Space Energy Options

NASA SolarDisk
Solar Disk - Credit: NASA

 

In current discussions about transiting from fossil fuels to some other alternative energy source, it is surprising that energy from space, specifically Space-Based Solar Power (SBSP) , a technologically feasible idea that was introduced as the Solar Power Satellite by Peter Glaser in 1968 [1] and patented in 1973, is rarely considered or even discussed as a possible alternative to terrestrial energy sources. The standard objection to SBSP has been the initial cost to implement such a space power system. [2] This cost is often unfairly compared to costs of terrestrial energy solutions which are highly subsidized by governments. A fair comparison considered in the context of the increasing demand for CO2-neutral energy and the value of the global energy market by the year 2050, this objection should have lesser relevance as terrestrial energy alternatives prove to be insufficient, impractical, expensive or undesirable and the magnitude of Energy Dilemma becomes apparent.

Peter Glaser described the basic SPS concept in terms of actual technological capabilities. Intriguingly, several science-fiction authors had presented related schemes since the 1940’s. In particular, Isaac Asimov had a space station near the Sun collecting energy and transmitting it to various planets using microwave beams in his short story “Reason” [3].

Following Glaser’s publication, several technical studies assessed the feasibility of supplying Earth with solar power from space. To date, the most extensive study remains the “Satellite Power System Concept Development and Evaluation Program,” conducted from 1977 to 1981 by the (US) Department of Energy (DoE) and NASA, with a $19.7 million budget. [4] Ralph Nansen, at the time with the Boeing Corporation, participated in this study. In his book: Sun Power: The Global Solution for the Coming Energy Crises (1995), he writes that the study had come to a conclusion that Space Solar Power relying on large reusable rockets and automated assembly systems in orbit was technically feasible. Nansen writes, had the project gone forward, an investment of $2 trillion would have saved the United States $22 trillion by 2050 and this would have adverted the energy crises we are now facing forty years later.[5]

More recently, a study by the International Academy of Astronautics (IAA) – completed in 2011 [6] and subsequently published in the book The Case For Space Solar Power (2014) by the IAA study’s lead author John Mankins [7] – realistically describes how a SPS located in Earth orbit would use the latest technologies and be built by robots out of modular components – a concept that has both economic and maintenance advantages.

There are a number of technological approaches to building the optimal SPS. These range from very large structures placed in Geosynchronous orbit (GEO) to smaller satellites in Middle Earth Orbit (MEO) and in Low Earth Orbit (LEO). The size and mass of the satellite and the choice of orbit will have much impact on the overall efficiency and cost of an eventual SPS system. In addition to the aforementioned DoE/NASA study, various approaches to SPS are discussed in detail in these seven books about Space-Based Solar Power:

  • Frank P. Davidson, L.J. Giacoletto, & Robert Salked, Eds. (1978) Macro-Engineering and the Infrastructure of Tomorrow. AAAS Selected
    Symposium 23, Westview Press, Boulder (CO), 131-137

  • P Glaser, F Davidson, & K Csigi, (1998) Solar Power Satellites, Wiley

  • Don M. Flournoy (2011) Solar Power Satellites, Springer

  • Ralph Nansen, (1995, 2012) Sun Power: The Global Solution for the Coming Energy Crisis, Ocean Press 1995, Nansen Partners 2012

  • Ali Baghchehsara and Danny Jones, (2014) Electric Space: Space-based Solar Power Technologies & Applications, Amazon

  • John Mankins, (2014) The Case for Space Solar Power, Virginia Edition Publishing LLC

  • Michael Snead, (2019) Astroelectricity, Spacefaring Institute LLC

For comparison with terrestrial energy alternatives, one may build on the 5-GW power level used e.g. in the DoE/NASA reference study. The power generated by the orbital plant must cover the losses in the transmission chain: (i) in the conversion from DC electrical to microwave power, (ii) in relation with the beam’s space and absorption losses, and (iii) with the microwave capture and conversion to AC power at the ground “rectenna” (rectifying antenna). One also has to account for the time the station passes through the Earth’s shadow (<1% for a geostationary orbit). For 1 TW of continuous power, then, some 202 solar power satellites would be necessary. Scaling this to meet humanity’s energy needs, about 3,030 of such power plants would be necessary to deliver 15 TW, which is approximately what is needed to replace fossil fuels today. Twice this number would be required to provide 30 TW of continuous clean solar power in the year 2050.

