The Power of the Sun

 

One of the most common assumptions in futuristic science fiction is that energy is abundant, easily stored and easily accessed. This is necessary for spacecraft travel, matter transport, replication, controlled environments and many other, less obvious features of our more optimistic visions of the future. One avenue for fulfilling this need is to exploit the most abundant source of power we know of in our solar system: the Sun. Here we’re going to look at the science fiction of solar power, from examples of power extraction from the murky depths of Earth’s surface to the use of solar power collectors not limited by loss and scattering in our own atmosphere - solar power from space.

 

Solar power from the surface

 

The concept of sunlight as a source of energy dates back to the dawn of human civilisation, with the sun used to start fires, cook food, and focused, using mirrors, to act as a weapon by the Greeks and others. However the idea that this heat and light energy could be converted into electricity is also a surprisingly old idea.

 

An early example of sunlight being used (on the surface of Earth) to generate power can be found in Ralph 124C 41+, a novella by science fiction legend Hugo Gernsbach first published in 1925. This story focuses on the titular Ralph, a genius who is one of only a handful of people on Earth entitled to add the “+” to their identity code. At one point the characters visit a power generation station which sounds curiously familiar - at least in appearance:

 

“They alighted on an immense plain on which twelve monstrous Meteoro-Towers, each 1,500 feet high, were stationed. These towers formed a hexagon inside of which were the immense Helio-Dynamophores, or Sun-power-generators.

The entire expanse, twenty kilometers square, was covered with glass. Underneath the heavy plate glass squares were the photo-electric elements which transformed the solar heat direct into electric energy.”

 

While little more is said about power generation in this example, it is by no means unique. “Piracy Preferred”, a short story published in 1930 by John W Campbell Jr (in Amazing Stories) discusses a character’s active research into obtaining efficient electricity conversion from sunlight and reducing the necessary collecting area, before diverting into a method to extract energy from heat instead [1]. Robert Heinlein’s 1940 short story “Let there be Light” also described solar energy generation using compact panels to collect the light and perform the conversion. In this case the clay silica-based panels were originally designed to convert electrical energy to cold light - i.e. optical light with no energy wasted as infrared or ultraviolet emission - inspired by insect chemiluminescence (as seen, for example, in fireflies). Financial pressures cause the inventors to invert the process and generate power from sunlight instead [2].

 

The concept made the transition to juvenile science fiction well before it became a practicable power source in reality. Trouble on Titan, a novel for young readers by Alan E Nourse (1954) described a former convict colony on Saturn’s largest moon fighting for independence and respect. The colony had been founded to mine the rare Earth element ruthenium, which could be found in abundance on Titan [3]. In the narrative, ruthenium is a critical element in the construction of solar power conversion stations on which Earth civilisation, colonies on the inner planets, and indeed the majority of the human race had become completely dependant, giving Titanites leverage but also making Earth more reluctant to release the colony from its power.

 

A less outlandish, but still uncommon, form of ground based energy conversion can be found in the television series Thunderbirds (created by Gerry and Sylvia Anderson for TV, 1965-1966). The episode “Lord Parker’s ‘Oliday” (1966) describes a remote mountain town of Monte Bianco which is the test location for a prototype solar-thermal power station which concentrates light into a beam of heat and from there to usable electricity. As the script notes, the energy generated must also be stored in innovative new “cyclonic” batteries in order to be useful when the sun is not shining. While the residents are broadly supportive (and anticipate a boost in tourism), at least one character voices a suspicion of such marvels of modern science, claiming “It is against nature!” and with a recurring refrain of “It will be a great disaster!”

 

Unfortunately this Cassandra is proved correct when the town is shaken by a violent storm which causes the huge parabolic reflector (mirror) used to focus light to fall. The team from International Rescue are forced to race through the night to remove or refocus the dish, in order to prevent the light of the rising sun from roasting the town below (where, just to add to the tension, two of their number happen to be holidaying). In common with many Thunderbirds episodes, this narrative balances optimism about the potential miracles of science when correctly applied, against warnings against its ill-considered or negligent misuse.

 

This idea of using mirrors to concentrate light from large collection areas onto a compact energy conversion unit recurs throughout science fiction, and can find parallels in examples such as Alan E Nourse’s Martyr (short story, Fantastic Universe, Jan 1957) to Sahara (film, ????, which counts as science fiction here as the futuristic solar-thermal power station it shows does not exist). It’s also now a practicable method with numerous solar-thermal power stations in real-life operation around the world.

