1991 American Tour de Sol Robert Wills The five day 1991 American Tour de Sol Solar/Electric car race started at Rockefeller Plaza in Albany, New York, on May 20. Governor Mario Cuomo said, "Energy and environment are a single concern. ...When we learn to use energy wisely we will reduce pollution, and cure acid rain and global warming". He then sent the twenty-six entrants on their way with a wave of an Earth Flag. The Route The race travelled east from Albany to Plymouth Rock, MA. The first Tour de Sol Earthfair was held this year at Plymouth. The cars took five days to travel the 247 road miles of the race. The average run of 50 miles per day emulates typical commuting and is within the reach of teams with limited technical and financial resources. In addition, cars can run optional laps each day to demonstrate their range. The winning commuter car, Solectria Corporation's Flash, travelled an extra 108 miles in laps, averaging 71 miles per day. About the Tour de Sol The 1989 American Tour de Sol was the first multi-day solar car race in the U.S.A. The Tour de Sol differs from races. Its main aim is to promote solar and electric commuter vehicles. Solar racing cars do serve a purpose Ð they push the limits of technology and pose very different design and racing problems. The main aim of the American Tour de Sol is to bring solar and electric vehicles into widespread, everyday use. Another purpose of the race is to promote renewable sources of energy. An electric vehicle still pollutes (albeit less than internal combustion vehicles) if its source of energy is a conventional power plant. The answer is to use renewable sources of energy - wind, hydro, and photovoltaics. It is not practical to carry a PV array on a commuter car that is large enough to provide a full daily charge, but efficient vehicles can gain 10 to 30 miles in range from vehicle mounted photovoltaics. We see the long term solution as having some photovoltaics on vehicles, but getting most of our power from grid-connected distributed PV on roofs nationwide. Photovoltaics on a car do serve three purposes Ð they show that PVs are a viable, available technology; they provide some measure of additional range, and especially with lead-acid batteries, they provide a slow topping up charge that can greatly extend battery life. The third aim of the Tour de Sol is education. Thousands of people come to see the cars, and millions learn of them through mass media. They learn alternatives to gasoline powered cars and fossil fueled power plants. The people who make the cars also learn a lot - building a solar car is a demanding, real-world project. Tour de Sol Car Categories Commuter Vehicles have to carry a driver and passenger and are allowed a maximum of 720 Watts peak of photovoltaics and 7.2 kWh of battery storage. The are allowed to recharge their batteries fully from the power grid each night, to emulate normal commuter use. Vehicle mounted photovoltaics are optional - it is possible to run a pure electric vehicle in the race. There are two categories of racing vehicles: Tour de Sol Racers are limited to 480 Watts peak of PV array and 4.8 kWh of battery storage. Cross-continental Racers are built to the rules of the cross-Australia World Solar Challenge and are limited only by a maximum PV area of 12 square meters. Both racing categories must travel each day using only power generated from their PV arrays. (They are allowed to start the race with full batteries though). The Open category is for any other vehicle conforming to the aims of the event. These range from production electric vehicles with more battery storage than the commuter category allows, to PV powered mountain bikes and mopeds. Notable Vehicles There were two basic types of commuter vehicles entered. Some were converted gasoline cars such as Solectria's Force and Force GT (originally Chevy Geos) and New Hampshire Technical Institute's Sungo (based on a Yugo). New England Institute of Technology's Solar Tech is a converted BMW Izetta. Mattatuck Community College's Sunbird is a beautifully converted 1952 vintage MG replica. Others are build from the ground up for lightness, aerodynamics and efficiency. The winning car, Solectria's Flash has a fiberglass frame with a fiberglass/kevlar skin and weighs only 1000 pounds with driver. In the racing categories, MIT's winning entry, MIT V, is the epitome of lightness and aerodynamic design. Dartmouth's new Sunvox IV featured an aluminum frame with a fiberglass body and composite front suspension members. Conval High school (Peterborough, NH) again entered their four wheeled Sol Survivor with its kevlar monocoque body. In the cross-continental category, Rochester Institute of Technology's Spirit with an aluminum frame and foam/dacron skin came in first. The open category had many interesting cars ranging from Solar Car Corporation's beautifully converted Ford Festiva's, to the Rosebud team's solar electric mountain bike. The winning car in the open category was the Electric Hilltopper from St. Johnsbury Academy, Vermont. Their converted 1979 VW Rabbit ran a perfect race and demonstrated a range of one hundred miles on the last day. A great performance by a highschool team. The total cost of their vehicle was $4,000. Technology Most commuter cars used 10 to 20 Horsepower series motors made by Prestolite, Advanced DC motors or General Electric with Curtis PMC controllers. Exceptions were the Solectria cars, the Sungo and the Solar Tech which used 11 horsepower Solectria brushless dc motors. There is an interesting tradeoff between the simplicity of dc brush motors and the efficiency and lightness of brushless motors as the the brushless controllers are much more complicated and expensive. On the whole, the reliability of the electric drive systems was excellent. Racing category cars, going all out for performance, generally used brushless dc motors from Solectria, Uniq Mobility or General Electric. Most of the converted commuter