Why Don’t We Cover the Sahara In Solar Panels?
So, you want to be a responsible human and have a carbon-neutral life? You have got your EV, vegan diet and recycled clothes, great! But what about the electricity that powers our modern life? We could use wind, but it doesn’t always blow, and the same can be said for solar on overcast days. But what if we covered a desert in solar panels? Somewhere where it rarely has a cloud in sight. Would this be the guilt-free ultimate power source for a sustainable humanity?
As always, it depends.
To provide enough solar to power the entire world, it would take 51.4 billion 350W solar panels, which would take up an area the size of 115,625 square miles. This may sound like a lot, but it is only 3.27% of the USA or just a smidge smaller than New Mexico. Still a vast area, but we need to put all that solar somewhere sunny. The Sahara seems like the best bet. It is a desert, and on the equator, so lots of sun with barely a cloud in sight! As the Sahra is 3.6 million square miles in size, our giant solar farm would only take-up 3.25% of it.
This sounds promising. A dessert shrinking by 3.25% is nothing in the grand scheme of things. If set up correctly, few animals or humans will be displaced, and you don’t need to do any deforesting or robbing plants of their precious sunlight. Plus, the numbers here are for a solar farm in North Carolina where it is less sunny than the equator, so our 51.4 billion solar panels will make more power in the Sahara. We have overcompensated, and still, it seems feasible!
By feasible, I mean possible. This is a massive project, and the costs are astronomical!
A 350 W solar panels costs between $210-$450 to install on your home. To install it in a dessert will cost more. You have to build stands for the panels, transport them to the middle of nowhere and provide a new electric infrastructure over dunes and rocky ground. Let’s take a rough estimate at the cost for putting these in the Sahara and say $450 for panel and delivery, $300 for infrastructure and $250 for stand and installation. That's $1,000 per panel at bulk pricing.
Our solar farm would cost 514 trillion dollars or roughly 23 times the size of the US economy. Even if my estimate for solar panel cost is off, this shows the vast expense of such a monstrous project and possibly why no-one has done it yet.
So, cost might be a huge problem, but that is beside the point. We are trying to save the world and are blue-sky thinking here! What if we had unlimited money? Should we still do this?
Even if we can build this, we still need to get this power all across the globe. Plus, countries like Australia will want power even when the Sahara is in darkness. Both of these problems are relatively easy to solve.
We need a massive battery pack to store the energy made during the day to power the farm’s output during the night. We could build such a battery pack underneath the solar panels, helping us not use any more space. Each solar panel has its own small battery keeping its power output even during the whole day and night. Adding these batteries involves a considerable increase in cost, so our previous 514 trillion dollar budget has been completely smashed!
We would need to add roughly 4.2kWh of battery storage to each panel (12hrs of 350W output). This would increase each panel's cost by approximately $900. That would nearly double the overall cost! But we have an unlimited budget so let’s do it anyway!
So, now we have 51.4 billion solar panels and a 215.9 billion kWh (215.9 TWh) battery. I wonder how much carbon footprint went into making this… Let’s not think about that just yet; we need to get the power out of the Sahara first.
So, does it make sense to run a power cable from the Sahara to somewhere like Syndey? That's around 9,000 miles.
Currently, the longest power line stands at 1,580 miles. It utilises very high voltage to limit the amount of electrical resistance. Basically, more voltage means less resistance, which means less power lost per mile of cable. The upper limit of powerline loss is around 4%, any higher, and things don’t make economic sense any more, so we can assume that this long powerline losses around 4% of power or a little more. If we extrapolate out to our 9,000 miles, we will incur a power loss of 22.8%!
That is too much energy to lose. We would need to increase our solar farm's size to make up for these dramatic losses, and at $2,000 per solar panel and battery, it could get very expensive!
This is an incredibly crude way of calculating the losses in such a power line, and I apologise to all my electrical engineer readers. In reality, a better solution is out there. However, it shows that you don’t want to be too far away from your power source. Countries like Australia are far better off building their own mega solar farms to power themselves, rather than incur these power losses, especially as they have their own huge desert.
But you get the picture? Storing and transporting power across the world won’t be efficient. But we have unlimited money baby! Let's splash out and spend the money, it won’t be efficient, but it will save the planet! Right?
