Green Energy

To manage future electricity demand in line with the EU’s Energy Roadmap 2050, power grids need to rely on both supply and demand flexibility and be structured as a system of systems. The ongoing energy crisis, which started in summer 2021 due to low natural gas supply and which further deteriorated with the Russian invasion of Ukraine, has highlighted the urgent need for a more independent European energy policy. The EU’s Energy Roadmap 2050, via which the EU wants to become climate-neutral by 2050, is a great opportunity to reduce—or halt—the bloc’s energy dependence from neighboring countries, but it also presents challenges. In the next 10 to 30 years, and because of the strategy itself, European electricity demand is expected to rise, thus requiring supply, particularly from renewable sources, also to increase. The problem with renewable sources, especially solar and wind power, is that they create fluctuating energy patterns which sometimes cannot match demand, and this might result in grid overloads. For example, today in Europe there are approximately 1.5 million electric vehicles, while the EU target for 2030 is 30 million. If all 30 million electric vehicles were to charge at the same time with the current grids, the system would not cope. In order to match electricity demand, the system requires either flexibility on the consumption side or flexibility on the generation side or, ideally, on both sides. But what does this mean? Electricity requires one thing above all: it has to be consumed when it is generated. We cannot predict when a wind mill will produce electricity, because it depends on the wind. So how can we balance this situation? This is where you need to introduce other elements such as storage capacity on the supply side and demand side management on the consumption side. This means, for example, that electric car drivers cannot plug in their car whenever they like; they need to choose a specific time when the generation is available. ENTSO-E, the European Network of Transmission System Operators for Electricity, recently published a paper that presents a comprehensive vision of what is necessary to achieve a power system fit for a carbon-neutral Europe. “This future power system in Europe will be a System of Systems, which will need strong cooperation between transmission and distribution, and amongst different energy systems. All operators will be key enablers and facilitators to make this future energy system work,” the network said in the paper. It added, “At the same time [it will be] more European and more local, with transmission system operators providing a critical interface between both dimensions.” ENTSO-E highlighted that such a power system is within reach, although four elements must change to make it possible: the development of large-scale system flexibilities, timed with the future system needs and the gradual phasing-out of fossil fuel generation; an operation of the system that will rise up to the challenge of this much more complex System of Systems through innovation and cooperation; a facilitating regulatory framework and a market design as a key enabler. From an economic point of view, the flexibility element represents the biggest cost at the moment, although Smart Energy Europe (SmartEn), a European business association integrating the consumer-driven solutions of the clean energy transition, recently published a study on how demand-side flexibility could lead to big savings for both consumers and electricity distributors. According to SmartEn, a scenario that allows the full activation of flexibility from buildings, electric vehicles, and industry in 2030 could result, every year, in 37.5 million tons of greenhouse gas emissions saved, €11.1—€29.1 billion saved in distribution grid investments, €71 billion saved by consumers directly, 15.5 TWh (61%) avoided renewable curtailment and €2.7 billion saved in avoided peak generation capacity. “The more variable the renewable energy system is, the more you have risks of congestion in the system, so we need to make sure that flexible consumers are actually receiving the signals to consume in this time-dependent way based on renewable generation,” Michael Villa, Executive Director at SmartEn commented. He added, “If there is too much renewable generation, renewable providers need to stop production in order to avoid congestion in the system, which is costly. But if you are indeed giving consumers signals that they need to consume or store even more of this abundance of renewable generation, then you will reduce these renewable curtailment costs.” The gradual improvement in the grid, the increase in renewable energy and the flexibility required within the grid are also being implemented in smart cities such as Antalya, Dresden and Valencia, which are part of the MAtchUP European research project. MAtchUP aims at transforming cities through innovative solutions and technologies at the service of local communities. It envisages specific measures to improve the share of renewable energy, increase sustainable mobility and invest in technology. “Grids, as of now, are not ready; we have to change the infrastructure and move to a completely different one. A major challenge is that it’s a new type of load for the electricity grid, which means we would need more energy to cover the electricity demand from electric vehicles, so we need more capacities to begin with,” Ömer Akyürek, head of the energy team within MAtchUP said. And it’s also a matter of how fast consumers want to charge their electric cars. “No one is willing to wait half a day for the charging time, consumers want it fast and immediate. This requires high powered charging stations which can transfer a lot of energy very quickly. But, this creates a peak in demand on the grid and that’s a problem. How can we manage those peak loads, can we install storage capacity, can we link this storage capacity and charging demand with renewable energy?” Akyürek concluded by adding that these are measures to help smart cities to tackle the peaks issue and manage the stability of the grid and electricity demand.