 

Solar collectors with ground link.

 

The dissipation of the sun’s energy in Earth’s atmosphere is a substantial challenge for solar power from the ground, as described above, though. The atmosphere is opaque to ultraviolet radiation (fortunately for us, else we’d all suffer from terminal sunburn) and also to infrared radiation (heat energy). As a result, the light that reaches the surface has already lost a lot of the power per unit area that irradiates the upper layers of the atmosphere or spacecraft in orbit.

 

A second category of science fiction regarding solar power is the narrative of energy collection in space with the resultant power supplied to the surface through some mechanism less affected by the atmosphere.

 

Influential rocket scientist Hermann Oberth made a major impact on this field in 1923 (in German, and later in English in 1929) by proposing the construction of a giant mirror in Earth orbit. This geoengineering tool could be used to redirect sunlight that would otherwise miss the Earth, either to calculated points in Earth’s atmosphere in order to manipulate the weather, or towards the surface for use in boosting temperature, agricultural productivity or other aspects of habitability for humans, particularly in polar regions. No conversion of power as such was proposed - the sunlight would merely be focussed [4] but the idea that space stations could harness the power of sunlight was a powerful one.

 

The Tom Swift novels of the 1950s (juvenile tales of a boy-genius inventor and his circle) took a refreshingly practical approach to this. Early in the series [5], the author addresses the need to power Tom’s more portable inventions (where a nuclear reactor just won’t do). The character invents a new form of battery which can be charged by sunlight in orbit and then release the energy with high efficiency when brought down to the surface by rockets.

However science fiction examples often aimed to do away with the necessity for this kind of storage and transport. Instead, energy collected in space would be broadcast to Earth via some form of beam.

 

As early as 1931, Murray Leinster published The Power Planet (novella, Amazing Stories, June 1931). The described a huge, ten-mile-wide black disk constructed in close solar orbit and always facing one side towards the Sun. This uses the temperature gradient between front and back for energy conversion and beams the resultant energy to Earth:

 

“Only forty million miles from the sun’s surface, its sunward side is raised nearly to red heat by the blazing radiation. And the shadow side, naturally, is down to the utter cold of space. There is a temperature-drop of nearly seven hundred degrees between the two sides, and Williamson cells turn that heat-difference into electric current, with an efficiency of ninety-some per cent. Then the big Dugald tubes—they are twenty feet long, on the Power Planet—transform it into the beam which is focussed always on the Earth and delivers something over a billion horsepower to the various receivers that have been erected.”

 

This idea of using a heat gradient is based on thermoelectric principles first discovered in the 1880s and still used to power spacecraft today. Probes such as NASA’s Cassini mission to Saturn use radioisotope thermoelectric generators. The isotope is used to generate heat and deep space provides a heat-sink, while the gradient drives energy conversion. In Leinster’s narrative the sun removes the need for such an artificial source. However, radioisotopes still feature: global atomic warfare on Earth (started by a never-named protagonist) threatens not just the function of the international power satellite but also its continued existence.

 

In other stories, the method of power generation is a little less clear. The short story Reason by Isaac Asimov (Astounding, April 1941) is often credited with introducing this concept of space-based solar power, although - as we’ve seen - there are contemporary and earlier examples. One of Asimov’s famous early Robot stories, it describes one of a number of space platforms tasked with collecting solar power, converting it and beaming it to collecting stations on Earth in the form of a focussed beam. In the story, one of the robots used to work in the dangers of space and solar storms, concludes that the human crew could not have manufactured it, develops a curious form of worship of the converter and also corrupts its companions. The story centres on trying to understand why and how this is consistent with the requirements of the three Laws of Robotics, but also trying to ensure the power supply doesn’t present a danger to the motherworld when a solar storm threatens the stability of the beam.

Published the month before Reason, Masquerade by Clifford Simak (Astounding, March 1941) also describes a solar power collector beaming energy to Earth, this time on the irradiated surface of Mercury (then thought to turn a constant face to the sun). From here, power is transmitted, first to stations in the twilight zone and then onwards to the other planets, from Venus to Pluto. The small crew of the power station largely ignore the presence of native Mercurians, known as Roman Candles, but the intelligent Candles are not ignoring them and present a threat to the Solar System’s power supply. As in Reason, and several of the other examples discussed here, there is no very clear explanation of how the conversion is accomplished, but the basic premise - collecting solar power and transmitting it as usable electrical energy - is clear. Curiously enough, Asimov himself wrote a story of a mining base on a tidally-locked Mercury powering itself (although not Earth) through photoelectric cells and sunlight the following year, in his story “Runaround” (1942), which featured the same two protagonists as Reason.

