A Whole New Energy Economy Could Emerge
Here's a recent news story about a new method for storing solar energy. Scientists have found a way to store it for up to 18 years.


So, imagine a story where people are trading solar energy cells, banks of cells, and using them to power civilization. Good-bye oil, natural gas, wind farms, etc. We don't yet know if this technology can be commoditized, but what would human civilization be like if we could pack a year's worth of household energy into a small container and take it with us?

Would that be enough to reverse the effects of global warming?

What would it do for space colonization?

As the art points out, additional work will be needed to scale the tech up to make it useful.

How did they figure out it will hold power for 18 years? I guess when the package arrived in China, they measured the remaining charge and calculated the rate of decay, which turned out to be quite low. They probably calculated that it would still have some agreed-upon useable level, say 80%, 18 years hence. You can barely keep unstabilized ethanol-laced gasoline on hand for half a year (ethanol-free can keep a little longer), and long-term storage of diesel fuel can be problematic too, esp. if it gets moist!

If they were at all accurate characterizing it as a "thermoelectric" device, that would mean that it is in effect a solid-state heat engine, and therefore requires not only a heat source, but also a heat sink, to work. In space, that shouldn't be a problem so long as the sink-side can be aimed away from the Sun and insulated from the heat-source side. (Are there any satellites powered by the thermoelectric effect?)

Does being based on thermoelectric principles mean the method can be used with other heat sources besides the Sun, such as waste heat from boilers and furnaces or from nuclear power plants or the like? That would seem to have potential uses. Auxiliary and instrumentation/control power for a boiler or furnace might be supplied in this way?
How fast would they charge and how many cycles of useable life (big issues with conventional rechargeable batteries, as anyone with a cell phone or laptop could attest!) would they have?

I could imagine that near-Sun orbiting banks of "batteries" based on this principle could be swapped in and out to power enterprises in the outer Solar system where solar arrays become impractical. This could be a use for Kerbal Cycler-type orbiting transports, ferrying these modules back and forth between near orbit charging locations and the outer Solar system. Land-based arrays could also find uses, though again in many high-power applications they'd have to be physically transported from sun-exposed charging station to end-use, and the discharged devices collected and brought back. They might become useful on Earth oceanic islands, for example, where conventional energy generation can be expensive and problematic. Perhaps they could be exposed to sun on big rafts, using the ocean as the heat sink. Likewise, there might be possibilities for powering colonies on rocky space bodies, and large satellites including the aforementioned cyclers.
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For I was talking aloud to myself...the old...choose the wisest person present to speak to...
Something I've always wondered about was if heat can be recaptured from work processes. So imagine you have an engine (for any task - not necessarily propulsion) in space that is radiating heat. Where does that heat go, except into the ship around it?

So why not recapture that heat for later reuse? I doubt we could build a perpetual energy system (the universe is supposedly that) but we could at least slow the process of losing heat from small closed systems.
The Carnot principle, which follows from the second law of thermodynamics, limits the amount of work a heat engine can produce, as a function of the ratio of the absolute temperatures of the heat source and the heat sink. Given that one can't obtain a heat sink at absolute zero, work can only be done when heat passes through a system; the second law forbids the "heat energy" (which scientists and engineers would call "enthalpy") in a material mass from being simply converted to work, which would destroy entropy. Therefore, a heat engine must allow a certain amount of heat to escape, in order to work at all.
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For I was talking aloud to myself...the old...choose the wisest person present to speak to...
The Carnot principle depends on the difference between the heat source and the environment it's in. And as it turns out, there are some recent experimental engines that recapture heat.

Here's a patent from 2007 describing such an auxiliary process (for automobiles).

Fluid heating system that uses recaptured waste heat energy of automobile engine

And this white paper from Caterpillar describes some industrial applications for harvesting heat from other processes:

More Than Heat and Power: A Fresh Look At Cogeneration

Waste heat cannot be universally harvested but we're learning to work with it in innovative ways. So in a spacecraft, I suspect that if the heat can be harvested before it escapes the craft, they can reuse it for other purposes.

After all, we've been doing this for decades with automobile heaters (and probably other vehicle heaters), which use excess heat provided by their engines rather than relying on separate engines to produce the heat.

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