Japan’s first large-scale offshore wind farm started operation on December 22 – a major milestone in the country’s transition to renewables.

Japan already operates several demonstration offshore wind turbines, but this is its first commercial offshore wind farm.

The 140 megawatt (MW) project consists of two offshore wind farms – Noshiro and Akita. Noshiro Port offshore wind farm is around 300 miles northwest of Tokyo in the Sea of Japan, in Akita Prefecture. It’s the Noshiro Port part of the project that just came online. The Akita Port offshore wind farm’s “commercial operation based on FIT is expected in due course.”

Noshiro and Akita together have 33 fixed-bottom Vestas wind turbines that were installed by UK offshore installation firm Seajacks International.

Noshiro features 20 4.2 MW wind turbines, and Akita has 13 4.2 MW wind turbines.

The offshore wind project will provide electricity to Tohoku Electric Power, which has a 20-year power purchase agreement for the wind farm’s entire output. It will power around 150,000 households.

Tohoku Electric Power services 7.6 million individual and corporate customers in six prefectures in Tohoku region, plus the Niigata Prefecture, in Honshu.

The Akita Offshore Wind Corporation owns the project. Tokyo-based investment firm Marubeni is the largest investor in Noshiro and Akita, and many other Japanese companies are invested, including utilities and banks.

Japan aims to install up to 10 GW of offshore wind capacity by 2030, and up to 45 GW by 2040.

Currently, 25% of Japan’s electricity comes from renewables. It has a plan to bump that percentage up to 38% by 2030.

At the end of May, for the first time and joining the other six member states of G7, Japan pledged to end public financing for fossil fuel projects abroad by the end of 2022.

Demand for solar panels has shot up to unprecedented levels in Spain as Europe’s energy crisis shows no sign of letting up, in a welcome boost for a sector with huge potential.

“Here we have sun almost all year round,” said Paloma Utrera showing off the black panels installed on her roof in Pozuelo de Alarcon, a well-heeled suburb of western Madrid.

“We need to make the most of it.”

Like many Spaniards in recent months, Utrera has started producing her own electricity after installing 13 photovoltaic panels on her roof with a total output of 4.5 kilowatts.

“It’s not cheap” but with the help of EU and government subsidies, “the savings we’ll make on the electricity bill, the investment isn’t that bad,” she said.

The 50-year-old airline industry employee said she’s halved her electricity bills since having the solar panels installed in September.

“It’s a really worthwhile investment,” said Utrera.

According to Engel Solar, which carried out the installation, rooftop solar panels can generate between 50 and 80 percent of the average household’s electricity needs.

And given the current prices of electricity, that makes for an “interesting” proposal, said Engel Solar commercial director Joaquin Gasca.

Set up in Barcelona in 2005, the company with 200 employees has seen its turnover soar fivefold over the past two years and expects to see a further jump in 2023.

“The phone just never stops ringing, it’s crazy,” said Gasca.

A rooftop investment

And it’s not just individuals.

Businesses and public entities are also getting on board, driven not only by the energy crisis linked to the war in Ukraine but also encouraged by the public funding available through the EU’s vast COVID recovery plan.

All of this has given an unprecedented boost to rooftop solar in the Iberian peninsula.

