Comment by nkrisc
4 days ago
The issue with that is how to direct the energy back to Earth, and then collect it. If you can’t direct it and it radiates in all directions then only a tiny fraction of the produced photons will reach Earth. Then you need to collect those photons in order to do useful work, otherwise they will just heat the earth. If the distance needed to remain safe is greater or less than geosynchronous orbit, you’ll need collectors all over the Earth as they won’t have constant line of sight towards the source and experience a “nighttime” of sorts. There is also the issue of atmospheric effects, such as high densities of moisture, absorbing or scattering the photons, reducing the efficiency of the collectors. So it could work, but the effective maximum capacity will always be quite limited and the overall process highly inefficient relative to the total fusion energy produced.
Actually you don't want the transmission process to be 100% efficient. If you really captured all the fusion energy transmitted (or even just the small part of it reaching Earth), all sorts of people would complain, trust me! But fortunately that fusion reactor has more than enough power to go around...
If only it were smaller and closer. We could make it smaller by using a force other than gravity to compress the matter. Perhaps a very strong magnetic field? If it was strong enough you’d only need a fraction of the matter.
OTOH, the concept proposed by OP is already implemented and has been working reliably for billions of years with trillions of successful deployments, while this newfangled technology you are proposing still has to be demonstrated to work...
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> But fortunately that fusion reactor has more than enough power to go around...
"All the energy we could ever use, forever and forever and forever."
"Not forever,"
Insufficient data for a meaningful answer.
They wouldn't complain for long though
How about we use solar panels to collect that energy? And then we add batteries to fix holes in supply when the panels can’t see the power source.
That sounds great, but those batteries are both too expensive right now and not available. People choose the cheaper alternative which are to use thermal energy where they burn gaseous hydrocarbons when the panels can’t see the power source. When the time and price is right we may stop building new such thermal power sources, but for now we can define them as the current best choice and even call them green since everyone has the intention to replace them in the future some day.
> That sounds great, but those batteries are both too expensive right now and not available.
In December, Chinese battery pack prices declined to 100 $/kWh according to BNEF, which was a new record low. Also battery production goes up by at least 20% per year for the last years and battery energy storage installations go up by 30%, see BYD, CATL, and Tesla annual reports.
Availability might be a problem in the West, but China is installing them on a massive scale. So being “not available” (if that’s the case) should, I think, be interpreted as a Western call to action and not as a fact of life. South Korea produces 30% of all car batteries and multiple South Korean plants are planned for the US, so I have hope that things will start moving.
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I think you are on to something here
> The issue with that is how to direct the energy back to Earth, and then collect it.
‘Simpler’: move earth to where the energy goes: https://en.wikipedia.org/wiki/Dyson_sphere
Maybe we can use the excess photons in another way? We could bio-engineer sunlight collection devices that would take in sunlight and use it to break apart CO2 and produce other useful materials. We could then spread them around the planet to use the excess photons in a productive way. We gain valuable complex molecules and break down CO2 so a win win!
Hm, it could be possible to engineer devices that use the excess photons reaching Earth along with environmental CO2 and H2O to assemble sugars and other carbohydrates. Depending on the specific reactions, we could even end up with O2 as a by-product, which would be additionally useful for us.
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