I’ve stumbled across a number of articles recently that seriously propose that we set up huge solar arrays in space and wirelessly beam kilowatts back to earth such as this one highlighting the plans being discussed in Japan. The originators these plans are very legitimate and there is even an international conference being held right now on the subject in Ontario. The subject has its own advocacy blog. Then there is the National Space Society version. NASA is working on it. MIT is working on it:
Space solar power stations are envisioned as large solar power collectors in geosynchronous earth orbit. Solar energy would be gathered by photovoltaic cells and converted to microwaves so that it can be beamed wirelessly to receivers on earth. Space solar power is clean, inexhaustible, available 24 hours a day, and has the potential to generate as much energy as terrestrial power plants.
If the orbit is geosynchronous though, wouldn’t it be in the shadow of the earth for at least 8 hours per day? I suppose that the further away from the earth it is placed in orbit, the longer the sunlight would strike its surfaces, but it also seems that the limiting technological factor of the beaming of microwaves from the satellite to the surface of the earth would also require that the orbit be as low as possible.
The idea is tempting since the available energy outside of the atmosphere is 136% that available on the surface due to the reflective effect of the atmosphere itself. The surface are required to fuel the world with solar would therefore be 74% of that required on a land-based installation.
And what about the arrows in this diagram that are bouncing back into space? Don’t we want that to continue to be the case? All things equal, wouldn’t it be adding to the overall amount of heat energy on the planet to harness more Joules of solar radiation than would naturally be absorbed by dark soils and plants down below? The law of conservation of energy tells me that bringing more sun energy into the atmosphere than would naturally be absorbed is not necessarily a good idea. Sure the energy is immediately captured as electricity and then sent to run kinetic devices, but the running of those devices creates heat and that heat is then a part of our inner atmosphere. Multiplying this continuously over many years and the effect may add up.
I don’t claim to know the answer to this, but I’m a bit of a precautionary person when it comes to messing with the natural order of things. Maybe it is better to stay down on the beautiful surface of the planet where we naturally are comfortable and to figure out solutions to our problems that are based on earth rather than out in space.