It sounds like science fiction: giant solar power stations floating in space that beam down enormous amounts of energy to Earth. And for a long time, the concept – first developed by the Russian scientist, Konstantin Tsiolkovsky, in the 1920s – was mainly an inspiration for writers.
A century later, however, scientists are making huge strides in turning the concept into reality. The European Space Agency has realised the potential of these efforts and is now looking to fund such projects, predicting that the first industrial resource we will get from space is “beamed power”.
Climate change is the greatest challenge of our time, so there’s a lot at stake. From rising global temperatures to shifting weather patterns, the impacts of climate change are already being felt around the globe. Overcoming this challenge will require radical changes to how we generate and consume energy.
Renewable energy technologies have developed drastically in recent years, with improved efficiency and lower cost. But one major barrier to their uptake is the fact that they don’t provide a constant supply of energy. Wind and solar farms only produce energy when the wind is blowing or the sun is shining – but we need electricity around the clock, every day. Ultimately, we need a way to store energy on a large scale before we can make the switch to renewable sources.
Benefits of space
A possible way around this would be to generate solar energy in space. There are many advantages to this. A space-based solar power station could orbit to face the Sun 24 hours a day. The Earth’s atmosphere also absorbs and reflects some of the Sun’s light, so solar cells above the atmosphere will receive more sunlight and produce more energy.
But one of the key challenges to overcome is how to assemble, launch and deploy such large structures. A single solar power station may have to be as much as 10 kilometres squared in area – equivalent to 1,400 football pitches. Using lightweight materials will also be critical, as the biggest expense will be the cost of launching the station into space on a rocket.
One proposed solution is to develop a swarm of thousands of smaller satellites that will come together and configure to form a single, large solar generator. In 2017, researchers at the California Institute of Technology outlined designs for a modular power station, consisting of thousands of ultralight solar cell tiles. They also demonstrated a prototype tile weighing just 280 grams per square metre, similar to the weight of card.
Recently, developments in manufacturing, such as 3D printing, are also being looked at for this application. At the University of Liverpool, we are exploring new manufacturing techniques for printing ultralight solar cells on to solar sails. A solar sail is a foldable, lightweight and highly reflective membrane capable of harnessing the effect of the Sun’s radiation pressure to propel a spacecraft forward without fuel. We are exploring how to embed solar cells on solar sail structures to create large, fuel-free solar power stations.
These methods would enable us to construct the power stations in space. Indeed, it could one day be possible to manufacture and deploy units in space from the International Space Station or the future lunar gateway station that will orbit the Moon. Such devices could in fact help provide power on the Moon.
The possibilities don’t end there. While we are currently reliant on materials from Earth to build power stations, scientists are also considering using resources from space for manufacturing, such as materials found on the Moon.
Another major challenge will be getting the power transmitted back to Earth. The plan is to convert electricity from the solar cells into energy waves and use electromagnetic fields to transfer them down to an antenna on the Earth’s surface. The antenna would then convert the waves back into electricity. Researchers led by the Japan Aerospace Exploration Agency have already developed designs and demonstrated an orbiter system which should be able to do this.
There is still a lot of work to be done in this field, but the aim is that solar power stations in space will become a reality in the coming decades. Researchers in China have designed a system called Omega, which they aim to have operational by 2050. This system should be capable of supplying 2GW of power into Earth’s grid at peak performance, which is a huge amount. To produce that much power with solar panels on Earth, you would need more than six million of them.
Smaller solar power satellites, like those designed to power lunar rovers, could be operational even sooner.
Across the globe, the scientific community is committing time and effort to the development of solar power stations in space. Our hope is that they could one day be a vital tool in our fight against climate change.
This article is republished from The Conversation under a Creative Commons license. Read the original article.
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If the distance for beaming the energy back to Earth wouldn't hinder the project, then building the sun energy collectors on the moon could be the best solution.
Using the moon materials theoretically, the whole Moon surface facing the Earth could be covered. ( actually, the whole moon could be covered and the energy cabled to any spot from where the transfer to the Earth would be possible. )
If the process of material mining and the collectors manufacturing could be automated then the entire cost of the project will be 'just' with the minimum basics needed to be transferred to the Moon.
