Solar cars are the dream solution to growing automotive emission concerns worldwide. In developed and developing nations, pollution from internal combustion engines is a growing concern for air quality and impact on climate change.
Electric and hybrid cars are growing in popularity due to their reduced dependency on fossil fuels, or total elimination of their demand for gasoline or diesel fuels. Unfortunately, today’s electric cars still require batteries that must be recharged, relying on availability of charging stations or connectivity to utility power when not in use.
Solar cars are a better solution for use by the masses, and progress is continuously being made in producing a solar car for commercial use. One of the major concerns that must be conquered before solar cars are practical for daily use by consumers is mileage.
Solar Car Efficiency – Not There Yet
Solar car mileage has been steadily improving in prototypes built by engineering teams and developers of solar race cars. Teams at various universities and manufacturers around the world have focused on designing and building solar cars that are energy-efficient and capable of traveling at higher speeds and longer distances.
India – Manipal Institute of Technology
A team working at India’s Manipal Institute of Technology has developed an all-solar car intended to seat four passengers in comfort, with improved safety features and better performance. This SolarMobil team estimates the vehicle will have a range of 160km (nearly 100 miles), an impressive accomplishment.
With zero emissions, respectable cruising range, and a top speed of approximately 55mph, this vehicle named the SM S1 could well be the solution to the tremendous pollution that is plaguing Indian citizens and causing serious health concerns.
China – Hanergy
In China, automotive manufacturer Hanergy has developed a prototype that utilizes lithium-ion batteries to power the vehicle when sunlight is not available. Their efforts have produced a vehicle with a range of approximately 50 miles when utilizing strictly solar power, based on 5-6 hours of charging from the sun. With fully-charged batteries, the maximum range is expected to be 217 miles.
Compared to battery-powered electric cars’ miles per charge that currently tops out at an estimated 335 miles, solar cars begin to appear as a more attractive and viable alternative.
US – University of Michigan
University of Michigan’s Solar Car Team has a long history of designing, building, and racing solar cars nationally and in international competition. Through their commitment and efforts, solar car efficiency has improved significantly.
Just how efficient is a solar car? This UM team has taken steps to improve efficiency in their latest effort for racing – the Novum solar car, incorporating gallium solar panels in its construction.
Photovoltaic cells that provide power in silicon-based solar panels are typically rated at 20% efficiency, but with advances in gallium panel technology that incorporate thinner, higher-power panels, these are reported to operate at 35% efficiency. While more expensive to manufacture, gallium panels also require less space, and add less weight to the vehicle.
Netherlands – Eindhoven University of Technology
Another significant contribution to solar car gains in mileage comes from this team in the Netherlands. They have built and continue to refine a four-seat solar vehicle known as the Stella Lux, weighing in at only 826 pounds, with a range of 600+ miles when fully charged.
Stella is aerodynamically advanced with a gap/tunnel down the center of the vehicle that gives it the appearance of a catamaran ship, but the intention is to lower wind resistance and reduce the energy required to propel the vehicle.
How Efficient Is a Solar Car?
Although most solar cars are still rated in the 20-35% efficiency range – based on today’s readily-available solar technology, some engineers and manufacturers have been able to develop vehicles reaching a level as high as 42% efficiency.
This is primarily a matter of how much electrical energy can be produced by the solar cells, generating power to charge the batteries that in turn power the electric motor.
Speed and range are products of several factors:
- Aerodynamic properties of the vehicle – steps taken to reduce wind resistance and drag.
- Weight – utilization of the lightest materials available, while still providing strength – this must include consideration for weight of the storage batteries
- Size/shape – most solar cars built for racing and prototypes include wide or long body styles to accommodate solar arrays. Low height and flat surfaces also contribute to additional surfaces for mounting panels, while reducing resistance.
Solar Car Mileage Continues to Climb
As manufacturers, scientists, and collegiate teams provide ingenuity and improved technology to build faster and more efficient solar vehicles, their use in consumer markets will become more practical.
Solar cars that reach highway speeds with a range that competes with or exceeds that of all-electric vehicles will certainly succeed in the global market for zero-emission automobiles.