Solar Power Satellites

The concept of Solar Power Satellites was invented in 1968 by Dr.Peter Glaser of Arthur D. Little Corporation.

They would be solar arrays in Geosynchronous orbit around Earth, beaming power to the ground via microwaves. The late Dr.Gerard K. O'Neill determined that these could most cheaply be built from lunar materials.

The receiving antenna (rectenna) is quite large, several square miles. The conversion efficiency of a rectenna is about 95%, compared to 20% or less for photovotaic cells. So SPS rectennas would require a lot less land area than conventional solar cells.

As for problems of radio interference: that has little to do with the size of the rectenna, but is certainly an issue which needs to be addressed in the system design. The problem of radio interference is solvable.

As for maintenance: very little maintenance is required for a rectenna system, it is essentially passive with no moving parts.

SPS will REDUCE heat pollution, not increase it.

Assuming the world is supplied by 200 SPS at 5 GW each. Each SPS loses 1 % into the atmosphere, a total of 10 GW of atmospheric heating caused by all the world's SPSes.

10 / 1.2 x 10E14 = 8 x 10e8 GW

So the entire losses of all the world's SPSes is 8 parts in a hundred million.

 This seems like a drop in the ocean to me, what do you think ? 

The present power stations of the world are injecting about thirty times as much into the atmosphere right now even as we type. A total of 2000 GW.

And even that is a drop in the bucket compared to global warming. According to the NASA GSFC website, the imbalance due to greenhouses gases as follows:

2.45 W/m2, the Earth is absorbing and not radiating to space.   Of this,  1.56 

W/m2 is due to CO2, 0.47 to methane and 0.14 to N2O.

This equates to an energy absorption rate of 12 million GW.

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SPS will reduce the problem of global warming, because it will replace the

12 million GW due to greenhouse gases, and the 2000 GW due to nuclear and 

fossil fuels, and replace it with a more tolerable 10 GW (worst case) of direct atmospheric absorption and 100 GW of waste heat at ground level.

Deceptively cheap (subsidized) energy can continue to be readily available using nuclear power and fossil fuels for a couple of centuries at least. Solar power Satellites (SPS) will not compete head to head on price alone in the foreseeable future.

On the other hand....

The collateral damage caused by fossil fuels and nuclear fuels far outweighs their deceptively low price. The real price for these fuels is very high when you consider these factors:

Fossil fuels:

- military cost of securing sources of supply and supply channels, 

with associated geopolitical problems and trouble with the local insurgents

- huge balance of trade deficits from importing them 
- cost of the war on terror (terrorists funded by oil revenues) 
- global warming exacerbated by greenhouse gases 
- air pollution - reduced life expectancy / healthcare costs 
- water pollution (e.g. Mercury from coal) - reduced life expectancy / healthcare costs 

Nuclear fuels:

- military cost of securing supply chains against theft 
- military cost of securing waste sites against theft 
- cleanup cost of decommissioning power stations 
- cost of meltdown - reduced life expectancy / healthcare costs 
- cost of waste leakage - reduced life expectancy / healthcare costs 
- social cost of draconian global security regimes (big brother) 

If society ever reaches the conclusion that fossil fuels and nuclear fuels are undesirable for the above reasons, then there is no remaining alternative to SPS for clean inexhaustible power on a global scale.

But as long as society is willing to continue subsidizing fossil fuels and nuclear systems, then SPS is not an option.