It does not make sense that they should develop this technology, which as you say adds complexity and weight, if it is also more expensive overall. The stated reason is that it saves money over time by not having to build all-new boosters for every launch. While the hardware for an individual launch may be more expensive, the ability to re-use that hardware saves money for the ongoing program, and all these companies have ongoing programs for offering launch services. And that's a reason why launch costs are decreasing, which was the original question.
Most basically, we already have a space-based platform on which to collect solar energy: the Earth. And we are already placing solar panels on that platform at exponentially increasing rate and exponentially decreasing cost per kilowatt-hour. According to the International Energy Agency, in favorable locations solar power is already the “cheapest electricity in history” ( https://webstore.iea.org/world-energy-outlook-2020 ). Production of solar power on Earth occurs only during the day, but this approximately matches daily power demand and utilities are already fielding storage technologies to time-shift solar output as needed (flow batteries, lithium ion batteries, molten-salt thermal storage, and other technologies, all of which are sliding down cost-learning curves as experience grows and deployment ramps) -- and time-shifting is only needed at very high levels of supply penetration in any case. Plus, wind turbines run in the dark.
Any space-based form of solar power – with its launch systems, orbital power transmitters, huge centralized ground receivers, and the like – would, by the time it was deployed in 2050 or beyond, have to compete in cost per unit of energy generated ($/kWh) not with today’s already cheapest-of-them-all solar and wind but with the even lower costs these sources (and storage) will have achieved by that far-distant time. It would take divine intervention, lots, to make space-based power competitive under these conditions.
As a measure of the quality of thinking going on in this article, consider the following bit: “Researchers in China have designed a system called Omega, which they aim to have operational by 2050. This system should be capable of supplying 2GW of power into Earth’s grid at peak performance, which is a huge amount. To produce that much power with solar panels on Earth, you would need more than six million of them.”
Two of the numerous problems with this blob of pseudo-technical codswallop:
1) 2 GW is not a “huge amount” of power: it is noise-level compared to the 1,123 GW of wind and solar that, the International Energy Agency estimates, will be deployed globally in just the next 3-4 years: https://www.iea.org/reports/renewables-2020
2) Conjuring with context-free big numbers like “six million” is silly. The bottom line is not how many panels are needed but how much the energy ends up costing, and, as noted above, there is zero chance that energy from outer space will ever cost less than energy from ground-based panels that one can access via pickup truck. Or on foot. Which are already cheaper than oil, gas, coal, most wind, or newbuild nuclear ( https://www.lazard.com/perspective/lcoe2020 ). And are getting cheaper all the time.
Of course, if spaceflight is one’s religion, anything that would involve lotsa, lotsa spaceflight, no matter how hare-brained or costly, will seem worthy of promotion. But the rest of us need not treat such effusions as serious engineering visions.
Just one issue I have always wondered about:
Many incorrectly state that solar is only good during the day, and you brought up some examples of storage, except my favorite. Since you seem to be well versed in this aspect of energy generation, you might be able to address this issue, hopefully with none of the codswallop often found in other treatments.
Solar power can be used to create one of the most useful energy sources on the planet: molecular hydrogen. This gas can be produced by electrolysis of water, and used directly, or compressed and shipped as a liquid all over the world. Hydrogen powered fuel cells are very efficient and the pollution is practically zero since it gives back what it was derived from - water.
Any chance of this playing a major role in "solar power by other means"? We could all have fuel cells to power our homes, etc. And no more black-outs from storms, etc.
But is it feasible? Storage batteries, etc. clearly will work, but which is going to be the most efficient and widely practical. Many are not easily portable, very important for any "universal" energy source. H2 fuel cells sound like the answer. Super clean, and very efficient.
Many think of the Hindenburg disaster whenever hydrogen safety issues come up. But burning petrol is much more hazardous than burning H2. The petrol falls to the ground and burns everything around it, until it is gone. Burning H2 rapidly rises from the ground, limiting damage.
If we can transport that horrible petroleum, and its liquid fuel products all over the world, by ship, rail and truck, why not liquid hydrogen?!