“Until about a year ago, if you looked at the rooves in your town or city, you would hardly see any solar panels for self-generation… but that’s totally different now,” said Francisco Valverde, a renewable energy specialist at Menta Energia consultancy.

Jose Donoso, head of Spanish solar power lobby UNEF which groups some 780 businesses, agreed.

A new approach to manufacturing perovskite solar cells has addressed previous problems and yielded devices with high efficiency and excellent stability, researchers at the National Renewable Energy Laboratory (NREL) report in the new issue of the journal Science. Developing highly stable and efficient perovskites based on a rich mixture of bromine and iodine is considered critical for the creation of tandem solar cells. The two elements, however, tend to separate when exposed to light and heat and thus limit the voltage and stability of a solar cell. “This new growth approach can significantly suppress the phase segregation,” said Kai Zhu, a senior scientist at NREL, principal investigator on the project, and lead author of the new paper “Compositional texture engineering for highly stable wide-bandgap perovskite solar cells.” The new approach addressed that problem and produced a wide-bandgap solar cell with an efficiency of greater than 20% and 1.33-volt photovoltage and little change in the efficiency over 1,100 hours of continuous operation at a high temperature. With this new approach, an all-perovskite tandem cell obtained an efficiency of 27.1% with a high photovoltage of 2.2 volts and good operational stability. In the tandem cell, the narrow-bandgap layer is deposited on top of the wide-bandgap layer. The difference in bandgaps allows for more of the solar spectrum to be captured and converted into electricity. Perovskite refers to a crystalline structure formed by the deposition of chemicals onto a substrate. A high concentration of bromine causes more rapid crystallization of the perovskite film and often leads to defects that reduce the performance of a solar cell. Various strategies have been tried to mitigate those issues, but the stability of wide-bandgap perovskite solar cells is still considered inadequate. The newly developed approach builds upon work Zhu and his colleagues published earlier this year that flipped the typical perovskite cell. Using this inverted architectural structure allowed the researchers to increase both efficiency and stability and to easily integrate tandem solar cells. The NREL-led group used that same architecture and moved further away from the conventional method of making a perovskite. The traditional method uses an antisolvent applied to the crystalizing chemicals to create a uniform perovskite film. The new approach relied on what is known as gas quenching, in which a flow of nitrogen was blown onto the chemicals. The result addressed the problem of the bromine and iodine separating, resulting in a perovskite film with improved structural and optoelectronic properties. The antisolvent approach allows the crystals to grow rapidly and uniformly within the perovskite film, crowding each other and leading to defects where the grain boundaries meet. The gas-quenching process, when applied to high-bromine-content perovskite chemicals, forces the crystals to grow together, tightly packed from top to bottom, so they become like a single grain and significantly reduces the number of defects. The top-down growth method forms a gradient structure, with more bromine near the top and less in the bulk of the cell. The gas-quench method was also statistically more reproducible than the antisolvent approach. The researchers achieved an efficiency that exceeded 20% for the wide-bandgap layer and operational stability with less than 5% degradation over 1,100 hours. Coupled with the bottom cell, the device reached the 27.1% efficiency mark. The researchers also tried argon and air as the drying gas with similar results, indicating that the gas-quench method is a general way for improving the performance of wide-bandgap perovskite solar cells. The new growth approach demonstrated the potential of high-performance all-perovskite tandem devices and advanced the development of other perovskite-based tandem architectures such as those that incorporate silicon.

Beaming solar power from space used to be considered science fiction. But in recent years, space agencies from all over the world have launched studies looking at the feasibility of constructing orbiting power plants for real.

Such projects would be challenging to pull off, the stakeholders agree, but as the world’s attempts to curb climate change continue to fail, such moonshot endeavors may become necessary.

According to the United Nations’ Panel on Climate Change(opens in new tab), the world is currently on track to warm by 4.5 degrees Fahrenheit (2.5 degrees Celsius) by the end of the century. That is 1.8 degrees F (1 degree C) above the threshold considered safe by the international climate science community to avoid disastrous climate change consequences.

