|Fig. 1: Tesla car battery. (Source: Wikimedia Commons)|
Humans have been using fossil fuels for hundreds of years but many fail to consider what would happen when the world runs out of them. Ever since the Industrial Revolution, the extraction of fossil fuels has increased tremendously, leading to the over-use of these precious resources. This careless use of fuel is not only depleting the valuable resources, but it is also seriously impacting the climate. How will the world survive without fossil fuels, especially oil, which we rely on so heavily in our everyday lives to commute?
Currently, the world consumes over 13 billion TOE (1 TOE = 1 tonne of oil equivalent = 4.187 × 1010 joules) per year and it is the most used fossil fuel in the world.  If we continue with this trend, our known oil deposits will only last us a few decades. Although it is true that we might discover some new oil deposits, which could save us some time, the rate at which we consume oil is not constant. As the worlds population increases rapidly and as more countries develop and evolve, the use of oil goes up and therefore, our oil reserves will run out earlier than predicted. The world needs to find a solution to this growing problem before its too late. One way to mitigate this concern is to revolutionize the way people travel and commute by using solar panels to help power cars.
Although it seems very unlikely that a full solar powered car could be made in the near future, semi-solar powered cars are a good start to preserving precious resources. Just relying partly on solar power to run cars could make a significant reduction over time in the use of fossil fuels. The reason fully solar powered cars are not possible is because of the amount of surface area for solar panels needed to provide enough power to the car and the current efficiency of the solar panels.Suppose we have a car with a combined area of four square meters on the roof. Given that the direct sunlight at Earth's surface is about 1000 watts per square meter, on a good day, about 3,200 Watts of solar power will shine on the roof around noontime. If the solar panel is 100% efficient, all 3,200 Watts could be used to power the car. To put this in perspective, a small car has an 20hp engine (1 hp = 746 W) meaning it would take about 14,920 Watts to power this small car. Clearly, solar panels can not fully power a car on its own, but it can definitely help charge the car battery for AC use, extra mileage, and other controls in the car powered by the battery. Although this might seem small, it will decrease fossil fuel use in the future and as Solar panels get more efficient, more and more energy could be used to power the cars and will lead to even less use of fossil fuels. This is a great way to work towards saving these nonrenewable resources.
Solar powered cars use solar panels with photovoltaic cells that convert the suns energy to electricity. The process of making electricity begins when the silicon atoms absorb some light. The light gets absorbed, and one of the electrons that's in one of the bonds gets excited up to a higher energy level and can move around more freely than when it was bound. That electron can then move around the crystal freely, and we can get a current. This electric current can leave the cell through the metal contacts and be used.  The solar panels are placed on the roof of the cars and will be used to supply energy to the car battery as shown in Fig. 1. The solar panels will recharge the battery in the car over time. There are an abundant amount of benefits that come with these solar powered cars. The first benefit is that it does not harm the environment. They do not create greenhouse gases or even add to the noise pollution because solar panels work silently. This may be the start to a solution for the exponentially growing use of our precious fossil fuels problem. As if semi-solar powered cars were not good enough already, they also use energy that is free and widely available.
No manufacturers have mass-produced full solar sedans yet, but it is clear that they are working toward implementing solar energy into cars. An example to show how close we are to creating the cars of the future is the 2010 Prius, which has a solar-powered cooling system. The ventilation functions separately from the motor and keeps the car cooled even when it is off and parked.  These projects have shown the viability of solar energy with transportation.  Although the amount of energy produced by solar panels on cars is not large at the moment, as the cells become more and more efficient over time, we could implement significantly more energy into powering the cars. This will lead to the world slowly relying more on solar energy rather than the harmful fossil fuels we currently rely on so greatly. We are certainly heading in the right direction to a cleaner, healthier, and less destructive life.
© Martina Sly. The author warrants that the work is the author's own and that Stanford University provided no input other than typesetting and referencing guidelines. The author grants permission to copy, distribute and display this work in unaltered form, with attribution to the author, for noncommercial purposes only. All other rights, including commercial rights, are reserved to the author.
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 B. Nally, "The Future of Cars Could be Solar," Renewable Energy World, 2 May 16.