Solar energy grasped a considerable amount of attention in the automobile industry a few years ago when Toyota announced its willingness to develop a 100% solar-powered car. Soon after, a solar panel was offered as an option on the 2010 Prius model. Since then, however, talks about the development of that revolutionary solar car have been rare, if not absent. What exactly is happening with solar R&D?
Breaking the market
Technically, a solar car uses photovoltaic (PV) cells to transform sunlight into electricity which powers an electric engine thus enabling the car to move. This emission-free type of power is obviously unlimited, even more so in countries where the sun shines almost every day. The problem, however, is that transforming sunlight into enough electricity to efficiently propel a car is not an easy task.
One of the main challenges solar-powered cars’ developers face is to build a battery that can store enough energy to propel the car. With current technology, such a battery would need to be very big and heavy if it were to supply modern-day cars since they generally are conceived to fit a whole family. Unfortunately, weight is the enemy of solar cars: the more the car weighs, the more energy is needed to propel it. Another conception challenge actually lies in that very fact.
In effect, PV cells can still convert only about 30% of the sunlight they receive into electricity. In other words, for an electric motor powered by sunlight to completely shift the weight of the battery, the car itself and the people in it, every single inch of the car’s surface would need to be covered with PV cells. This is the main reason why the current solar vehicles that exist tend to be designed for a single passenger… and the reason why Toyota has only been able to offer a solar powered ventilation system on its Prius.
In fact, providing solar power for more features than the Prius’ ventilation system would either require a lot more cells, or a major technological breakthrough. In other words, lighter batteries and cars as well as more efficient PV cells are likely to be needed if developers wish to see sunlight actually move a modern-day car (same size, same functions, same comfort, etc.) from point A to point B.
Toyota’s solar panel is not to be looked down on, however. As an option, the Prius’ rooftop covered with PV cells allows a special emission-free ventilation system to work. In fact, one can actually park his or her car in the sun and avoid the usual greenhouse effect that warms up the inside of the car; instead, the sun will activate a ventilation system inside the cabin, thereby allowing the captive air to circulate and to maintain a temperature close to that of the outside. Although this option is quite costly, it must be convenient especially during the warm summer days when getting in your car feels like entering a poultry roaster.
Toyota, however, is not the only car maker working on solar energy. Hyundai, for instance, designed a prototype solar-powered car in collaboration with a postgraduate student at the MIT. The 2020 Hyundai City Family Car functions like a plant: it mostly needs sunlight and water. Its outer, transparent solar panels collect ambient light to produce the electricity that allows the central tank’s water to split into oxygen and hydrogen, the latter powering the car.
Although the prototype has not led to an actual car yet, the technologies it uses are a good omen: its artificial photosynthesis and its solar concentrator could bring solutions to some of the serious problems that solar-powered car development currently faces. Who knows, maybe a few years from now we will all be yearning for the solar-powered, high-tech version of the great, affordable Hyundai Elantra 2013?
Solar-powered car R&D may not currently be filling newspapers with stories of remarkable technological advances, but just like reliable hybrid cars have taken decades to design and are still evolving, solar-powered cars could very well materialize in the future. Actually, has the Solartaxi project not already given us some tangible proof that the best is yet to come?
About the author:
Alexandre Duval is a freelance blogger writing about cars, insurance and other topics of interest. He is also currently completing his master’s degree in political science at the University of Quebec in Montreal.