Preface. This 2020 article “Solar Power Beamed Down To Earth From Space Moves Forward” will leave you all warm, fuzzy, and unworried about the future. The Scientists Will Come Up With Something. 

But that’s because you know little to nothing about orbital solar power.  It’s hard to be a bullshit detector without knowing something a topic, but you can still notice missing information.  How much will all this stuff weigh?  How much will it cost to launch into space?  How often will maintenance flights need to be made? And if the Air Force and Northrup Grumman are building this solar contraption, it might occur to you that this is more likely to be a weapon than an orbital solar power solution.

A genuine orbiting solar power generator meant to provide electricity could turn into a weapon if the computer hiccuped and allowed the down link beam to drift off target by a few degrees, slewing the beam across the countryside and barbecuing whatever was in its path with a few gigawatts of microwave radiation.  

Alice Friedemann   www.energyskeptic.com  author of  “Life After Fossil Fuels: A Reality Check on Alternative Energy”, 2021, Springer; “When Trucks Stop Running: Energy and the Future of Transportation”, 2015, Springer; Barriers to Making Algal Biofuels, and “Crunch! Whole Grain Artisan Chips and Crackers”. Podcasts: Collapse Chronicles, Derrick Jensen, Practical Prepping, KunstlerCast 253, KunstlerCast278, Peak Prosperity , XX2 report

***

In theory, orbiting solar arrays could make electricity, convert it to microwaves and then beam that energy to a ground antenna where it would be converted back to electricity. But to make 10 trillion watts of power would require about 660 space solar power arrays, each about the size of Manhattan, in orbit about 22,000 miles above the Earth (Hoffert et al 2002).

So how are you going to get these gigantic solar power satellites into space?  Normile (2001)  estimates that it would take 1,000 space shuttle payloads to deliver the necessary material, an order of magnitude more than the number of missions needed to construct the international space station.  The average space shuttle mission cost $450 million (NASA 2020). Without breakthroughs in launching technology, space solar power “would be impractical and uneconomical for the generation of terrestrial base load power due to the high cost and mass of the components and construction.”

Nor can we be sure that there will be breakthrough advances in a number of technologies according to Richard Schwartz, an electrical engineer and dean of engineering at Purdue University in West Lafayette, Indiana (NRC 2001).

And we can’t run wires from Earth’s surface to an orbiting satellite, so the solar energy would have to be converted into electric energy on obard to power a microwave transmitter or laser emitter, and focus its beam toward a collector on Earth.  

And can you imagine how often astronauts would have to go into space to fix and maintain hundreds of these objects, how much fossil energy that would take at a time when fossil energy is declining?

And astronauts will have to up there to replace the solar panels, because space is hostile and the solar panels will suffer about eight times as much damage and degradation as they do on earth.

These truly gigantic orbital arrays could be hit by space junk and create even more space junk, taking out other satellites or orbital solar stations and their microwave emissions would probably interfere with the functioning of other satellites.

Meanwhile, shell out even more money for the enormous receiving stations on the ground.

Power beaming from geostationary orbit by microwaves  requires very large ‘optical aperture’ sizes, including a 1-km diameter transmitting antenna in outer space, and a 10 km diameter receiving rectenna on earth, for a microwave beam at 2.45 GHz. These sizes can be somewhat decreased by using shorter wavelengths, although they have increased atmospheric absorption and even potential beam blockage by rain or water droplets. Because of the thinned array curse, it is not possible to make a narrower beam by combining the beams of several smaller satellites. The large size of the transmitting and receiving antennas means that the minimum practical power level for an SPS will necessarily be high; small SPS systems will be possible, but uneconomic (Wiki 2020).

To give an idea of the scale of the problem, assuming a solar panel mass of 20 kg per kilowatt (without considering the mass of the supporting structure, antenna, or any significant mass reduction of any focusing mirrors) a 4 GW power station would weigh about 80,000 metric tons, all of which would, in current circumstances, be launched from the Earth. Very lightweight designs could likely achieve 1 kg/kW, meaning 4,000 metric tons for the solar panels for the same 4 GW capacity station. This would be the equivalent of between 40 and 150 heavy-lift launch vehicle (HLLV) launches to send the material to low earth orbit, where it would likely be converted into subassembly solar arrays, which then could use high-efficiency ion-engine style rockets to (slowly) reach GEO (Geostationary orbit).

The cost to build orbital solar is, well, out of this world.

With an estimated serial launch cost for shuttle-based HLLVs of $500 million to $800 million, and launch costs for alternative HLLVs at $78 million, total launch costs would range between $11 billion (low cost HLLV, low weight panels) and $320 billion (‘expensive’ HLLV, heavier panels).To these costs must be added the environmental impact of heavy space launch emissions, if such costs are to be used in comparison to earth-based energy production. For comparison, the direct cost of a new coal or nuclear power plant ranges from $3 billion to $6 billion per GW (not including the full cost to the environment from CO2 emissions or storage of spent nuclear fuel, respectively); another example is the Apollo missions to the Moon cost a grand total of $24 billion (1970s’ dollars), taking inflation into account, would cost $140 billion today, more expensive than the construction of the International Space Station.

SBSP costs might be reduced if a means of putting the materials into orbit were developed that did not rely on rockets. Some possible technologies include ground launch systems such as Star Tram, mass drivers or launch loops, which would launch using electrical power, or the geosynchronous orbit space elevator. However, these require technology that is yet to be developed. Project Orion (nuclear propulsion) is a low cost launch option which could be implemented without major technological advances, but would result in the release of Nuclear fallout.

Patterson (2003) wrote “It’s hard to calculate the cost per pound of deliver to the geosynchronous orbit (GSO), but Futron Corporation is paid by the companies that actually launch satellites to make estimates (www.futron.com). In 2003, Futron estimated GSO launch vehicles cost per pound at $17,000 (Western) and $7,000 (non-Western). In 2000, the costs were around $12,000 per pound. Low Earth Orbit, (LEO) is much cheaper. At $7,000 per pound, it would cost $42 billion to launch a 3,055-ton satellite into geosynchronous orbit, and another $4.2 billion for every refueling run. These costs are for UNMANNED objects.”

References

Hoffert MI, Caldeira K, Benford G, et al (2002) Advanced Technology Paths to Global Climate Stability: Energy for a Greenhouse Planet. Science 298: 981-987.

NASA (2017) Space Shuttle and International Space Station. National Aeronautics and Space Administration.

Normile D (2001) SPACE SOLAR POWER. Japan Looks for Bright Answers to Energy Needs. Science 294: 1273

NRC (2001) Laying the Foundation for Space Solar Power: An Assessment of NASA’s Space Solar Power Investment Strategy. Washington, DC:
The National Academies Press. https://doi.org/10.17226/10202.

Patterson R (14 Jan 2003) Energyresources message 28631

Wiki (2020) Space-based solar power. https://en.wikipedia.org/wiki/Space-based_solar_power