Solar Power from the Moon

In the mid-1980s, David Criswell introduced a significant variation of the SPS concept called the Lunar Solar Power (LSP) System. Instead of building the photovoltaic system in Earth orbit using materials transported from Earth, he proposed a potentially more efficient approach by using an existing orbiting platform – the Moon – for the location of the solar collectors and to use lunar materials for their construction. Criswell contends that generating power from the Moon would be at least 50 times more cost efficient than competing approaches such as large solar arrays on Earth or solar power satellites deployed to orbit about the Earth either from the Earth or from the Moon. The sunward hemisphere of the Moon continuously receives 13,000 TW of solar power. In addition, all of the main resources for power generation – reliable solar power, lunar real estate, and appropriate materials – are readily available on the Moon [8]. Thus, instead of sending tons of materials from Earth into space at great environmental and financial cost, and constructing these enormous and complex power satellites in orbit, one would send a small team of humans accompanied by the necessary robots to the lunar surface to carry out the job on site.

The primary material necessary for the manufacture of photovoltaic collectors is silicon, which, as on Earth, is in great quantity on the Moon. The solar converters would be thin-filmed photovoltaics made out of lunar glass. Robots would mine the lunar soil for silicon and the photovoltaics would be manufactured in an automated factory constructed for this purpose. The basic technology for manufacturing photovoltaics with a conversion efficiency factor of less than 10% already exists and the engineering aspects are typical of major construction techniques. Of course these activities would be carried out in a new environment but thanks to Apollo, there exists substantial information about the lunar environment. The photovoltaics would be mounted on a grid that would also be constructed from of lunar materials.

Criswell estimated that within 10 years from startup, a LSP system could be providing 50 GWe (Gigawatt electric) per year of electric power and a small scale 100 GWe demonstrator system could show a net profit within 10 years. This would be steadily increased in average yearly installments of 560 GWe/year over a 30 year period eventually reaching a 20,000 GWe or 20 TWe which, at 2 kW per person, is considered as a minimum sustainable energy level for a population of 10 billion if the energy is equally distributed. In 2002 Criswell stated: “Prosperity for everyone on Earth by 2050 will require a sustainable source of electricity equivalent to 3 to 5 times the commercial power currently produced.” [9] 3 kW per person would equal the 30 TW currently projected for an expected population of 10 billion in the year 2050.

Following in Criswell’s footsteps, the Shimizu Corporation in Japan has proposed the Luna Ring – a gigantic, 400 km-wide and 11,000 km-long mirrored structure positioned on the lunar equator which would capture solar energy and beam it back to Earth with lasers. [10]

Helium-3 Astrofuel

Helium-3 is sometimes referred to as Astrofuel. Helium-3 is transmitted with the solar wind, but Earth’s magnetic field pushes the isotope away so that only extremely small quantities of it are found on Earth. It is seen as an ideal isotope for nuclear fusion reactors on Earth once these become operational since helium-3 reaction produces no radioactive byproducts. Thanks to the Moon’s negligible magnetic field, it is estimated that up to 1,100,000 metric tonnes of helium-3 have been deposited in the lunar regolith, however in concentrations of less than about twenty parts per billion.

