The fast moving world of solar energy
Solar-powered cars compete in the Darwin to Adelaide race, Australia Photo: World Solar Challenge
Since the invention of automobiles there has been car racing, from racing classic cars around the Milwaukee mile in the 1900s, to the world-famous F1 races of today that feature gas-guzzling miniscule race cars serving no purpose other than driving around in circles really fast. With global warming an ever-increasing concern, what are our alternatives to these fuel-hungry speedsters?
Enter the World Solar Challenge, a 3000km solar-powered car race across Australia. This week the biannual race was won, for the fourth time, by a Dutch team from Delft University of Technology who completed the race in 33hrs 3mins, with an average speed of 90.71km/h (75mph). A careful balance between maximising solar panel surface area, and keeping a sleek, drag-resistant shape played a role in the winning team’s success.
There are two main types of solar technology: dye-sensitised and excitonic solar panels. Dye-sensitised solar panels feature the trendy nanoparticle titanium dioxide (TiO2), which is used in self-cleaning glass, sun creams and even toothpaste. Titanium dioxide is white and reflects visible light, a good feature when used in sun creams but problematic when it comes to solar panels. The nanoparticles have to be dyed before they can be used, with a lot of research being done to see which dye absorbs the most light.
When a photon is absorbed by the dye-sensitised solar cell, a dye molecule loses an electron to the titanium nanoparticle, leaving behind a positive charge which moves to another part of the solar cell. With the negatively-charged nanoparticle and the positive charge separated, there is a difference in electrical potential across the cell, which leads to electricity.
When a photon is absorbed by an excitonic solar cell, an electron is excited to higher energy, leaving behind a positively-charged ‘hole’. When the negatively-charged electron is initially excited, it is bound to the positive hole, as opposite charges attract. In the solar cell, the pair are separated by two special materials that force the electron and hole to move to different ends of the cell. The separation of charges, again, creates an electric potential and current flows.
Solar power is a clean, renewable source of energy to power cars for racing and normal life; the same group who designed the winning car have also designed a solar-powered family vehicle. Maybe the 70mph solar car race is less exciting than F1, but these cars are ethical and aesthetically pleasing. With increasing concern over depleting fossil fuels and rising greenhouse gasses, solar cars are certainly something to think about.
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