Why are there no solar powered cars?

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There are projects that tried, learned and remained in history. Others continue to struggle with the most diverse difficulties, such as Lightyear, and imply that there is no success in solar-powered cars. Why?

Well, we have to separate two categories: conventional cars that receive these cells and cars dedicated exclusively to testing the concept that solar energy can power a vehicle.

Having said that, we must say that solar cars exist. The best place to see them is the World Solar Challenge, a race held every two years in Australia. Competitors have to travel around 3000 kilometers, from Darwin, on the north coast of the country, to Adelaide, on the south coast, using only the Sun’s energy.

Many of the cars competing in this race look more like amusement park or science fiction vehicles than cars seen on the road. In a very interesting article by The Convertionwe understand more clearly why solar cars are not an option for everyday travel, at least for now.

Collect enough sunlight

There are some calculations that indicate that on average the Earth receives about 1361 watts of solar energy per square meter in the upper layer of the atmosphere, a value known as the solar constant. Therefore, our planet receives a lot of sunlight on Earth during the day. However, light scatters as it passes through the atmosphere, so the amount that reaches a given surface is greatly reduced.

As such, the average is calculated over an entire year (to eliminate the effects of different seasons) our planet receives about 342 watts per square meter. This is approximately enough power to run a normal refrigerator.

However, a normal car doesn’t have enough surface to collect much solar energy. The sizes of these cars vary greatly, but a normal-sized car in the US is about 5 meters long by 2 meters wide, so it has about 9 to 10 square meters of horizontal surface.

Large solar farms that send electricity to cities and towns compensate for the fact that sunlight spreads over such a large area by placing millions of solar panels across thousands of hectares. Some, especially in desert areas, use fields of mirrors to concentrate the Sun’s energy. But a normal car does not have enough surface to collect much solar energy.

Transform sunlight into energy

Another problem is that the Current solar panels are not very efficient at converting sunlight into electricity. Normally, their efficiency is around 20%, which means that they convert around a fifth of the solar energy that reaches them into electrical current.

This means that 3420 watts of solar energy falling on an average car covered in solar panels would only produce 684 watts that the car could use. In comparison, it takes around 20,000 watts for an electric vehicle to travel at 100 kilometers per hour.

Vehicles competing in the World Solar Challenge tend to be large and have designs that maximize their horizontal surface area. This helps them collect as much sunlight as possible. As a concept vehicle, this is good, but most models don’t have many windows, nor room for anything except the driver.

When the sun doesn’t shine

Another challenge is that geographic location, daylight hours and weather conditions affect the amount of solar energy that can be produced.

The Earth is tilted on its axis, so not all areas receive equal amounts of sunlight at any given time. When the Northern Hemisphere tilts toward the Sun, the upper part of the globe receives more sun exposure and sees spring and summer, while the Southern Hemisphere is cooler and darker. When the southern half of the planet tilts toward the Sun, areas in the southern half of the Earth receive more Sun and the upper half receives less.

Areas close to the equator receive constant sunlight throughout the year, so areas closer to the equator – such as Southern California or the Sahara Desert – have more intense solar energy than places closer to the Earth’s poles. , like Alaska.

Solar cars would also have difficulty collecting enough sunlight on cloudy or rainy days. Even large utility companies with huge solar farms have to plan for periods when the sun isn’t shining.

However, drivers need their cars operational day and night. Therefore, for a solar car to run after dark, it would have to use the extra energy it collected during the day and stored in a battery. You Solar panels and batteries increase the weight of the carand heavier cars need more energy to run.

Researchers are working to design solar cars that are more suitable for everyday use. For this to happen, designers will have to make solar panels more efficient at converting sunlight into energy and design solar panels better suited to cars. It will also be critical to make solar car systems cheaper so that average buyers can afford them.

For now, the closest option to a solar car is an electric vehicle that is charged at home or at a charging station. Depending on how electricity is produced, some of the energy that powers these cars likely comes from solar panels, wind turbines, hydroelectric dams or other renewable sources. And that percentage will increase as states strive to shift to clean energy in the coming decades. If you are driving or riding in an electric car, you may be traveling on solar power right now.