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Oct 5
Have We Got Solar Power All Wrong?
We are using solar power arse-about-face; there is a much better way to use this planet-saving technology.
We are in a desperate race to change our ways and save this beautiful planet from our self-made apocalypse. The only issue being, there's no silver bullet that can single-handedly solve climate change. Take solar power, for example. It is one of the cheapest and lowest carbon forms of energy we have, but it also causes rampant habitat loss by using up vital land areas. In its current form, we can't power ourselves using this revolutionary energy source because it could cause an entirely different environmental problem. But what if I told you that a simple change could make solar power more efficient, decrease its carbon footprint, have a negligible impact on ecosystems, and even directly reduce global warming? Sounds too good to be true? Well, welcome to the fantastic world of floating solar power.
Before we go diving into floating solar, let's first explain the shortcomings of current solar power systems.
When I say solar power causes habitat loss, I don't always mean directly. Sure, you might demolish a bit of forest to build a solar farm, which would cause habitat loss, but for the most part, solar farms are built on farmland, which reduces a country's farmable land area. This means that either that country's farmland needs to expand or food imports need to increase. Either way, the solar farm causes humans to use far more land, negatively impacting wildlife and the overall environment.
Plus, solar panels have a low albedo. Albedo is the measure of how much light a surface reflects, and because solar panels are only around 20% efficient, they heat up dramatically in the sunshine. This, in turn, means they emit a lot of infrared radiation, which heats up the carbon dioxide in the atmosphere, trapping the heat in the Earth's atmosphere and causing global warming.
In contrast, forests, grasslands, and farmlands have a higher albedo, meaning they don't heat up and instead reflect most of the light in the visible spectrum rather than infrared. Carbon dioxide is transparent to the visible spectrum, so this reflected light doesn't warm it up. In other words, replacing vast swathes of plant-dense land with solar panels can slightly increase global warming.
Now, we can solve this by using rooftop solar instead. Because roofs have a similar albedo to solar panels, this keeps the average albedo of the Earth the same and means solar doesn't cause habitat loss. But because of the complex energy infrastructure and inaccessible nature of rooftop solar, it costs up to 44% more than a regular solar farm!
Thankfully, by using rafts to float solar panels on bodies of fresh water, we can solve all of these issues, keep the costs low, make them more efficient, and have a lower carbon footprint. Let me explain.
Firstly, using this method prevents habitat loss due to the reduced amount of impact on farmland and wild land. Providing the panels don't cover the entirety of the lake, reservoir, canal, or river, the marine ecosystem should also be mostly unaffected. This is because freshwater ecosystems, particularly those in the deeper lakes, have algae at the base of their food web. Unlike plants, algae can move around, meaning that total shade isn't a death sentence as long as they can travel to an area with light. In fact, lowering the amount of algae in freshwater can be very beneficial for the aquatic ecosystem as it prevents harmful algal blooms from killing everything in the water every few years or so.
The water also keeps the solar panels much cooler than they would be on land, and like every other type of electronic, this increases their efficiency by up to 15%. That is a significant leap! But cooler panels also last longer, as they suffer less thermal damage, so floating solar has a longer lifespan too. Not only does this mean a floating solar farm can be far more compact than its land-based kin, but it also means it has a smaller carbon footprint.
You see, the vast majority of the carbon footprint of solar energy comes from manufacturing solar panels. It takes an enormous amount of energy to refine the raw materials and assemble each panel, and then, after that, the emissions are practically zero. So, by increasing the efficiency and extending the life of a solar panel, floating solar can further reduce solar's already tiny carbon footprint.
Water also has a lower albedo than solar panels, so floating solar doesn't add to global warming like terrestrial solar farms — in fact, it actually reduces it. Moreover, still bodies of water act as thermal batteries, storing heat in the depths over the summer and warming the surrounding environment during the winter. This effect is significantly reduced by floating solar panels, as they stop the water from heating up in the warmer months, which helps keep the planet a little cooler.
There is also the fact that floating solar can stop vital drinking reservoirs from drying up by providing shade and reducing surface wind speeds, which stops excessive evaporation. This is the same as the "shade balls" made famous by Veritasium.
We can make floating solar even better when we combine them with hydroelectric reservoirs (the bodies of water made by hydroelectric dams). These locations already have the infrastructure needed to transmit energy to high-demand areas, making the transmission infrastructure very efficient, and as a bonus, the reservoirs are gigantic.
A recent study showed that covering 10% of the world's hydroelectric reservoirs with floating solar would produce up to 10,616 TWh of power per year, which is an astonishing amount of energy. For some context, the world consumes 23,900 TWh of energy per year. This means that covering 22.5% of the world's hydroelectric dams with floating solar panels could power the entire globe!
What's more, thanks to recent innovations in hyper-efficient long-distance energy transmission (such as XLink; read more here), it is actually practical to power the world in this way.
So, by simply changing the location of solar panels, we can make them less ecologically damaging, more efficient, longer-lasting, less polluting, and give us the space we need to build the gigantic solar farms to power our civilisation. Fantastic! So what's the catch?
Well, floating solar costs up to 15% more to build than an equivalent terrestrial solar farm. But this isn't a huge issue.
Firstly, in the right situation, the increased efficiency of the floating solar panels can offset this expense and make the cost per kWh the same as terrestrial-based solar farms. But also, solar farms are the cheapest form of energy ever, with a price as low as $30 per kWh! For some context, nuclear power costs at the very least $131 per kWh, and rooftop solar hovers at just over $44 per kWh. So a 15% increase (about $34.50 per kWh) is still an absolute bargain! Particularly as floating solar seems to be one of the most eco-friendly energy sources we have.
So yes, we have got solar power all wrong. We shouldn't be strapping it to roofs or filling up valuable farmland with panels. Instead, we should use rafts to float them out onto lakes, reservoirs, canals, and rivers. Sure, this technology can't single-handedly save the world from the ravages of climate change. But it can help humanity take a significant step forward in becoming far more ecologically harmonious. The only question is, will we actually use this incredible technology?
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