Extracting helium-3 from the lunar regolith will require the mining and processing of hundreds of millions of tons of regolith. This would also require a very large lunar operation which would also depend on large amounts of energy such as Lunar Solar Power to heat the regolith to a temperature of about 600 degrees centigrade. It has been estimated that 1 million metric tonnes of helium-3, reacted with deuterium, would generate about 20,000 terawatt-years of thermal energy. To put this into perspective, 25 tonnes of helium-3 would power the United States for one year at current consumption levels [11].

This technology may become viable once nuclear fusion has been demonstrated at a commercial level and eventually, there may be some synergies once this technology advances. The most comprehensive book about mining helium-3 is “Return to the Moon” by Apollo 17 astronaut and geologist Harrison Schmitt [12]. Once humanity has become a true spacefaring species, helium-3 could perhaps be easier obtained from the four giant gas planets, Jupiter, Saturn, Uranus and Neptune; all of which have very large amounts of helium-3 in their atmospheres [13]. The movie “Moon” (2009) directed by Duncan Jones is about an astronaut on the Moon who has been managing the mining facilities extracting helium-3 from the lunar surface to be sent to Earth for use in fusion power generators.

Helium-3 and Lunar Solar Power are discussed in some detail in the following:

  • John S. Lewis, (1996) Mining the Sky, Basic Books

  • Dennis Wingo, (2004) Moonrush: Improving Life on Earth with the Moon’s Resources, Apogee Books Space

  • Charles Proser (ed.), (2005 – DVD) Gaia Selene, Celestial Mechanics

  • Harrison Schmitt, (2006) Return to the Moon, Praxis Publishing

  • Robert Zubrin, (2019) The Case for Space: How the Revolution in Spaceflight Opens Up a Future of Limitless Possibility, Prometheus Books

  • Leonard David, (2019) Moon Rush: The New Space Race, National Geographic

Environmental Considerations of the Space Energy Options

Energy from space would be a very “green” technology when compared with terrestrial energy alternatives, especially if it developed within an international collaborative context. As mentioned above, the land area necessary for continuous baseload ground solar or wind is substantially larger than that required for nuclear power generation. In addition, the intermittency issue for ground solar or wind requires a massive storage capacity to insure continuous 24/h day electrical power. In comparison, the mass of a Solar Power Satellite and its rectenna (receiving antenna) would be 10-20% less than an equivalent ground based photovoltaic system with its storage system. [14] Before lunar resources become available for fabricating space power system off-Earth, the power satellites will need to be constructed on Earth and launched into orbit. This will require a fleet of reusable launchers, ideally a single-stage-to orbit launch vehicle fueled by liquid oxygen (Lox) and liquid hydrogen (LH2) as the waste would be mostly water vapor.

Such launch vehicles are under development and conceivably an international consortium of nations could accelerate this development. As to the “thermal burden” or the warming effect of energy generation, analysis has shown that 15 TW of power from space would contribute less than 0.006 o C to increasing Earth’s temperature. Compared to the temperature increased caused by power production from fossil fuels, this amount is extremely small. [15] As to the safety of beaming power to earth from space, microwave transmission is preferable to laser transmission which eliminates the weaponization aspect and the potential danger laser light on eyes. As to the environmental effects of electromagnetic microwave exposure on flora and fauna, the International Academy of Astronautics study indicated a maximum allowable energy intensity in a wireless power transmission should be less than the intensity of full summer sunlight at the equator – in other words, less than 1,000 watts per m2. The acceptable standard could be set and regulated by an international consortium.

Economic Considerations of the Space Energy Options

The standard criticism for deploying a space power system has been the initial cost, especially the cost of launching massive amounts of mass into Earth orbit. With a dedicated international effort resulting on the mass production of a specific re-usable launch system as well as mass-producing and automatizing the manufacturing process of the space power systems, economic efficiencies can be expected. At the moment these space systems are more-or-less custom built due to the small size of the space power generation market applied to supplying individual satellites and the International Space Station with electrical power. The eventual use of lunar materials and space manufacturing could substantially reduce costs further. Once these efficiencies are achieved, the actual cost of space energy systems can be realistically compared to terrestrial energy alternatives.