 

The idea of space-borne solar generators beaming abundant and free power to Earth occurred repeatedly in science fiction after such early examples, often being taken for granted as part of a future paradigm. Examples of narratives centering on such space stations include Ben Bova’s Powersat (novel, 2005, whose protagonist faces down the vested interests of the power industry, as Heinlein’s had done in Let there be light), Thunderbirds are Go episode “Bolt from the Blue” (TV animation, 2017?, which sees an Earth-orbital solar power station go out of control).

Solar power in Space

 

While transmitting power to Earth (or other human-settled planets) was, and remains, a common objective for futurists, it still requires the transmission of power through large distances and through the atmosphere, with inevitable losses along the path. A perhaps more natural use of solar power collected in space is its exploitation in space.

 

This is discovered largely by accident in The Long Way (short story by George O Smith, 1944). In this story the communications engineers of the Venus Equilateral space station want to experiment with a new power tube discovered in ruins on Mars, exploring its use for communications. Unfortunately the discoverers of this device have sold its rights to another firm: Terran Electrics. Since lawyers for the power-supply firm hamper every attempted investigation, claiming to be protecting their legal rights, the communications engineers decide to go the long way around and invent a solar energy converter to have something to barter with. They use an anode made of the “Russell Mixture” - the hydrogen and helium rich blend of gases which was proposed by astronomer Henry Norris Russell in the early 1930s as representing the chemical composition of stars, together with the novel technology and successfully create a power generation. While the idea of building orbital power-sats is initially proposed (and sold to Terran Electrics!), the Earth’s Heaviside Layer proves impermeable to the resultant beam, meaning it can only be used in space (where Venus Equilateral holds the rights).

 

A more detailed and less fantastical analysis of the economic argument for both power production and manufacturing in space was presented by Gerard O’Neill in his non-fiction book The High Frontier, which advocated for cylindrical habitats placed at the Earth-Moon Lagrange points. O’Neill envisaged both the economically-motivated export of solar power to Earth and its extensive use both to power smelting and highly technical industries (such as electronics) in the microgravity of orbit. A large body of science fiction literature was directly inspired by O’Neill’s proposals, perhaps most directly Mack Reynold’s series of novels beginning with Lagrange 5 (novel, ??) which placed a drama against O’Neill’s detailed habitat specifications. Again this rapidly became part of the background scenery of science fiction, for example in David Brin’s Sundiver (novel, 1980) where one of the major characters was raised on a solar power station associated with an O’Neill colony, Asimov’s “For the Birds” (short story, 1980) in which a spinning spherical space settlement also exports power, and Charles Sheffield’s Web Between the Worlds (1979) in which solar furnaces in orbit are used to smelt the material for space elevator construction.

 

Indeed the exploitation of solar power in space, extending to the largest scales, has been a feature of science fiction since its early days. Notably, Olaf Stapledon’s Star Maker (1937) describes civilisations which have englobed their sun in order to capture all its energies - presaging the spheres of energy harvesting popularised by Freeman Dyson in the 1960s. Dyson spheres in fiction may simply form a spherical living surface (although this calls for materials with unobtainable properties) but often mix living surface with solar power generator collecting area, as seen for example in The Bowl of Heaven by Larry Niven and Gregory Benford (novel, ??). Indeed, the ability to exploit all a star’s energy is now recognised as stage II of the Kardashev Scale of hypothesised advanced civilisations (we’re at about 0.5 on the Kardashev Scale).

Practical problems.

 

As many of these examples demonstrate, there was a real optimism for the potential of solar power, and particularly space-based solar power, amongst science fiction writers. This entended across decades, with relatively little diminution, despite the failure of expected space habitats to appear. Even the more conservative and technically trained science fiction writers saw their advent as inevitable. Writing in non-fiction book “A Choice of Catastrophes” (1980, pg 320) he confidently announced that “… by 2020 not only will there be nuclear fusion power stations in operation, but the first few solar power space stations will be in operation.”