In fact, to limit the warming to anywhere near that threshold, the world’s economies would have to cut down their greenhouse gas emissions by 45% by 2030. That would mean phasing out a lot of fossil-fuel-guzzling technology in a very short period of time.

For example, the United Kingdom would need at least 30 to 40 gigawatts of new on-demand sustainable power generation to get rid of all fossil fuel power generation (according to a 2019 statement(opens in new tab)). That’s the equivalent of building over 30 new nuclear power plant blocks.

Solar power plants in space, exposed to constant sunshine with no clouds or air limiting the efficiency of their photovoltaic arrays, could have a place in this future emissions-free infrastructure. But these structures, beaming energy to Earth in the form of microwaves, would be quite difficult to build and maintain.

Here are the main pros and cons of this technology.

The pros

The technology is less science fiction than you might think

Ian Cash is a British engineer, whose CASSIOPeiA Solar Power Satellite concept has been adopted by a U.K. government-backed space energy initiative as a starting point for a potential future space-based solar power plant demonstrator. A staunch advocate of the technology, Cash thinks that developing and building a solar farm in space presents fewer challenges than cracking nuclear fusion.

When it comes to space-based solar power, “there is no science to solve,” Cash told Space.com. “We have it all worked out pretty much since the 1970s, when NASA with the U.S. Department of Energy conducted a very large-scale study. We’ve proven the physics behind this ever since we first launched a communication satellite into geostationary orbit. You’ve got solar wings, which face the sun. And you have the body of the satellite, either with a parabolic dish or a phased array antenna, which faces the Earth. All the principles are the same; you’re converting solar energy to electricity, converting it to microwaves and beaming it to Earth. The only thing that’s different is the scale of the apertures.”

Andrew Wilson, a researcher at the Advanced Space Concepts Lab at the University of Strathclyde in Scotland, who led a study looking into the feasibility of space-based solar power, agrees: “I don’t think there’s technology that needs to be developed as opposed to just advancing through the technology readiness levels,” Wilson told Space.com. “There’s nothing really that needs to be invented.”

However, as detailed later in this piece, the required “technology advancing” is rather considerable.

It would provide 13 times more energy than an identical ground-based plant

Building solar power plants in space certainly isn’t an easy task, but it seems to have advantages — at least for some countries. The technology’s proponents claim that a solar-power plant in Earth’s orbit would produce 13 times more power than an equivalent installation located in the notoriously cloudy U.K.

Space-based solar power plants would easily produce gigawatts of power, matching the electricity output of nuclear power plants. In contrast, the U.K.’s largest solar power plant, Shotwick Solar Park(opens in new tab) in northern Wales, produces a meager 72.2 megawatts during peak insolation times. Only the world’s largest solar plants, sprawling installations in some of the sunniest countries, reach the gigawatt mark. For example, the Bhadla solar farm in India generates up to 2.7 gigawatts and covers 52 square miles (160 square kilometers) of land, which is more than double the size of Manhattan, according to the Ecoexperts.

Building a solar power plant in space would come with an enormous price tag. Once built, however, the plant would pay for itself much faster than any Earth-based renewable power generating technology, according to Wilson.

It provides perfectly clean electricity 24/7

Space-based solar power doesn’t suffer from the main drawback plaguing most main renewable energy generation technologies. In space, the sun always shines. No clouds ever block the sun’s rays from reaching photovoltaic arrays. And if you choose the orbit wisely, you can even avoid the night. A solar power plant in space, unlike its equivalent on Earth, or an off-shore wind farm, would provide a constant amount of power 24/7 year-round. This power would feed Earth-based power grids at a steady rate without having operators worry about pesky blackouts or sudden overloads.