As pointed out when discussing the LCOE and LACE costs of energy production, there are additional governmental policies, subsidies and tax issues involved in determining the revenue required to build and operate a power generating system over a specified cost recovery period and the revenue available to that generator over the same period. This will apply to space power systems as well. However, if terrestrial energy alternatives cannot be sufficiently scaled to replace fossil fuels which are concurrently becoming critically depleted, then the argument based purely on the initial development costs of deploying a viable space power system becomes less relevant. Humanity needs a plentiful and inexhaustible source of clean energy to maintain and sustain civilization. Without this, civilization will collapse.

Advantages and Disadvantages

The U.S. National Space Society has complied a list of advantages and disadvantages of Space Solar Power. [16]

Advantages

  • Unlike oil, gas, ethanol, and coal plants, Space Solar Power does not emit greenhouse gases.

  • Unlike coal and nuclear plants, Space Solar Power does not compete for or depend upon increasingly scarce fresh water resources.

  • Unlike bio-ethanol or bio-diesel, Space Solar Power does not compete for increasingly valuable farm land or depend on natural-gas-derived fertilizer. Food can continue to be a major export instead of a fuel provider.

  • Unlike nuclear power plants, Space Solar Power will not produce hazardous waste, which needs to be stored and guarded for hundreds or thousands of years, nor is it an easy target for terrorists and cannot be weaponized.

  • Unlike terrestrial solar and wind power plants, Space Solar Power is available 24 hours a day, 7 days a week, in inexhaustible quantities. It works regardless of cloud cover, daylight, or wind speed.

  • Unlike coal and nuclear fuels, Space Solar Power does not require environmentally problematic mining operations.

  • Space Solar Power will provide true energy independence for the nations that develop it, eliminating a major source of national competition for limited Earth-based energy resources.

  • Space Solar Power will not require dependence on unstable or hostile foreign oil providers to meet energy needs, enabling us to expend resources in other ways.

  • Space Solar Power can be exported to virtually any place in the world, and its energy can be converted for local needs — such as manufacture of methanol for use in places like rural India where there are no electric power grids. Space Solar Power can also be used for desalination of sea water.

  • Space Solar Power can take advantage of our current and historic investment in aerospace expertise to expand employment opportunities in solving the difficult problems of energy security and climate change.

  • Space Solar Power can provide a market large enough to develop the low-cost space transportation system that is required for its deployment. This, in turn, will also bring the resources of the solar system within economic reach.

Disadvantages

  • High Development Costs. While development costs will be substantial, seen in the context to addressing the Energy Dilemma and the Climate Emergency with no viable and scalable terrestrial energy alternatives, the Space Energy Option is the only viable near term energy solution. A concerted commitment to the development of the Space Energy Option would surely lead to cost efficient strategies, measures and technologies that would lower the costs and some of these will be explored on this website as the project develops. In any case, the ultimate cost of of implementing the Space Energy Option always needs to be compared to the cost of not developing it

  • Contrary Political Agendas. Addressing the Energy Dilemma and the Climate Emergency with a viable space-based solution appears to be counter to proposed energy-use quotas on people and nations that are currently being promoted and implemented in programs such as the United Nations Agenda 2030, the Paris Climate Agreement, the World Economic Forum's Fourth Industrial Revolution and the Bank for International Settlements' Innovation BIS 2025. Other corporate, environmental and political organizations are adopting these programs as a means to reset the prevailing economic system. Indeed, those in charge of these organizations are surely aware that fossil fuels are finite, approaching their depletion limits and cannot be feasibly replaced with any terrestrial energy alternative, yet rely on terrestrial solutions for addressing the Energy Dilemma.

