Solar-powered vehicles have been around for over 2 decades – why is it then that we still consider this environmentally-friendly and economical mode of transport such a big deal?
Motor companies and science, technology, and engineering students continue to research and design ways in which such vehicles can be built to suit our needs. Even though competitions and races have been taking place since the late 1980s in some cases, the challenge of coming up with a car big enough to fit the family (and the shopping) while still relying mostly, if not entirely, on solar energy for power, remains a tricky question to be solved.
In order to understand the challenges of creating such vehicles, let’s look – briefly – at the technology involved. Firstly we want a vehicle that does not need excessive amounts of power to run, so to make motion along a surface easier, friction is a key factor to reduce. This is why in many cases designs involve more tricycle-looking vehicles than the standard car with 4 wheels touching the road. Wheels are also designed to be narrower for the same reason.
Weight reduction is a further key parameter, hence lightweight materials with a low density are generally selected for the skeleton, such as titanium, carbon fibre and fibreglass. Batteries are also required, used as a back-up for times when direct sunlight is not available, but regular lead acid car batteries are heavy; alternatives such as Nickel-Metal Hydride (NiMH), Nickel-Cadmium (NiCd), Lithium ion or Lithium polymer batteries are preferred. With all this in mind, the final challenge is providing space in this mini-lightweight vehicle for passengers and taking their own weight into account!
Ford recently developed a model, displayed at the Consumer Electronics Show in Las Vegas at the beginning of this year. The Solar C-MAX Solar Energi Concept (very originally named) was a product of the collaboration of Ford with Sun Power Corp and the Georgia Institute of Technology. Although such concept models are designed in full, it is more often the case that selected features are used and the model as a whole may never be built or find its way into the market.
Nevertheless, it is worth acknowledging that this model could theoretically overcome the need for plugging in, recharging solely through the collection of solar energy through panels fitted on its roof, enhanced by a special concentrator.
The type of encounter of solar energy and transportation that the general public is most acquainted with, however, is not commercial use but ‘challenges’. These competitions have popped up across the globe since the 1990s, and as you would expect, are generally set up in the sunnier regions of the world. The challenges are usually annual or biannual competitions, with the World Solar Challenge of Australia being arguably the oldest, established in 1987. Teams come from all over the world to compete for a variety of titles, corresponding with different competition ‘classes’, of which some involve travelling as far as possible, camping overnight and continuing the next day.
As with all competitions, certain ground rules are set: no more than 6m2 of solar panels are permitted per vehicle and all energy used to run the vehicle must be from the sun or from kinetic energy produced by the vehicle itself. Challenges aimed specifically at high-school students are also run, such as the Solar Car Challenge in the US, where workshops and areas for display are also part of the Solar Education Program (http://www.solarcarchallenge.org/challenge/). Another note-worthy challenge is the American Solar Challenge, involving colleges from North America, with competition names such as ‘Sunrayce’ and ‘Formula Sun Grand Prix’ for those fond of science and technology wordplay!
The ‘do-it-yourself’ version
And if neither buying fancy cars nor participating in challenges is for you, there is always the D.I.Y. option at hand. Although Germany is a pioneer concerning commercial solar-powered vehicle design and sustainable transport, it was an individual in France that decided to design and build his very own solar-panel-powered tricycle. He notes that prerequisites were EURO5,000 and electrical knowledge, claiming that without the petrol costs of a regular car, he can make that back in one year. This particular vehicle can travel a distance of 200km (with pedalling) and up to 150km using solar energy alone. Its creator claims that there are many ways in which generators can produce energy for free, but due to the role of petrol in world markets, such generators have not been commercialised. Conspiracy theory is never lacking!
So in fact, there are continual developments in designing and creating solar-powered vehicles, both as play for college students as well as for practical purposes. Hybrid cars have indeed existed for a while now, with the most common sources of energy being an internal combustion engine and an electric motor; solar-powered vehicles are looking to overcome the need for internal combustion engines at all. The ideal solar-powered vehicle would be very economical to run with solar energy freely available on sunny days and readily stored for times of need. The situation is perhaps too perfect, neglecting those regions where sunlight is scarce, but it does not detract from expecting energy-efficient, environmentally and pocket-friendly vehicles appearing for the general public in the near future!
Alexia Karageorgis has an interest in exploring human relations to environmental issues. She graduated from the University of Oxford with a Geography BA, and after several nature conservation volunteering escapades, she decided to revert back to the student life. She is currently following the Science Communication and Public Engagement MSc at the University of Edinburgh while nurturing her new interest in British Sign Language.