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Space-Based Solar Power Is No Longer A Pipe Dream, But A Viable Planet-Saving Technology
This solar panel breakthrough is ideal for space-based solar power.
In space, you can feel the full ferocity of the Sun 24/7. With no atmosphere or clouds in the way, the levels of light heat and radiation are insane. This is why solar panels in space, such as those on satellites or the ISS, produce 40 times more power annually than those on Earth. This has led to scientists dreaming of launching vast solar arrays into orbit, and beaming their power back down to Earth as a far more efficient and reliable alternative to terrestrial solar power. But, researchers at the University of Pennsylvania have just created super efficient solar cells that are only a few atoms thick and hyper energy dense, which have the potential to unlock this sci-fi fantasy. But how? And could this be the ideal planet-saving energy source we have been looking for?
Before we dive in, let’s first understand why space-based solar power is so damn good. While terrestrial-based solar power is pretty good, it does have some significant drawbacks. Firstly, the wavelength of light that contains the most power, UV, is filtered out by the atmosphere, meaning that even on a clear day, terrestrial solar panels only output a fraction of what they could. Their power output also massively fluctuates thanks to day and night, and the weather. We can compensate for this by building mega batteries to store surplus energy and ensure there is always enough to meet demand. But these batteries are damn expensive, and not kind to the planet at all! What’s more, solar farms take up vast swathes of land, and can cause habitat loss either directly or indirectly.
But, if we instead strapped these solar panels to a satellite in geostationary orbit, it would get sunlight practically 24/7 (only 14 minutes in the Earth’s shade), the panels would get unfiltered, more powerful sunlight, and there would be no loss of habitat to solar farms. What’s more, with this method, you need far fewer panels for the same output, and as solar power’s carbon emissions mainly come from panel production and battery production, space-based solar power has the potential to have a far smaller carbon footprint per kWh!
However, there are some significant challenges to this technology. Namely, how do we efficiently beam the energy hundreds of miles back to Earth? And how do we get these giant solar arrays into orbit without costs rising to unfathomable levels, or pumping out so many carbon emissions to render the whole endeavour moot? Well, we have made some sizeable progress in these areas. Scientists have created scale-model microwave-based energy transmitters that can in theory beam energy down to Earth, even through cloud cover. SpaceX has also slashed the cost to get to orbit, and with Starship will soon be able to take 100+ tonnes into orbit on a single flight. What’s more, Starship uses liquid methane as its fuel, which can be easily sourced as a carbon-neutral biofuel.
However, despite all of these huge leaps forward, space-based solar power remains out of grasp, as the vast amount of solar panels we would need to put into orbit to make it worth-while is simply too large, making it a logistical nightmare.
But a recent breakthrough in solar cell technology is set to change this. Let me explain.
Professor Jariwala and his team at the University of Pennsylvania have been tinkering with extremely thin solar cells only a few atoms thick that still absorb just as much light as commercial solar panels. These types of panels have been around for a while now, and have been nicknamed 2D TMDC’s due to their unbelievable thinness. However, these cells have been quite inefficient, maxing out at around 10%, which is half that of conventional solar panels, rendering them as more of a novelty technology, rather than a useful one.
But these researchers were able to double the efficiency of these cells! This means they now have a power density of 100 Watts per gramme! For some context, regular solar panels produce 0.13 Watts per gramme, making these panels 769 times more power dense!
This makes these panels ideal for space-based solar power, as you can launch far more solar power per launch. Take the upcoming SpaceX Starship. It can take roughly 100 tonnes into orbit. Let’s assume a space-based solar farm is 75% solar panels and 25% structure and energy transition systems by weight. If you used regular solar panels, this array would have a power rating of 9.75 Mega Watts, or about 100th the output of a nuclear reactor. If instead we use these new super-thin hyper energy dense panels, we can pack in a massive 7.5 Giga Watts of power. That’s the same power as about 8 nuclear reactors!
In other words, these solar panels could make space-based solar power commercially viable, as it can dramatically reduce its cost.
Now, while this is still a huge leap forward, there are still numerous hurdles to overcome before this technology can come to fruition. After all, no one has yet built a fully functioning space solar farm. But there are several projects around the world aiming to do just that.
Take JAXA, the Japanese space agency, they want to build the world’s first commercial-scale solar farm by 2025! Their space-based solar project has been going on for well over a decade. Their project will attempt to deploy a series of small satellites in orbit, which will then try to beam the solar energy the arrays collect to ground-based receiving stations hundreds of miles away.
Europe’s ESA is also aiming to unlock space-based solar power. In 2022, they conducted a cost-benefit analysis of space-based solar and found that it could; provide competitively priced energy to European homes and businesses by 2040, would be an ideal complementary energy source to terrestrial solar, wind power and could provide energy security, and it can provide substantial environmental, economic, and strategic benefits to Europe. But research and development needed to start straight away for this to be the case. As such, they started project Solaris, whose aim is to develop new, more robust, longer-lived, and high-power solar panels than we currently have, invent ways to build these massive orbiting solar arrays over several launches and develop their own high-efficiency energy transmission technology. (read more here).
Even China is getting in on the action. They are planning to build and launch a 10 kW prototype space-based solar system by 2028. (read more here).
All of these projects will enable us to iron out any kinks with space-based solar power and develop the technology, systems, protocols and personnel needed to launch this technology from concept to viable energy solution. When that time comes, it’s technology like these ultra energy-dense solar panels that will enable us to adopt space-based solar power at an eye-watering pace and unlock an era of superabundant, super clean energy!
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