Space-based solar power proponents, however, don’t expect the heavenly electricity to push out more humble ground-based renewables. They think space-based solar power should replace power plants that are currently being used to cover energy needs when the sun doesn’t shine and the wind doesn’t blow. In the U.K., this so-called dispatchable power comes mostly from oil and gas-fired power plants, the type of carbon-producing facilities that are adding to the world’s growing climate-change problem..

“The thing with space based solar power is that very high levels of power can be delivered, similar to nuclear power plants,” Wilson said. “Most other renewable energy options can’t provide such quantities at once. Without space-based solar power, we would probably be looking to build many more nuclear power stations, for sure.”

Of course, renewable power could be fed into giant batteries in times of surplus generation to be used at times of need. But energy storage technology of this scale is only slightly more solved then nuclear fusion.

It could be beamed anywhere without wires and power lines

Space-based solar power doesn’t suffer from the main drawback plaguing most main renewable energy generation technologies. In space, the sun always shines. No clouds ever block the sun’s rays from reaching photovoltaic arrays. And if you choose the orbit wisely, you can even avoid the night. A solar power plant in space, unlike its equivalent on Earth, or an off-shore wind farm, would provide a constant amount of power 24/7 year-round. This power would feed Earth-based power grids at a steady rate without having operators worry about pesky blackouts or sudden overloads.

Space-based solar power proponents, however, don’t expect the heavenly electricity to push out more humble ground-based renewables. They think space-based solar power should replace power plants that are currently being used to cover energy needs when the sun doesn’t shine and the wind doesn’t blow. In the U.K., this so-called dispatchable power comes mostly from oil and gas-fired power plants, the type of carbon-producing facilities that are adding to the world’s growing climate-change problem..

“The thing with space based solar power is that very high levels of power can be delivered, similar to nuclear power plants,” Wilson said. “Most other renewable energy options can’t provide such quantities at once. Without space-based solar power, we would probably be looking to build many more nuclear power stations, for sure.”

Of course, renewable power could be fed into giant batteries in times of surplus generation to be used at times of need. But energy storage technology of this scale is only slightly more solved then nuclear fusion.

It is theoretically safe from Earth-based conflict

The apparent sabotage of the Nord Stream gas pipelines in the Baltic Sea that shocked the world in September 2022 showed that, in the politically unstable world that we live in, relying on energy from abroad is rather unsafe.

Space-based solar power, proponents say, is more secure from international conflict than gas supplies from Russia — and more secure than traditional solar plants here on Earth as well.

“Some people say that if you strategically place solar panels in certain unpopulated regions in, for example, the Sahara desert, you could power all humanity’s energy needs,” said Wilson. “But the same thing that we have seen happen with Russia could then happen to our energy security if a war erupted in the Sahara region.”

Some opponents argue that a space-based solar power plant could be easily attacked by anti-satellite missiles. Cash, however, disagrees. Shooting down a platform in geostationary orbit, he says, is outside of the current capabilities of most states. On top of that, while disrupting undersea pipelines in a stealth way using submarines allows for plausible deniability, an adversary launching a missile to destroy a space-based solar plant of a rival would be easily identified.

“There certainly is a risk, but it’s no greater than hostile players wanting to attack nuclear power stations, gas pipelines or high voltage power line cables running between continents,” Cash said. “Many of these things can be attacked covertly, and the attacking nation can easily deny responsibility. But in space, any attack involves a launch that will surely be detected.”

Wilson added that, as any space-based solar power plant project will most likely be an international endeavor, the international nature provides an extra layer of protection against political upheavals.

The infrastructure on the ground will be allegedly less obtrusive than that of other renewables

Photovoltaic plants on the ground devour huge areas of land to harvest any reasonable amount of power. Wind farms in the landscape, too, are unmissable. The rectifying antennas (or rectennas) needed to receive microwave beams carrying solar power generated in space would too require a huge footprint. These rectennas will, however be far less obtrusive, claimed Cash, and allow for other uses of the land or sea on which they will be built.

