Space-Based solar power, the idea of building massive structures to orbit the earth and beam energy back for our use is, let’s be honest, a fringe concept: it’s not business as usual, it doesn’t exist.
Elon musk called it crazy, but others believe it offers a real hope of a zero-carbon future.
One of those believers is John Mankins who used to work for NASA. and is one of the world’s leading experts in the topic of space solar power.
So what is space based solar power?
The idea of harvesting sunlight in space and delivering it wirelessly to markets here on earth. So in space you would convert incoming sunlight, usually with photovoltaic cells just like we do here on earth into electricity.
That electricity would be converted into microwave energy, transmitted from antennas and sent in a coherent beam to a targeted location on earth, where the microwaves would be converted back into electricity, and it would be distributed just like energy.
From a earth-based pv array into the electrical grid at the receiver, so can you just talk to me about the scale of this system that you’re describing a typical transmitter in space? That we’re studying would involve a transmission of about 2 000 megawatts of electricity?
That’s enough for about one million homes, the transmitter for that would be a little bit more than a mile in radius about one and a half kilometers and on the ground kilometers away. The receiver would be about six kilometers in diameter. Now a six kilometer radius for the receivers seems pretty large when you compare it to say central London or New York, but some of the largest solar farms in India and the US are already have bigger receivers on the ground.
This rectifying antenna is essentially an array of small dipole radio antennas and it would look a lot like a metal cloth fence and it would essentially be transparent to sunlight about 15 or 20 percent filled with these little antenna elements.
Other than that it would be a transparent mesh, so a mesh a bit like a a large fishing net. Is that what you mean a bit like a large fishing net exactly, but with attached to the net approximately the space. Just like the palm of your hand with these little T-shaped antennas, every four or five inches across this mesh. But are there concerns about the safety of this to human life, to animal life?
One of the principal objectives in all of our studies here in the US has been to look at ways to do wireless power transmission that are both affordable and safe.
The peak intensity of the wireless power transmission at the center of the receiver is about one quarter of full summer sun, and so it’s far less intense than sunlight, because the wavelength is long about 12 centimeters.
It’s not capable of breaking the electronic bonds between the atoms that make up DNA and therefore it cannot be carcinogenic.
Manufacturing solar power for space
How would we go about manufacturing something of this scale? The particular concept that we’re looking at is one that would be extremely modular in character.
Each of them would be composed of a very large number of much smaller modular elements like thinking about building the empire state building out of children’s blocks.
Each block is quite small and quite inexpensive and mass-produced, but the overall model that this child might build might stand. Three or four or five feet tall can be huge.
The idea of wireless power has transfixed scientists and engineers for decades. It goes back to the dawn of the 20th century and Nikola Tesla, who wanted to develop wireless transmission of electricity in New York, but he couldn’t secure the investment, so the project was abandoned.
Could this also be the fate of today’s space, solar power projects, by 1977, nasa was claiming that space-based solar power could replace fossil fuels. It’s reliable, will probably last billions of years, and if you collect its energy from above the earth’s atmosphere in space, it can be done continuously at the goldstone station in California.
A tracking dish is being used to simulate an energy satellite in space. It sends an invisible beam of microwave energy to this rectena, which represents a ground receiving station. The microwave is converted to electricity and powers.
The lights you see here. This is a small scale. Demonstration of how a solar satellite would send its power back to earth by building huge solar satellites in space NASA believes some of the sun’s tremendous energy can be captured to lessen our dependence on more conventional fossil fuels.
But what if the first real-world use of space-based solar power was nothing to do with the zero-carbon revolution, but was really to serve the needs of the military. Boeing’s x-37b controlled by the US defense department is a top-secret, robotic spacecraft that looks like a tiny space shuttle.
In May 2020 orbital test vehicle 6 was launched to low earth orbit aboard an atlas v rocket. It was carrying a space-based solar power experiment designed by the US naval research laboratory.
The equipment transforms solar power into microwave energy, then starts transmitting that energy to earth. It remains in orbit.
The aerospace corporation is a federally funded research and development center that focuses on game-changing technologies in the space sector.
Initially, we’re going to be looking at very discreet applications. Someone who is in a forward deployed military base understands the dire need for energy and, in fact, a lot of coalition deaths result from fuel transportation activities, so paying more for that type of energy makes sense in that situation.
The same for very remote regions of the planet, the same for post-hurricane response, where a lot of the deaths were the result of not having power for nursing facilities and hospitals. So if you look at it, it’s complementary in the scheme of what our energy needs might be in the future. There is utility scale solar power on the grid, and there is the power beaming, agile type of solar power that you can provide for very discreet needs For different customer bases.
It is possible pushing out decades that this could advance to the point of being competitive, but we don’t know that yet Elon Musk’s criticism of space-based solar was that the energy loss during conversion would never make it cost-effective compared to ground-based solar generation.
Elon Musk talks about how there’s really only about two times more sunlight in space than there is on the ground and therefore it doesn’t make any sense because you have to convert it. He is radically wrong. In his numbers that he cites in that interview, it’s an ad hoc thing was off the cuff. This is not a subject that he wants to talk about. He likes to talk about his programs, not somebody else’s program or some other idea.
