Presenting BYJU’S ‘What If?’ where you, the students, get to ask us your questions. It can be anything in the whole wide world but there’s just one condition: it should start with ‘What if?’ We’ll pick the most intriguing questions and feature it along with an illustrated explanation on The Learning Tree Blog.
To ask your question, fill-up the form here:
The latest question of the What If? series comes to us from Manashvi Singh of Amritsar, Punjab, who asks:
“What if the Sahara desert was covered with solar panels?”
In a time when it is crucial to find sustainable alternative sources of energy, solar power has become one of the leading contenders for a working solution. Solar panels are cheap to produce, rely on an endless supply of natural energy (the Sun) and produce practically no waste products directly. But how much solar energy would we need to power the whole world? What if we were to cover the largest desert on the planet with solar panels? Would that be enough? Would it even be possible? Let’s try and answer Manashvi’s question.
The sheer size of the Sahara desert might actually surprise you. It spans a whopping 9.2 million square kilometres. That’s thrice the total area of India! In fact, if the Sahara was a country by itself, it would be the fifth-largest in the world, ahead of Brazil and just behind China!
As you can imagine, covering the entire Sahara with solar panels would be a huge task. But assuming that we did, would it provide energy for the whole world?
According to NASA, the Sahara receives an average of 2,000 to 3,000 kilowatt-hours of solar energy per year. A kilowatt-hour (kWh) is a unit of measurement used to quantify energy. 1 kilowatt-hour is the energy consumed by a device of 1 kilowatt power in 1 hour.
Assuming we cover the entire desert with solar panels that work at 20% efficiency (this is the efficiency of common solar panels used in homes), it is estimated to produce around 2,760 trillion kWh per year. The entire planet put together needs 23,398 billion kilowatt-hours every year. Now, these are big numbers, but if you remember your number system and do some basic division, you’ll realise that the Sahara’s solar panels would produce roughly 10 times the energy needed by the world. So why haven’t scientists and engineers tried to harvest all this energy yet?
As always, when it comes to interfering with nature, things are not always that simple. Even seemingly small changes to the natural order of life, particularly in sensitive ecological regions like deserts and rainforests, can have huge side effects. Covering an entire desert with solar panels is making a major modification to nature and can have strange consequences.
Scientists believe that covering the Sahara with solar panels could increase vegetation in the area by up to 20% and even cause unexpected amounts of rainfall. Seems completely opposite to what you would expect, doesn’t it?
You see, Saharan sand is extremely light in colour, which means it tends to reflect a lot of light and heat back up into the air. If we enveloped this light sand with dark solar panels, it would mean that a majority of the sunlight and heat would be absorbed and not reflected back into the air. This would cause the ground temperature to increase. You know that warmer air rises upwards. In this case, it will head up to regions of the atmosphere where it’s cooler. The moisture there would then condense and fall as rain.
And just like that, one of the most unforgivingly dry regions on Earth would turn into a lush grassland! The impact this would have on the wildlife is hard to predict, but entire species of plants and animals, especially the ones well adapted to desert life, could go extinct, unable to cope with the sudden change in the environment!
Setting aside the risk of causing a global catastrophe and a mass extinction event, we will also have other logistical problems. Apart from the monumental task of covering 9.5 million sq km of land with solar panels, there is the big challenge of storing and also transporting all this energy to the rest of the world.
While transporting the captured solar energy to West Africa and even across the Mediterranean to Europe would not pose that big a challenge, doing the same to faraway continents like the Americas and Australia may not be that easy. With thousands of kilometres of power cables required to transport the energy, power loss during transmission would be a tough issue to tackle and the maintenance work would be a nightmare!
So there you have it! Although it would be theoretically possible to cover the Sahara with solar panels in order to harvest the world’s energy needs, the execution would perhaps raise more problems than it would solve.
Did you enjoy reading this? Check out the previous editions of the ‘What If?’ series:
Do you want to ask your own ‘What if?’ question? Fill the form below and stand a chance to be featured on the Learning Tree Blog.
Also, check out our new series Tell Me Why where we answer your questions that you’ve always wanted to ask but never could!
Suraj Prabhu is a self-proclaimed audiophile and a jack-of-all-trades writer with a diverse set of interests. An amateur quizzer on the side, he claims that the first object he fell in love with was a book on flags at age 3. His favourite punctuation mark is the 'Oxford comma,' which coincidentally happens to be one of his favourite songs too!
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