“The rectennas will be a thin mesh construction; they’ll let sunlight through and will be almost invisible when viewed from a distance,” Cash said. “We envisage a future where we could have a rectenna raised up a few meters above ground via poles, and repurpose the land underneath for, say, robotic farming or even human farming, as the land will be underneath a microwave shield, so there will be no exposure to microwave radiation.”

It could power flying airplanes

In Airbus’ idea of the future, solar power produced in space could contribute to cleaning up the hard-to-deal-with carbon footprint of aviation. Not that it would wean aircraft off fossil fuels entirely, but it could make a little dent in the amount of greenhouse gas the world’s aircraft discharge into Earth’s atmosphere.

“In the future, as we move toward hydrogen and battery-powered aircraft, we could use space-based solar power to extend the range of aircraft,” Coste said. “We could use it in takeoff assist, because the takeoff is the moment where you use most of the fuel. You could have a beam that provides energy during takeoff and later to also recharge the aircraft as they fly.”

Cons

A space solar power plant would have to be much larger than anything flown in space before

The orbiting solar power plant will have to be enormous, and not just to collect enough sunlight to make itself worthwhile. The main driver for the enormous size is not the amount of power but the need to focus the microwaves that will carry the energy through Earth’s atmosphere into a reasonably sized beam that could be received on the ground by a reasonably sized rectenna. These focusing antennas, Cash said, would have to be 1 mile (1.6 kilometers) or more wide, simply because of the “physics you are dealing with.”

Compare this with the International Space Station, at 357 feet (108 meters) long the largest space structure constructed in orbit to date. Space based solar power proponents all agree that how exactly such plants could be put together is still a question.

Cash says that his CASSIOPeiA concept would work also with multiple smaller plants in some types of lower Earth orbits. Having a plant closer to Earth would allow for the antenna to have a smaller size, possibly reducing the scale to one-tenth of what would be needed in geostationary orbit. On the other hand, a plant closer to Earth would be an easier target for anti-satellite missiles and might also annoy astronomers, as it would be too visible from the ground.

In every case, building a space-based solar power plant would require hundreds of rocket launches (which would pollute the atmosphere depending on what type of rocket would be used), and advanced robotics systems capable of putting all the constituent modules together in space.

This robotic construction is probably the biggest stumbling block to making this science fiction vision a reality, Cash said.

“If we can demonstrate that we can assemble smaller CASSIOPeiA satellites, 12 meters [40 feet] in diameter, using robots, then we can gradually expand to 100-meter [330 feet], 1 kilometer [0.6 miles] or 2 kilometer [1.2 miles] scales,” Cash said. “We would just need to apply more robots working in parallel. But certainly, it’s one of the key challenges.”

Converting electricity into microwaves and back is currently awfully inefficient

Airbus, which recently conducted a small-scale demonstration converting electricity generated by photovoltaic panels into microwaves and beaming it wirelessly to a receiving station across a 118-foot (36 m) distance, says that one of the biggest obstacles for feasible space-based solar power is the efficiency of the conversion process.

Microwaves slide through Earth’s atmosphere almost undisturbed, losing barely 5% of their energy during their journey from geostationary orbit, according to Airbus’ calculations. Huge amounts of energy, however, are lost already at the plant and then at the rectenna when the electricity produced by the photovoltaic panels is turned into microwaves and then back to electricity.

“The system we used in our demonstration had end-to-end efficiency of about 5%,” said Coste. “That’s not something that would be operationally viable, even though the sunlight is free. For a space-based solar plant to make sense, the efficiency would have to be around at least 20%.”

It might be turned into a weapon of mass destruction

Some worry that microwave beams in space could be turned into weapons of mass destruction and used by evil actors to fry humans on the ground with invisible radiation.

Coste admitted that if someone wanted to develop such a weapon, they possibly could. The microwave beams carrying space-based solar power, however, would be engineered from the onset to be safe.

How dangerous the beam is to human health, he said, depends on the density of the power it carries, and that could be limited by design.