Yeah, about being climate-friendly, you might want to hold your horses on that because our dream project has some rather huge impacts other than taking a bit of the desert.
These solar panels will change weather patterns over the whole Sahara, which will have a global effect. See, the Sahara is a perfect atmosphere heater, which is half the reason it is a desert. As soon as you start collecting the sunlight and turning it into electricity, you effectively cool the desert down. This means that rains can return to the area, allowing plants to grow again. This has a knock-on effect, and slowly the desert will turn greener and greener as the plants cool the desert just like the solar panels did, causing a snowball effect of vegetation.
This may sound great, more vegetation! But weirdly, lots of our larger, more complex ecosystems depend on the Sahara being a barren desert. The Amazon is fertilised by dust blown over the Atlantic from the Sahara, and the Sarahan heat drives its constant rainfall my mediating Atlantic winds. If you take away the atmospheric dust and cool down the Sahara, you may cause the Amazon to collapse!
The Atlantic is also fertilised by Saharan dust. Its nutrient-rich sand powers enormous algal blooms. These bloom events produce a lot of the Globe’s oxygen, so it is possible we could see oxygen levels drop too!
What's more, the weather cycles known as the Nino and El Nino events will become more frequent and harsher, meaning more cyclone and hurricanes. This would devastate Human populations up and down the Americas! Imagine a Hurricane Katrina every few years; that's how damaging it would be.
However, the most shocking effect is an increase in surface temperature, which seems so counter-intuitive!
See, water vapour (clouds) is a powerful greenhouse gas, far better than CO². While the rainfall over equatorial regions such as the Amazon will fall, the Sahara's greening will cause the rest of the world to become wetter, with more clouds. This will trap in heat, warming the globe.
But a warming Globe would cause icecap loss, which would disrupt the ocean currents, in turn causing a colossal biodiversity crash worldwide. The failing fish stocks from this would cause rampant famines across the world. Methane and CO² trapped in Arctic sea ice would be released, causing a huge run-away climate change, and a mass extinction would be set in motion, with humans being a possible victim.
So, if you want to fight climate change, it is essential to realise that we live on one Earth. Each ecosystem is connected in a global web; none of them are isolated. If you start messing with one of them, it will cause a domino effect across the others. Concentrating our global impact in one place is akin to pulling out a Jenga block from the bottom, i.e. not a good idea. Instead, we need to tactically decide where to take our energy from to minimise the global effect. Like testing blocks in the tower to see which are already loose, so that when we yank them out, it doesn’t all come tumbling down.
There is one last reason you might not want to do this, even if I haven't already put you off the idea. While the Sahara seems like a vast open wilderness available for taking, it isn’t. This land is taken, African people and its’ governments own its’ resources. Europeans, Americans and Asians have all at some point in history pillaged Africa for its’ resources, whether mineral, slavery or land. I don’t need to say much more other than we can’t let such barbaric behaviour happen again. African countries have a right to this land and its’ energy; the rest of the world has no place in trying to take it away from them without co-operation and fair payment.
That is where it gets tricky. Countries like Libya and Eygpt who own a lot of the Saharan land, don’t have stable enough governments for such international projects. Would you spend hundreds of trillions of dollars on a project that could be wiped out by a government failing or taking the land back from beneath your feet?
So, should we build a world-powering solar farm in the Sahara?
Hell no! It is a terrible idea!
But, there is something beautiful hidden here. We can power the whole world with a relatively small amount of solar panels. The Earth has 57.27 million square miles of land, we only need to convert 0.2% of it to solar, and we can power ourselves entirely. To give some perspective, it is estimated that 1% of land is built up and human-occupied (cities and towns not farmland). In other words, if we can convert 20% of urban areas around the globe to have solar on them, then we can fully power ourselves!
The Sahara isn’t our answer; our cities, towns and roads are. We have the technology to turn our civilisation into its’ own carbon-neutral power station without recking global weather patterns or deserts, which is fantastic! But, this also shows that even with renewable energy, we need to be careful how to use them. Mismanaged carbon-neutral energy can be nearly as devastating as fossil fuels.