Civilization's Future Energy Needs


Recently published studies by the International Academy of Astronautics (IAA) [18]and the World Energy Council (WEC) [19] provide a glimpse into the future energy needs of our civilization. These organizations report that the the global population in the year 2050 will be around nine billion people and global economic production will be at a minimum twice as high as today. By the end of the century, economic progress will require a four-fold increase in annual energy use. By 2050, China and India are likely to replace Europe and North America as the largest economic spheres, while the population will grow fastest in Africa. Long-term projections for global economic growth will average about 3% per year in the developed countries and will be more in the developing and emerging economies.

What does this mean for the world in the areas of energy supply, carbon dioxide (CO2) emissions and energy resources?

The recent assessment (2013) by the Intergovernmental Panel on Climate Change (IPCC) has reinforced the dire predictions of its earlier reports. One of their key findings was that humanity needs to emit no more than one trillion tons of carbon in order to stand a good chance of limiting global warming to 2 °C. They predict that a warmer planet will lead to a rise in sea levels, ocean acidification, a shift in food productions regions and more migration pressures. Quite simply, these trends consitute a Climate Emergency which could compromise the sustainability or our civilization and likewise, the survival of our species.

The report by the International Academy of Astronautics (IAA) states that if CO2 emissions into the atmosphere are to be constrained by 2100 some 90% of all energy used must be from renewable or nuclear sources. However, the World Energy Council (WEC) report indicates that our primary energy source in 2050 will be still be derived mostly from hydrocarbons. As much as 80% in the their free-market scenario and still 60% in their government regulated scenario which relies on stronger use of “CO2 free“ technologies, and the deployment of carbon capture and storage (CCS) technologies in the generation of electricity. However, this will raise the cost of energy production by approximately 33% which could perhaps be tolerated in the developed countries but would be very negative for the developing economies of the world.

As far as alternative, terrestrial renewable resources such as hydropower, geothermal, terrestrial photovoltaic and wind, the IAA report asserts that energy production from these sources will remain a modest fraction of the total energy picture as these technologies are unlikely to provide the huge amounts of new and sustainable energy that will be needed in the coming decades.

Thus, we have an Energy Dilemma that needs to be solved. In order for the global economy to increase by incorporating the less developed regions of the world, it will need substantially more energy than is being produced and used today. The primary source of energy in the near term will continue to be fossil or hydrocarbon based as these are less expensive but their use results in higher CO2 emissions. This will not only bad for the climate but is accompanied by geopolitical competition and conflicts over the remaining resources. Nuclear energy sources also have unsolved political and environmental issues as well as high start-up cost and also cannot be scaled to replace fossil fuel use. Likewise, alternative terrestrial renewable energy sources, though desirable, cannot scale to meet our future energy demands.

Thus, if there was a viable environmentally clean energy option that has the potential to meet all of our civilization's future energy needs and even avoid geopolitical conflicts over resources and territory, then this should be the obvious choice that humanity wouldsoon want to make. Fortunately, there is an alternative which is discussed in the next section.

Next Steps

Although the engineering and logistical challenges would be formidable, except for the case of helium-3 fusion power, no new technology needs to be invented and no scientific breakthroughs are necessary for the SBSP/LSP approaches. The generation of electrical power in space and the transmission of power via microwaves have been demonstrated. Additional research is needed to control and direct these low-intensity beams over the required distances of space. The logistics of establishing and supplying a manned lunar base community – though a large task – is comparable to similar large scale engineering projects that have been accomplished on Earth.
It should be pointed out that the money spent to finance and construct a SPS/LSP system would be spent on Earth and flow through the global economy. Considering the value and ever increasing demand for energy, the potential revenues of such a clean energy producing system would certainly be immense and the initial investment quickly amortized. The real challenge of implementing this system is this initial financial investment and gaining the public’s confidence in the system.