vehicles kept a gear box in the drive train from motor to wheels. Notable exceptions were the Solectria cars and NHTI's Sungo which has two Solectria motors connected via chain drives to each rear wheel. All of the racing vehicles used a direct drive, taking advantage of the wide torque range of their electric motors. Batteries are well known as the limiting factor in electric vehicle performance. Most cars in the Tour de Sol used deep cycle lead acid batteries made by Trojan, Keystone or Sears. The winning commuter, Solectria's Flash used SAFT nicad cells while NHTI's Sungo had Hoppecke fiber nicads. The racing category cars either used lead acid cells, or if budgets allowed, super light-weight silver-zinc and silver-cadmium cells. The use of silver based batteries is rather controversial too expensive for large scale electric vehicle production. For this reason, silver batteries may not be allowed in future Tour de Sol races. Photovoltaic modules on cars ranged from the carefully integrated Photocomm/Kyocera laminates on the Solar Car Corporation cars to the many cars using Solectria/Siemens laminates which are made in Switzerland, to the Solarex SX30s on the Sungo, to the cell by cell arrays formed to the curves of the cross-continental racers. Vehicle Testing A full day of testing was done on the Sunday before the race. As vehicle safety is paramount, no vehicle can compete in the Tour de Sol without it. Vehicles were tested for compliance with the rules, especially PV array and battery bank size. The mechanical inspection is for practicality, safety and stability and includes a cone test and starting on an incline. The braking test is stringent (better than -5 m/s2 for a four wheel vehicle) as all vehicles are carrying a considerable load of batteries. An acceleration test was done to determine pole position. All vehicles must be street legal, registered, insured and capable of sustained speeds of 25 mph or more. Probably the most interesting testing that was done was vehicle efficiency. By measuring average battery voltage and current over a known course, we could calculate the average Watt-hours per mile used. A very simple clip-on instrumentation system was used Ð one Fluke 87 meter measuring voltage and another, via a Fluke 80i-1010 dc clamp probe, the current. The fluke meters can calculate true average values over a period of up to 36 hours. The results of the test (see table) show excellent consistency by vehicle type: Most of the racers ranged from 47 to 58 Wh/mile, commuters typically around 160 to 200 Wh/mile and the heavier open category cars ranging from 230 to 260 Wh/mile. Cars that deviated dramatically from these numbers either had errors in measurement, or drove with a very different style to others in the test. In particular, the low energy usage of the Force GT can be attributed to careful driving and the use of regenerative braking. Results Placings of the 26 entrants are shown in the table. Scoring for the American Tour de Sol uses "adjusted time". This is the route running time minus an allowance for each optional lap, plus any time penalties incurred for rule infractions or not completing a leg. Winning teams received cash prizes and trophies. The top three student teams in the commuter and open categories shared $10,000 in prize money provided by the U.S. Department of Energy, our major sponsor. There are also DOE prizes for the best student videos of the race. Other sponsors included the New Hampshire Governor's Energy Office, the New York State Energy Office, the New England Electric System and the Nathan Cummings Foundation. A Major Step towards Sustainability The American Tour de Sol is organized by the Northeast Sustainable Energy Association (NESEA) which is based in Greenfield, MA. Just last year we changed our name from Solar Energy to Sustainable Energy to better reflect the aims of the association. The use of solar energy is just one facet of a sustainable future. It seems that a new environmental disaster emerges every year. First there was acid rain, then global warming, then air pollution in cities, gasoline in groundwater, ozone depletion, and now oil wells burning in the middle east. All of these are caused in part by automobiles. In addition, oil reserves are dwindling, and will not last more than another generation. The oil age has lasted just 100 years and is ending in environmental disaster. We need sustainable energy technologies that last not 100 but 1000 years Ð or even 1000 generations Ð without harming the environment. Harry Braun's book "The Phoenix Project" is a good overview of sustainable energy options. He concludes that solar energy is the only viable alternative. In the broader picture, we need sustainability in energy, transportation, resource use, and agriculture - a sustainable society. Electric vehicles offer a step beyond the frustration of being able to do little more than recycling paper and containers. Put PVs on your roof and an EV in your garage, and you have taken a major step towards living in a sustainable society. ATdS Symposium & the 1992 Race The Tour de Sol Symposium will be in Boxboro, MA, (just west of Boston) this October 26 & 27, and will feature displays of commuter and racing solar/electric vehicles, and sessions on vehicle design, components, policy and economics. The keynote speaker will be Robert Stempel, CEO of General Motors Corporation. The car display will be open to the public. Planning of the 1992 race is now under way. We expect more cars, more publicity, and an even better time for the participants. As always, we are looking for the support and volunteers that make these events possible. If you would like to help with the Tour de Sol, please contact the NESEA office at the address below. Access: American Tour de Sol, Northeast Sustainable Energy Association, 23 Ames St, Greenfield, MA 01301 ¥ 413-774-6051 The Phoenix Project, Research Analysts 1990, POB 62892, Phoenix, AZ 85082 ¥ 602-969-3777.