Could solar panel arrays boldly go where none have before and help fight the climate crisis in the process?

Believe it or not but various experts and organisations believe just that. 

While the only solar system in space right now is the one that orbits the sun, in the coming decades, it's entirely possible that this new frontier of renewable energy may truly take off. 

But how viable is it? And what are the pros and cons? 

What is Space-based Solar?

The idea behind space-based solar power or SBSP is that you'd have a PV solar panel array located high up in Earth orbit that is capable of transmitting the sun's energy back to Earth wirelessly. 

More specifically, such a system would involve inflatable mirrors/reflectors capable of directing solar radiation onto panels before converting this energy into microwave energy. 

This energy would be sent wirelessly to the Earth in the form of an invisible microwave energy beam (don't worry research is taking place to ensure the safety of this technology, which we'll discuss more of later). 

The energy would then reach a microwave antenna, also known as a rectenna, on Earth where it would be converted into electricity.

How Viable is Space-based Solar?

While solar panel arrays in space may sound like the stuff of science fiction, it is not as futuristic as it sounds. 

In fact, the concept behind space-based solar (i.e., wirelessly transmitting energy in the form of microwaves before converting it into electricity) has been a proven idea for many decades.

One example of this concept being put into practice was seen with a 1978 study by NASA in relation to solar power satellites. 

In this case, they performed research on Earth whereby a 1km diameter antenna sent a microwave beam (at 2.45 GHz) to a 10km rectenna before being converted into electricity.

So, the concept behind space-based solar is sound, at least on a small scale but could it work on a larger scale with space-based solar systems? That has yet to be proven but an interest in testing out and even commercializing such technology is on the rise.

Of course, sufficient efforts and further investment (we look at current investments below) will be required to make space-based solar a reality, however, based on research up to this point, it is feasible.

One aspect of space-based solar that could make it more than worthwhile is the efficiency. Some estimates suggest that space-based solar could generate over forty times as much solar energy as the same array located on Earth. 

However, other claims suggest that it might be closer to x10 what is possible on Earth. Either way, these would be impressive figures if made a reality.

The Race to Save The Planet

In 2015, global mean temperature warming reached one degree Celsius over preindustrial times for the first time. This was the result of a gradual (but accelerating) process of global temperature warming due to human activities.

Per the Paris Agreement, the world's nations are aiming to limit the average global temperature (since pre industrial levels) firmly below 2°C and as close to 1.5°C as possible.

With our world facing countless disastrous consequences from a warming planet (which in all likelihood will involve the Earth nearing or surpassing two-degree warming), there is growing urgency to reduce global emissions.

Earth-based renewable technology is one weapon in our humanity-saving arsenal; however, it will still take many years before such technology can meet most of our energy needs. 

What's more, while nuclear power is another alternative to fossil fuels, it remains a controversial option and its use on a global scale is stagnant without much growth towards increased use of fission power. 

There is, of course, research into nuclear fusion (which promises a bountiful energy revolution), but its commercial viability is also decades away if not more. Despite recent breakthroughs, the joke over nuclear fusion always being twenty years away remains a popular trope online. 

Perhaps that will change eventually as it becomes more commercially viable but only time will tell how fast nuclear fusion will develop from here.

Ultimately, space-based solar could prove very advantageous if the right funding and desire is there to make it a reality. 

Obviously, it too would take decades to master but if there were fully operable commercial solar systems in space in say 40 years' time, this could accelerate global efforts to reduce and eventually eliminate fossil fuels.

As great as a net zero world would be (which may be feasible around the middle of the century), we really need a zero-carbon world or/and major advances in carbon reduction technology to human-made global warming entirely. 

Therefore, space-based solar could help humanity make a major push toward this ultimate environmental goal toward the end of the century. But what is the state of space-based solar in 2023?

Current Research and Plans

The United States, China and Japan are among the primary nations investing in space-based solar research. However, the UK government has also expressed interest.

Starting across the Atlantic, there exists a $100 million partnership between the U.S. Air Force Research Laboratory and multinational aerospace and defence technology company Northrop Grumman to develop and further SBSP.

Moreover, there is also a $17.5 million initiative with the goal of developing technology so that space-based solar can be made more affordable. 

Beyond that, the development of reusable launch systems (something that private companies like SpaceX are working on) would help make the launch of space solar arrays more economically viable.

China has ambitious plans of its own with the emerging space superpower aiming to first launch a space-based solar array to test the concept in practice in 2028. 

Their current plans involve performing such a test in low Earth orbit in 2028 before establishing space-based solar in geosynchronous orbit in 2030.

Of course, many government space ambitions tend to be delayed (whether from China, the US or elsewhere), so whether or not these targets will be met is yet to be seen but the ambition clearly exists.

The Chinese government is also targeting to generate a megawatt of solar energy via a space-based setup in the coming decades before creating a commercially viable space-based solar plant by mid-century.

Another country which has delved into this area is Japan. For instance, researchers in Japan have also successfully transmitted electric power wirelessly via microwaves. Beyond that, space-based solar is part of the future vision of Japan's space exploration for the Japanese Aerospace Exploration Agency (JAXA).

Notably, even the UK government has expressed interest in space-based solar. For example, in 2022, the government ran the Space Based Solar Power Innovation Competition which serves the purpose of providing grant support to projects that relate to SBSP.

