A typical thought processSubmitted by Kaarssteun t3_yw3smv in singularity
purple_hamster66 t1_iwhgnge wrote
Reply to comment by tiberius-Erasmus in A typical thought process by Kaarssteun
Read about The Underpants Gnomes.
You’re missing a key feature of fusion energy… we don’t know how to do it and it’s likely we’ll never figure it out. Instead of a $1T device, why not just add $1T of solar panels and leverage the fusion in the sun that we already have?
Without massive amounts of new energy, we can’t produce enough clean water, food, heat/cool air, and carbon-free transport for the people we already have.
[deleted] t1_iwhz0y0 wrote
> You’re missing a key feature of fusion energy… we don’t know how to do it and it’s likely we’ll never figure it out.
That's an odd claim.
darthdiablo t1_iwi2r8l wrote
Yeah - unless I'm mistaken, I thought it was more like we know how fusion works, the problem is it's a matter of figuring (engineering) how we can make fusion happen on a smaller (non-stellar-scale) level?
Nieshtze t1_iwihufm wrote
It is easy to perform fusion in a non-stellar scale. They did that in the 50s with hydrogen bombs.
The challenge is controlling the reaction.
[deleted] t1_iwij5em wrote
[deleted]
-ZeroRelevance- t1_iwimwko wrote
Hydrogen bombs are a mix of fission and fusion. They create an explosion like a standard atomic bomb using fission, which superheats the hydrogen in the bomb to initiate a fusion reaction, which increases the energy output manyfold.
purple_hamster66 t1_iwzijto wrote
Controlled fusion, for the purposes of energy production, is not a solved problem. Yes, we can maintain the conditions for about a picosecond. That’s what I mean by we don’t know how to do it.
When I say it’s unlikely we’ll ever figure it out, well, that’s because the new experimental designs using plasma and huge powerful magnets are proceeding, but a single fault or destabilization in the mag fields holding the 100Mº hydrogen and the entire place will explode. Adding 100Mº to the atmosphere is a big issue, and one that’s not likely to help with global warming. The risks are too big to continue this experiment, politically. Nuclear bombs mostly destroy due to the pressure waves they create, and this explosion would rival a bomb’s destructive power... it could kill an entire city. If it ignites the atmosphere, the only thing that would save us is the low pressure of atmospheric hydrogen, which means it could exhaust it’s fuel supply eventually.
SoylentRox t1_iwhhk1l wrote
Agree totally on the solar. The only thing the fusion does for you is it saves you having to develop a long term method of energy storage. There are lots of ways to do this but there are tradeoffs.
Flow batteries being the most promising because they are efficient - you get 80 percent plus of the stored energy back - so you just need some electrolyte chemistry that is not too toxic and cheap and can be stored in gigantic cheap unpressurized tanks.
You can also make hydrogen, maybe store it in metal or as ammonia or just pressurized gas, and burn it in fuel cells. This loses a lot of energy and is also expensive equipment.
There are also various pressurized air and heat storage concepts - they all have cheap storage material but poor efficiency.
Note that hydroelectric and lithium battery storage is not long term, it's short term storage. It's for the next couple days. You need something to store energy to make up for seasonal shortfalls and for black swan periods of little renewable production for a while
purple_hamster66 t1_iwzjdiz wrote
I think the coolest hybrid energy storage solution is melting salt stored in tracker trailers and trucking it to the destination substation where it generates electricity as it cools. This can allow us to truck energy to places that didn’t get enough renewable energy (black swan event), or to emergency sites (earthquake takes out a power plant; floods; tsunami), or as long-term energy storage. The trucks can use the energy they are transporting to power the transport, too, so fossil fuels are not needed either.
SoylentRox t1_iwznvv0 wrote
Maybe? Why salt. Why not just heat up a bunch of ceramic bricks to almost their melting point. Salt especially hot salt can corrode and melt things. With the bricks, if the truck crashes, you just end up with glowing pottery on the ground. Don't touch it but it won't flow to you.
You also have poor efficiency converting from the heat back to work, you need a steam engine.
Frankly probably better to just transport diesel.
purple_hamster66 t1_ix0847c wrote
Salt is used in thermal energy storage systems because of it’s enormous capacity to hold heat. I don’t know how ceramic compares, but the latent heat involved in the state change (from solid to liquid) is important because it extends the heat that can be trapped. As I understand it, it’s not pure salt, but may also have thermal oil and high-pressure water & pumps. Depends on the usage.
I don’t think they’ve thought about crashes because none of these systems are currently mobile. Even though I would imagine that molten salt flows quite slowly, the amount of energy in it would melt/damage most things. But when it finally cools, though, it’s just salt, so cleanup is easy.
Some systems use a Rankine Cycle steam turbine, like you said. Others have been designed to use thermocouples, devices that convert nearly 100% of heat differences (over a threshold) to electricity and vice versa. It’s a form of heat pump, like those used in houses, but this thermocouple is designed for much higher heat differences. Since it’s trivially reversible, the same device is used for both directions.
One other cool hybrid is heating the salt using mirrors in a vast field, then generating the electricity from the steam engine. This means you can store the energy until later if you have more mirrors than your current grid needs.
puzzleheadedmaroon-5 t1_iwnizw1 wrote
$1 trillion of solar panels wouldn't make a dent in the world's energy needs. How about $1 quadrillion? And where would you get the minerals to make them? Dig them out of the ground using fossil fuels?
We do know how to do nuclear fission. Fusion isn't necessary.
purple_hamster66 t1_iwradue wrote
True, we’d need more solar than $1T, but solar does NOT have to include minerals at all. For decades, homes have been producing hot water via rooftop pipes, and heating homes but capturing passive sunlight on stone facades and floors. There are also solar paints that include no minerals but are painted on rooftops… these are not high efficiency but are really really cheap.
puzzleheadedmaroon-5 t1_ixslb7c wrote
>rooftop pipes.... stone facades and floors....solar paints
Those are all made of minerals, except possibly rooftop pipes, which can be made out of plastic.
"Mineral: a solid inorganic substance of natural occurrence." - OED
purple_hamster66 t1_iy028dy wrote
People are mostly concerned about mining when it comes to REMs (Rare Earth Minerals), not just minerals in general. Many commonplace minerals are not mined but found near the surface or in water. And it’s not just the destructive polluting nature of the mines but also the danger to miners. (For more expensive minerals, I’m guessing the danger will be minimized by using robot miners within a decade).
IMHO, the amount of REMs in solar panels is tiny compared to the amounts used for electronics, power systems, and manufacturing in general. This could be checked.
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