 

The same enthusiasm exists in speculative technical disciplines. Ground-based solar power, both in the form of photovoltaic solar panel farms and in the form of solar-thermal mirror arrays focussing light on a concentrating tower, are established technology. Space mirrors have been demonstrated in orbit and regularly recur as a suggestion for improving crop yields, with serious investigations undertaken by NASA and other organisations. Space-based solar power continues to attract investment and discussion as a commercially viable prospect, all the more so in recent years as the dangers of climate change have been recognised. However, achieving practicable space-based solar power (like nuclear fusion) remains a consistently predicted 30 to 50 years in the future.

 

Part of this is due to changes in political will, perceptions of acceptable risk and expectations regarding workplace safety. We now have a better understanding of just how damaging working in space is to the human body, and less tolerance for deaths in the construction and development of new technology. Part is due to resistance from established energy industry lobbies, as predicted by Heinlein, Bova and others [6]. Some of the other problems associated with solar power stations are purely practical, and these have also been highlighted in science fiction.

 

The issue of the low efficiency of solar power, both in the conversion of sunlight energy to electricity and the diffusion of light through the atmosphere, was a common theme in many of the early stories - although these tended to assume such limits could be overcome using novel (and hence unexplained) technologies. While we now have knowledge of laser technology, this was in its infancy in the mid-twentieth century, and building a power beam that would allow the energy to be collimated (narrowly focussed without dissipating) and transported over large distances remains a substantial technical challenge [7].

 

One advantage of space-based collection, particularly in closer orbits than the Earth, is that the higher energy flux available for collection somewhat mitigates for losses along the line of sight. This means that a spreading of the power beam may or may not be a problem - and could even be an advantage. Indeed, in The Power Planet, Leinster commented that:

“At the Power Planet it was a hundred yards across, and it was luminescent even in emptiness. By the time it reached Earth it was a full eight thousand miles across, so that Dugald-beam receivers anywhere on the surface could tap its power.”

 

Science fiction writer and professional space technologist Jerry Pournelle, writing a non-fiction article in his book The Endless Frontier (which mixed short fiction with factual material), also advocated diffuse and low power projected energy beams, such that they would not present a substantial danger to those below. Indeed, he suggested that microwave antennae could be strung above large areas of pasture or agricultural land, collecting low intensity broadcast power from above twenty-four hours a day without impeding the previous use of the land. This was in contrast to the filk [8] song “Home on Lagrange” (lyrics by Bill HIggins and Barry Gehm) which followed the article and contained the memorable verse:

 

“You don’t need no oil, nor a tokamak coil,
Solar stations provide Earth with juice.
Power beams are sublime, so no one will mind
If we cook an occasional goose”

 

Indeed, in most stories, keeping such a power beam narrow and focussed is a priority, not just to reach Earth from elsewhere in the solar system with minimal power losses, but often to deliver energy to a specific and rather small collecting station on Earth’s surface. In Asimov’s Reason, for example, a real concern was that the solar storm would cause the energy beam from the power station to Earth to wander, potentially causing devastating damage. While this beam was travelling from a substantial distance away, the same issue can occur from as close as Earth orbit. Animated series Thunderbirds Are Go also explored this in the episode “Bolt from the Blue” when a commercial orbital power station (being commanded by a sales executive rather than an engineer) malfunctioned and lost collimation, sending “positively charged plasma bolts” down into the atmosphere, crippling a passing aeroplane [9].

 

At least in these cases, the potential damage caused by the beam was accidental. While radiation risks in the form of space weather is a serious concern for any space station (both in terms of electronic damage and the impact on any crew), it could be mitigated by a temporary suspension of operation. And while human error is always a risk, that is equally true of ground-based power generation. Of more concern would be the weaponization of any such energy beam from space - as demonstrated by the giant orbital mirror system Icarus, which was deliberately targeted on the Korean Demilitarized Zone in the James Bond film Die Another Day [10].

 

Solar power is now a fact of life, with photovoltaic cells far exceeding the efficiency of those possible in the mid twentieth century. Space mirrors have been demonstrated, as has wireless power transfer - both in the near field and over reasonable distances. On the other hand, many of the problems associated with space-based solar power, in particular the efficiency and control of the power beam, remain as unresolved as they were when early science fiction writers first considered them. As with so many areas of human space exploitation, the optimism shown by science fiction writers and futurists in the late twentieth and early twenty-first centuries has proven sadly unjustified. However investment in this field, both from research agencies such as NASA, the Chinese National Space Administration or Japanese JAXA, and from the private sector is substantial. Improvements in technologies for autonomous control of satellites are ongoing and could improve the prospects for realising orbital solar power stations without the huge expense of supporting human operators.

