The amount of solar energy received by Earth could power a civilization over 100 times larger than ours!

Or at least that’s the information planetary leader Elon Musk has retweeted, originally published by Twitter account @Rainmaker1973, a verified account with more than one million followers. It reportedly didn’t make Twitter employees cry this time.

This affirmation comes from a thought experiment, claiming that if just 1% of the solar energy that was retrieved from the Sahara via conventional solar panels, it could power the entire world.

The math goes like this: according to some estimates, the world energy consumption is 17.3 Terawatts of continuous power for an entire year. Then, if you cover an area of 208 square miles, it can provide 17.4 Terawatts of power. It takes into account solar panels currently available for roofs, with moderate efficiency.

The Sahara has more than the room for that, since it’s about 5.7 million square miles, and receives sunlight more than twelve hours per day, making the desert a prime location for solar energy harvesting. Even though this would be unarguably costly at about five trillion dollars, this is less than Obama’s bailouts in 2009. 

Let’s take a look at what Musk proposes, then.

• A civilization 100 times larger than ours would need 17.3 TW x 100. That is, 1,730 TW.
• According to the original tweet, just 1% of the Sahara would power the Earth. That means, 100% of the Sahara would be able to power the energy of a civilization 100 times larger than ours. The Earth, as Musk surely knows, is much larger than the Sahara.
• Elon Musk is right in saying that the whole Earth could power a civilization over 100 times larger than ours but leaves us wondering exactly how large, considering the whole Earth.

Even though he didn’t bother to delve into the issue further, he makes a valid point worth exploring. Can the current energy crisis the world is facing be solved by solar energy? As it turns out, there are a couple of issues with this concept.

First of all, solar panels have a certain longevity. Typical panels, much like the ones used in the thought experiment, last only 25 to 30 years. Bear in mind this is an average, and climatic conditions can affect them sooner. It’s anyone’s guess how much money would go into maintenance alone, not even to mention the replacement costs every two decades or so.

Besides that, you can’t transport energy from the Sahara to, say, Siberia, without any losses. A typical maximum transmission distance is about 300 miles. To achieve this, the typical voltages for energy transmission go between 155,000 to 765,000 volts. That’s a huge amount of volts! You need to build electric substations for this, which, as you can imagine, are costly.

All this means that while solar energy is a promising source, more technological innovations are necessary to achieve something like what Musk envisions. While there are ideas to solve the issues presented before, we’re still not there.

Luckily for us humans, if we’re subjugated and need to slave away our energy to our 100-times-larger-civilization alien overlords, the Sahara would suffice. The problem comes with civilizations over 100 times larger. Perhaps if it’s just a bit over 100, Musk can contribute with his assets to fill the gap.

The amount of solar energy received by Earth could power a civilization over 100 times larger than ours!