immediate worries: cloudy skies that meant less electricity, crosswinds that pushed cars around and hail that dented solar cells.
The college kids christened their cars with names like Beam Machine (University of California at Berkeley) and Momentum (University of Michigan), and displayed personal touches like the kamikazi bandanas worn by the University of Minnesota crew and the fake tiger's tail attached to Auburn University's car when it was parked for display.
Teams had mechanics to fix and change car parts, computer analysts to monitor data from the cars and scouts to travel ahead to track the competition and even shovel road kill off the highway. Some teams also had weather experts to monitor conditions.
The race took its toll on two teams that had to drop out, one due to a battery fire. Four others had to be towed part of the time just to keep up with the rest of the pack.
The student drivers also had several close calls: big rigs and passenger cars coming too close, in some cases swerving as they saw the racers for the first time. Some would even drive parallel to the race cars, creating dangerous wind gusts.
Racing at 1 to 2 horsepower The vehicles are built light, about 400 to 500 pounds, because the cells can only put out between 800 to 1,500 watts of power. Exactly how much power depends on how many cells are on a car and how efficient those cells are in creating electricity. In car terms, it's about 1 to 2 horsepower.
“Think about that,” says Richard King, head of solar research at the U.S. Department of Energy, one of the race sponsors. “My passenger car has 150 horsepower and here they're using 2 horsepower to go at highway speeds.”
Some teams spent two years preparing for the race — from fundraising to buy the most powerful solar cells to designing aerodynamic car bodies that reduce drag. Team budgets ranged from $40,000 to $1.8 million per car.
George Douglas, a spokesman for the National Renewable Energy Lab, a division of the Department of Energy, calls the race a “design challenge that forces them to think of energy efficiency as the primary focus.”
It was also about competition and camaraderie in the pits and on the course. One night a University of Missouri team member walked around offering rivals chili. At the start of the last leg of the 10-day race, the University of Minnesota's team leader playfully yelled to his crew to take it easy on its closest rival, Michigan, then turned to the Michigan crew and said, “Good luck today, guys.”
Cell, battery advancesThe competition is fueled in part by the fact that solar race cars are much faster these days. Two decades ago, when the first solar races were held, students were lucky if their cars could do 35 mph. Today, they can top 80 mph, though the race kept to posted speed limits.
The reasons: more aerodynamic designs, solar cells that have doubled in efficiency and much lighter onboard electricity storage. Instead of the 400-pound lead acid batteries used a decade ago, today's cars need just 70 pounds of lithium batteries, the same kind used in laptops, cell phones and some digital cameras.
The University of Michigan, the team with the deepest pockets, ended up winning a close race, just 12 minutes ahead of the University of Minnesota.
Success came down to having the most powerful array of solar cells, a large, well-drilled support team and aerodynamic wheel wells that kept the car on course even when crosswinds pushed competitors around.
“Our car sails in the wind,” says Robert Vogt, Michigan's strategy leader.
Incentives for solarDespite the advances in technology, solar still costs about two to three times what most homeowners now pay for electricity. Even so, the price has come down by 80 percent in 25 years, says Gary Schmitz, another spokesman for the National Renewable Energy Lab.
The lab has set a goal of halving the cost further in a decade, and if the cost of electricity from fossil fuels continues to rise, Schmitz says, “we will easily reach parity in 10 years.”
Lower solar costs and higher fossil fuel prices have created renewed interest in the technology after an initial wave of support in the 1970s.
The energy bill passed by Congress last month provides a $2,000 federal tax credit for home solar systems. California is leading the way among the states with an initiative that includes homeowner rebates and requiring developers to include solar power as an option in new homes.
“I envision a solar house where the photovoltaic cells are on the roof power not only your house but your electric vehicle,” says King, the Energy Department solar expert. “That would make a wonderful second commuter family car.”
Hybrid Technologies, a company based in Las Vegas, is following that vision, helping to build a luxury home that is entirely off the power grid.
Electricity from solar cells, as well as small wind turbines camouflaged to look like chimneys, will be stored in lithium batteries. When completed in early 2006, the house and its plug-in electric vehicle will draw power from those batteries.
“We're closing the loop” for off-grid power, Hybrid Technologies spokesman Richard Griffiths said during a tour of the construction site in Calgary.
Career pathsSchmitz says solar power won't be a “silver bullet” that solves America's energy problems. But, he says, by 2050 it could meet up to half the nation's energy needs, compared with just 2 percent today.
By that time, some of the students who competed in the solar race will have built careers in the field.
Stanford's team leader is already on that road. Having just graduated, Eerik Hantsoo was hired by Nanosolar Inc., a company that makes super-thin solar panels for homes and other buildings and whose investors include the founders of Google.
“It's really shown me the potential of alternative energy,” Hantsoo says of solar racing. “Before this I thought I’d end up designing fighter jets.”