 

Solar power has come a long way from the early days. Photovoltaics are a maturing technology. The technology required for space-based energy collection is certainly plausible, if the political will and huge initial financial investment can be found. It is entirely possible that, like solar energy generation technologies on the ground, space-based solar power may, in coming years, move from the speculative exploration and creative freedom of science fiction into the realm of everyday life. One might even say that, where solar power is concerned, the future is bright.

“The Power of the Sun”, Elizabeth Stanway, Cosmic Stories. January 2025.

Notes:

 

[1] Of course, Campbell’s proposal casually defies the second law of thermodynamics in the process. Piracy Preferred was later incorporated into Campbell’s fixup novel The Black Star Pases (1953).

 

[2] As with many of Heinlein’s works, “Let there be light” makes for a painful read given its assumptions regarding science, gender roles and relationships. The biochemist initially proposing the project is a woman, while the physicist who realises it is male, and their interactions are very much written from a male perspective typical of its times.

 

[3] We have no evidence that Titan is rich in Ruthenium but Nourse’s narrative fits into a tradition both of settling Titan and of exploiting Solar System resources to supply needs on Earth. There is also no proposed or active solar power system in which ruthenium is used, indeed it occupies the wrong part of the periodic table to be useful in current technologies.

 

[4] Science fictional examples of space-mirrors used for environmental engineering include, for instance, Completely Automatic by Theodore Sturgeon (short story, Astounding, Feb 1941), in which such mirrors are used to render Saturn’s moon Titan habitable, as a “soletta” in Kim Stanley Robinson’s Mars Trilogy, and the James Bond film Die Another Day (2002), in which the Icarus project aims to boost agriculture in cold regions. There are many others, and variants including Isaac Asimov’s The Big Sun of Mercury, in which hyperspace is used to redirect light instead. But this is a slight digression from power generation!

 

[5] The 1950s series of space- and nuclear-focussed adventures technically features Tom Swift Jr, son of the original from the first Tom Swift novel series which started in the 1910s, and was written pseudonymously under the penname Victor Appleton II rather than just Victor Appleton.

 

[6] The James Bond series provides another example of resistance to solar energy: The Man with the Golden Gun in the eponymous film (??) was an assassin employed by the energy industry to suppress the discovery of a new solar power converter known as the solex agitator.

 

[7] The same problem afflicts science fiction which projects power to spaceships with similar beams, as in Theodore Sturgeon’s Completely Automatic, or the comic series Dan Dare. In these the power supply is as often nuclear as solar in derivation but the problem of broadcasting it remains.

 

[8] Filk is a long-standing tradition of amateur vocal music inspired by science fiction or fantasy themes, often beginning with changing the words of familiar tunes, and often presented at science fiction conventions. The song lyrics presented in The Endless Frontier are set to the tune of “Home on the Range” and printed together with the suggested guitar chords.

 

[9] With a certain inevitability, given the premise of the show, the plane in question was carrying both a child and a giant panda who ended up in need of rescue. Thunderbirds Are Go should also be given an honorary mention for the episode “Recharge” which featured a power station drawing power from the aurora (i.e. charged particles energised by the solar wind and channelled by Earth’s magnetic field). Unfortunately, this has even a lower energy density than sunlight.

 

[10] Again, the Anderson universe provides an example here, with the Mysterons taking over a newly launched solar power satellite with the aim of using it for destruction in the 1993 Captain Scarlet pop-up book for children Solar Flare, written by Graham Marks.

The views and opinions expressed here are those of the author and not necessarily those of the University of Warwick. Images have been sourced online and are used here for commentary and criticism. Credit (and blame) for the dreadful final pun belongs entirely to Prof. Jan Eldridge.

First story in Towering Yarns (Kindle): space elevator as prerequisite for solar power. (“Victor” - Christian W Smith. Slightly awkward story of British professor and wife rescuing Zimbabwean genius from poverty).

Blade Runner 2049?

Frederick Pohl - The Cool War

Solar Panels on Tie Fighters