In addition, a study from the Department for Business, Energy & Industrial Strategy found that space solar power is not only technically feasible but affordable and could support the UK both economically and in terms of its push toward Net Zero by 2050.

Does this mean that the UK government are going to back UK space solar arrays in the future? While it does seem unlikely given that countries like China and the US have far larger budgets to work with, it's not entirely impossible.

Would Space Solar Power Be Safe?

One important focus of SBSP research is to determine its level of safety. Of course, the public will need confidence that space-based solar is not a health hazard to get behind such technology.

According to ex-NASA physicist John Mankins the peak intensity of the wireless energy transmission at the centre of a rectenna of a proposed SBSP would be less than that of regular sunlight. 

Moreover, with the wavelength being long (about 12cm), it would lack the ability to break apart the electron bonds of atoms in DNA. Therefore, it done properly such systems would not pose a cancer risk.

Ultimately though, more research will be required to reassure the public. Naturally, more research into any potential concerns should take place as this technology evolves and particularly if it starts to gain ground.

After all, space-based solar has not yet been tested in practice, so there is always a chance that new issues or concerns may arise (whether health-related or otherwise) once the practical testing phase gets underway.

Pros and Cons of Space-based Solar Power

As you'll already have a sense of, there are a range of advantages and disadvantages to using solar panels in space to power homes and businesses on Earth. We'll now look at these in more detail.

Pros

• SBSP is feasible - While space-based solar may seem a little absurd at first (at least at this stage in history), as highlighted by Heatable, data suggests that solar panels in space could not only work but prove commercially viable.

• Much more energy - As discussed, space-based solar arrays would generate far more energy than those located on Earth, potentially somewhere between x10 and x40 as much, if not even more! Combine this fact with the emergence of reusable launch vehicles and their potential to become more common in the future and SBSP is shining bright as a prospective technology.

• Wireless beamed energy - Notably, this technology could be beamed practically to anywhere on Earth. This would make it especially useful for remote locations without access to a national energy grid (e.g., bases in Antarctica) and to transmit energy to areas that are suddenly cut-off due to natural disasters. Being able to beam energy wirelessly from space could ultimately save lives as for instance it could help ensure that life support technology remains active as a last resort backup.

• Can offer 24/7 zero-carbon electricity - Not only would space-based solar be a zero-carbon solution to our energy needs but these systems could generate energy 24/7. This is because proposed systems would be located high enough up in Earth orbit that they would never be subject to the Earth's shadow. This would mean constant access to sunlight and thus constant energy generation.

• May even power airplanes mid-flight - Airbus has even envisioned space-based solar benign used to power aircraft and help push the aviation industry toward a low- or zero-carbon future.

Cons

• Highly ambitious - While space-based solar could prove commercially viable, getting such projects off the ground (and above the atmosphere to Earth orbit) will be no easy feat. This is particularly with regards to ensuring that the funding is there to back and maintain large solar systems orbiting the Earth. More than likely this would require consistent government backing, although private space companies are already showing their potential when it comes to space launch.

• Space debris and geopolitical hazards - One major issue that SBSP would face that Earth-based solar arrays would not is space junk. If even a tiny piece of debris struck a solar system, it could cause serious damage or even destroy it due to the immense speeds involved in objects orbiting the Earth. Aside from a space debris accident, there's also the risk of a solar system being intentionally destroyed. Already, in 2021, Russia performed a test in which they blew up one of their own satellites. As technology and geopolitics are involved, the risk of space conflict may be ever present. Furthermore, by 2050 or 2060, non-state actors may even be capable of interplanetary sabotage. The future brings with it plenty of hope but also new potential threats.

• Micrometeorites - Similarly to space debris, micrometeorites could strike space-based solar panels and either damage or entirely destroy them. Ultimately, whether the danger be man-made or from the heavens, we will likely need to see innovations in space monitoring (perhaps something resembling air traffic control but for Earth orbit) to ensure that future SBSP projects are kept as safe as possible.

• Adding to space debris - When a solar array reaches the end of its life, there is a serious risk that it could break apart and add to the existing space debris. Either way, a redundant solar system will only add to the amount of unnecessary material in space, which could prove a hazard to manned and unmanned spacecraft. 

• Light pollution - Some concerns have been raised that due to the light reflecting element of hypothetical space-based solar arrays, they may end up looking like little stars in the sky. While this may not be a huge deal for most people, it could prove an issue for astronomy. Debate on the potential light pollution of SBSP is ongoing and will certainly continue if space-based solar gathers more momentum.

Are Solar Panels in Space the Future?

It's impossible to say at this stage whether space-based solar will be our future. However, there is real potential and so far, it looks like solar panels in space would be commercially viable if there was sufficient investment to get the necessary projects off the ground.

Of course, even if SBSP could be part of humanity's future, which doesn't guarantee that they'll be ready for commercial use in time to help alleviate the climate crisis. Obviously if humanity wants to survive into the 22nd century and beyond, we'll need to find large-scale solutions in the near future while taking the necessary steps toward a green future that are currently within our grasp.

The next 10-15 years may make or break the prospect of there being SBSP en masse within our lifetimes (if ever). Right now, there are emerging signs of government and private interest in space-based solar and if momentum gathers, then anything is possible.