Lance wrote:Мастер wrote:We're currently having some issues with the rapid release of large amounts of solar energy that accumulated as storage in chemical form. If you had a lot of new energy to the planet, that it's not currently receiving, one would need to figure out how to get rid of some of it when the work is done, no? Maybe turn hydrocarbon combustion products back into oil. I can't help but wonder whether dealing with the output of energy consumption is going to be a far more difficult problem than finding new sources of energy.
I'm not sure I completely follow you here. If we use the energy directly, or by converting to, say, electricity, what are the byproducts? We're not releasing from a stored state, we're just consuming it.
Ultimately, it ends up as heat. If we use it to drive cars, there is the internal friction of the engine (and other parts), which produces heat, the friction of the brakes, of the tyres with the road, and air friction. All of these produce heat. When we drive a car up the hill, the energy is stored as potential energy, not heat, but when we drive back down the hill, it's back out. As far as I know, there is no theoretical limit to how efficient we could make cars, but if we succeed in making ultra-efficient cars, then the need for energy goes away along with the waste heat.
If we heat homes, that's direct production of heat, which eventually leaks out through the doors, windows, walls, etc. Air conditioners produce heat. When we use energy to take some molecules and turn them into other molecules (so sometimes when we manufacture stuff), that can absorb energy. But unless we keep stockpiling more and more of these goods, without ever throwing them away, they'll eventually revert to their original form (or some other form), releasing the energy. Sources that were going to turn into heat anyway (solar, hydroelectric, wind?) seem like they wouldn't add to the heat, but I'm guessing that by the time you're building energy-capturing structures in space, you've probably already tapped these sources about as well as you can.
When I think about it, I did misspeak a bit - when we burn fossil fuels, the problem is not so much the direct release of the energy, but production of gasses that reduce the planet's radiation of heat. But I'm not sure that that really changes anything. If the additional energy obtained from one of these spheres is a very small fraction of what already hits the earth, then building a space structure is probably not the optimal way to get the additional power. If it's a lot, and you beam it back to earth (if it's consumed in space, that's a different story), then that's a large amount of additional incoming energy, that's eventually going to turn into heat. It must be got rid of somehow, as the default is that the earth heats up and radiates away, isn't it?
Lance wrote:Мастер wrote:There's lot's of energy lying around on earth - much of it is more expensive to tap than current sources, which makes sense (one would normally access the cheapest sources first). At least at current levels of technology, there's lots of energy on earth that we're not using now, that's going to be cheaper than building a solar collector in space. Technology for building space structures may improve, but then again, so might technologies for extracting energy from earth-bound sources. But either way (bring in lots of new energy, or tap currently untapped sources), it's going to get a bit hot if we don't figure out some way to get rid of it.
But sources are not unlimited.
True enough, but demand is also not unlimited. The earth will exist for a finite amount of time. But, projecting the world's energy needs for a few hundred million or billion years, I suspect, will necessarily involve some uncertainty.
Lance wrote:As time passes and resources are depleted, production costs go up. You have to keep tapping more and more expensive sources.
That is already happening (alright, we're on a several year holiday from rising energy prices, but I suspect that's not permanent). That's why civilisation collapsed, as per rational analysis conducted at astronomy boards.
Lance wrote:At some point, it may become cost-effective to take on even such a large project.
It might, although we're quite far from that point.
Lance wrote:It might even become a choice a civilization has to make or risk perishing.
If by "perish", we mean cease to exist, I think that's going too far. They can downsize their energy consumption to what comes off if the local star. But if they were living at a level of energy consumption far beyond this level, then downsizing might turn their civilisation into something unrecognisable.
Lance wrote:Of course, there could be more to it than just energy. We now know that energy can be converted to matter. With significant advancement, it may become easy and commonplace. This would answer how such a civilization could gather the materials to construct such a mega structure in the first place.
That would be the reverse of nuclear power
. But isn't the exchange rate really bad? That is, huge amounts of energy make only tiny amounts of matter? If so, and your problem is you don't have enough energy, this might make the problem worse rather than better.
Has someone managed to do this in lab conditions?
Lance wrote:Мастер wrote:Of course, this thread is about some potential energy-capturing structure around a different star, so conditions on earth might be a bit different.
Isn't speculating about this kind of stuff fun?
Not on days when I'm typing on a tablet device