I know that Elon Musk referred to it as the stupidest idea. Ever. However, he said that in the context of directly competing in the exact same market for the same power source, I would compare that to a two hundred thousand dollar Tesla roadster versus a fourteen thousand dollar chevy spark they each have their consumers that appreciate what they’re producing
The same applies here during our conversations. There was one country whose name came up every single time. There is ongoing activity in China. Well, China is expecting a prototype next year.
We know that the Chinese are working on this everybody we spoke to mentioned China, so we asked a china space expert what the country’s plans are for space-based solar power. So at the moment we see that there is an experimental power plant being constructed in the southwest of China and there have been low altitude tests of transmitting power via microwaves.
It’s hard to see if they are very serious about actually seeing this project, which would be completed by around the middle of the century. One thing they’re looking at is something called the long march 9 and that rocket would be comparable to say NASA’s, sls or the Saturn V, which took the Apollo astronauts to the moon.
So they would have to develop a reusable version of this. If you can’t make an economical launch vehicle which you can reuse, then it’s it’s not going to be possible.
There was a presentation by a chief designer and he’s also involved in the committees. Looking into space-based solar power, his presentation in July of this year indicated plans for a reusable version of this long march 9 and multiple launches.
It’s hard to know whether this is something which is backed at very high levels, or if this is one official who has seniority and is able to speak freely, whether he’s kind of making a pitch. So I think, maybe getting something into low earth orbit in 2025.
Something larger which will be capable of demonstrating, maybe a megawatt of power capacity around 2030 and then moving on by 2050. Having this kind of 10 000 ton space power plant in orbit, we don’t get to see china’s decision-making process and the budgeting, like you, do with the us with its base activities.
But hopefully they have said okay by 2025, we’re looking to have a demonstrator in low earth orbit. That would be a good indication that they’ll move on to more challenging higher orbits and higher levels of power generation. But it’s not just the space superpowers who are considering this technology.
Is solar power in space feasible?
The UK government asked consultancy, Fraser Nash, to assess the viability of space-based solar power and their report was published in September.
It concluded that space-based solar power is technically feasible, economically competitive and well aligned with UK government priorities and the national grid, which operates the UK’s electricity network, doesn’t rule it out either. So, for me, the potential is unlimited.
One of the downfalls that we’ve seen over the years of wind and solar is that the wind doesn’t always blow and the sun doesn’t always shine when we need it to shine.
If we look at the UK’s electricity patterns over a month say in october this year, solar power is only generated during the daytime and it varies a lot with the weather.
Wind generates power day and night, but it’s quite random and unpredictable gas is easily turned on and off, but you can see it’s being used to fill in the gaps when the other energy sources are lower and we emit CO2 every time we use it.
Nuclear is practically a straight line: it’s continuous and reliable and used as a base load for all power generation, but nuclear power stations are hugely expensive. Long-Term projects, which can face local opposition advocates of space solar power, say that it could provide a similar pattern to that of nuclear without requiring or leaving behind radioactive materials.
It would function day and night because a solar station in space would be far enough away to avoid the earth’s shadow. When you have electricity on demand 24 hours a day from space, you don’t need to worry about that at all. So it’s absolutely perfect for a base load.
International grid is a company that has to make profit. It has to supply power. You know to its customers 24 7, but it has to do it profitably. Can you ever see space-based solar power being economical?
What about the cost?
Absolutely so it’s estimated that the cost of space-based solar is going to drop to about three to four pence per kilowatt hour, so this could be half the cost of the electricity that we’re providing today so from a business model perspective.
This is also incredible because you can sell this energy to other countries. You can point it anywhere. So if you don’t need it in the uk, why don’t you sell it to New Zealand, sell it to Australia, sell it to some place else around the world? You need to make money for this thing to be sustainable.
We talk about sustainable and renewable sustainability means being able to make some money, so you can continue to fund these types of initiatives. Can it ever be commercially competitive? Initially, it would be competitive for discrete markets.
Terrestrial utility scale – solar, is very cheap. Now, in fact, in some places it’s actually more competitive than coal. So one way to view space-based solar power would be complementary to terrestrial solar with some other types of technologies advancing.
It is possible to make it more, affordable and more commercial over time. We’re not there. Yet all the core physics of a solar power satellite are in every single communication. Satellite. that’s ever been launched going back to the 1950s, it’s all in the engineering and how you put them together and how you get the efficiencies up and the costs down.
This has traditionally been seen as the domain of science fiction. Certainly there is an unconscious bias, I would say by a lot of people to say, space solar. What the heck are you thinking a little bit of research will really bring it home the unlimited possibilities of this and the benefit that this would bring to our environment.
I think we will see space based solar playing a huge role in our energy ecosystem in the next 20 years, and people will think about all those mad scientists that you know came way before me that were far more futuristic and intelligent about this. They will be proven right that this is actually doable.
Read More: How do solar panels work?