China has recently signaled its interest in developing an Earth-Moon economic zone by 2050 and mining of helium-3 may appears to be the economic motivation to do so [17]. If any one nation dominates and the controls the source of energy powering the world economy this will obviously become a reason for conflict. Also, power generation stations in orbit or on the Moon would become targets in case of war and this aspect would lead to further militarization of space activities and the fallout of any large scale destruction of space assets could result in making the space environment unusable and in the worst case, forever trapping humanity on its home planet. Therefore an international consortium of nations dedicated to jointly developing any of the Space Energy Options would seem to be the way forward. This concept is discussed in the article: GEEO – Greater Earth Energy Organization [20].

References

  1. Peter E. Glaser, Power from the Sun: Its Future, Science, 22 November 1968
  2. Space-Based Solar Power for Energy Transmission, Nanalyze.com, April 13, 2020
    https://www.nanalyze.com/2020/04/space-based-solar-power-energy-transmission/ Accessed 24.4.2020
  3. Isaac Asimov (1941). Reason. Astounding Science-Fiction [04], 33-45; also in: Isaac Asimov (1950). I, Robot. Gnome Press.
  4. Satellite Power System Concept Development and Evaluation Program, NSS Archive
    https://space.nss.org/satellite-power-system-concept-development-and-evaluation-program/ Accessed 10.4.2020
  5. Ralph Nansen, (1995/2012) Sun Power: The Global Solution for the Coming Energy Crisis, Amazon Kindle location 391, Ocean Press 1995, Nansen Partners 2012 (e-book)
  6. International Academy of Astronautics, Space Solar Power, The First International Assessment of Space Solar Power: Opportunities, Issues and Potential Pathways Forward, https://iaaweb.org/iaa/Studies/sg311_finalreport_solarpower.pdf Accessed 10.3.2020
  7. John Mankins, The Case for Space Solar Power, Virginia Edition Publishing; First Edition, January, 2014, Amazon Kindle Locations 422 and 879
  8. David R, Criswell, Solar Power via the Moon, The Industrial Physicist, April/May 2002, American Institute of Physics
  9. Solar Power Via The Moon, Lunar Solar Power Blogspot, https://lunarsolarpowersystem.blogspot.com/2010/03/solar-power-via-moon.html Accessed 24.4.2020
  10. Luna Ring, Solar Power Generation on the Moon, Shimizu Corporation https://www.shimz.co.jp/en/topics/dream/content02/ Accessed 10.3.2020
  11. Lunar Helium-3 as an Energy Source, The Artemis Project, http://www.asi.org/adb/02/09/he3-intro.html Accessed 10.3.2020
  12. Harrison H. Schmitt, Return to the Moon, Copernicus Books, Praxis Publishing Ltd. 2006
  13. John S. Lewis,Mining the Sky, Basic Books Basic Books, 1996, page 205
  14. John Mankins, The Case for Space Solar Power, Virginia Edition Publishing; First Edition, January, 2014, Amazon Kindle Location 7,129
  15. John Mankins, Ibid, Amazon Kindle Location 7,157
  16. Space Solar Power: Limitless clean energy from space, National Space Society
    https://space.nss.org/space-solar-power/ Accessed 14.07.2020
  17. Fabrizio Bozzato, Moon Power: China’s Lunar Helium 3 Vision, World Security Network, 2 June 2014, http://www.worldsecuritynetwork.com/China/fabrizio-bozzato-1/Moon-Power-Chinas-Lunar-Helium-3-Vision Accessed 10.3.2020
  18. International Academy of Astronautics, Space Solar Power, The First International Assessment of Space Solar Power: Opportunities, Issues and Potential Pathways Forward,
  19. World Energy Council, World Energy Scenarios: Composing Energy Futures to 2050,
    https://www.worldenergy.org/publications/entry/world-energy-scenarios-composing-energy-futures-to-2050
    Accessed 14.07.2020
  20. Arthur Woods, GEEO – Greater Earth Energy Organization. 10 December 2019,
    https://thespaceoption.com/geeo_the_greater_earth_energy_organization/
    Accessed 24.4.2020