“You could design the beam to be so safe that you could take a nap in it with your child and not be affected,” said Coste. “That would be at a power density level of about 10 watts per square meter. But that will require an extremely large area to collect [the energy], so we would want to have a narrower beam with higher density and some safety system around it.”

The company, he says, is looking into methods of “traffic management around the beam,” using radars and lasers to look for objects in the beam’s vicinity to stop the energy flow in case of a safety risk.

“We can engineer a system that is designed to only be pointed at a receiver and would not ever work if it pointed anywhere else,” said Coste. “We work on this concept with some big energy companies in Europe, and they don’t see it as too much of an issue, as they are used to dealing with safety problems around high-voltage power lines or gas pipelines.”

It would get damaged by micrometeorites

The vast orbiting structure of flat interweaving photovoltaic panels would be constantly battered by micrometeorites, running a risk of not only sustaining substantial damage during operations, but also of generating huge amounts of space debris in the process.

The James Webb Space Telescope, with its 21.6-foot-wide (6.5 m) mirror, received quite a few significant hits early in its operations, prompting its ground control team to adjust observing plans to avoid gazing in the direction where most of the rocks come from.

The engineers designing a possible future space-based solar power plant would certainly have to build their structure with this constant micrometeoroid influx in mind.

“For the lifecycle of the station, you have to design it in a way that it can be maintained and repaired continuously,” said Coste. “Because it’s such a large structure, you will have some defects in some panels. The ideal design of the antenna will be modular so that you could replace tiles and panels.”

Cash added that, by making the panels from the thinnest possible material, engineers can almost eliminate the generation of debris from the stricken panels.

“If we make it from some type of polymer materials, then things like micrometeorites would just punch a hole straight through,” Cash said. “We would hope that we can reduce the risk of generating debris but also the effects on the plant. If we build each of the modules to be independent of other modules, then all that happens is that a strike takes out a few elements.”

It would create a huge amount of debris at end of life

But what about the end of life? What would happen with faulty modules that had to be replaced? And what about the whole thing once it reaches the end of its life, perhaps after a few decades of power generation? Will an object 1 mile (1.6 km) across be left in geostationary orbit to slowly decay?

Wilson envisions a more sophisticated disposal procedure, which assumes that, by the time we may have space-based solar power plants, we are most likely going to see quite a bit of permanent infrastructure on the moon. Space tugs that don’t exist yet could then move the aged plant to the moon, where its materials could be recycled and repurposed for another use.

“One of the ideas for the future utilization of the moon is to use it for space launches into deeper space,” said Wilson. “We could also have some kind of recycling center there to process some of the material.”

It could contribute to light pollution

Some astronomers are concerned about the impact of such giant orbiting structures on the night sky. SpaceX’s Starlink constellation has been provoking backlash from the astronomy community ever since the company’s first satellite batches spread across the sky in the form of luminous trains.

The International Astronomical Union decried Starlink as a worse threat to astronomy than urban light pollution, with large-scale survey telescopes scanning vast swaths of the sky especially affected.

But Coste thinks that a plant in geostationary orbit, 22,000 miles away from Earth, would be barely noticable.

“From Earth, you would perceive it like a single star,” he said. “The only part of the plant that will be facing Earth is the antenna, and that doesn’t need to be light-reflecting. We could probably do something to the system to reduce the amount of light that is coming [to Earth]. I don’t think it is as big a problem as the megaconstellations.”

Cash agrees: “The whole concept [of a space-based solar power plant] is to gather and absorb as much sunlight as possible. We maintain this constant attitude, always sun-facing. And any parts which aren’t absorbing that sunlight, we can arrange them in principle to deflect the sunlight away from Earth.”

So what do you think? Should space-based solar power become a thing? Airbus appears serious about its plans, expecting to launch a small-scale demonstrator with an aerial platform in the next two years. A small-scale energy-beaming satellite might be in orbit by the end of this decade.

“We see no showstopper,” concluded Coste.