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Fusion reactors: Not what they’re cracked up to be

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Re: Fusion reactors: Not what they’re cracked up to be

#41

Post by Robotbeat »

short_sells_poo wrote: post #40
Robotbeat wrote: post #26

There's nothing quite like trying to get fusion to work for a while to make you appreciate how awesome fission technology is. If we applied even half the cleverness needed for fusion to making better fission technology, we'd probably be way better off. ...and then there's solar. Why even bother with producing the energy, just capture it with a very thin solid state device! Just need to automate the planting of solar…

How exactly do you propose to get that electricity from the desert to say Finland? Furthermore, you need to plaster a vast area in the desert with solar plants, which brings along all sorts of concentrated security risks. The alternative is to have many smaller plants dispersed, which results in a big loss of efficiency. I'm all for clean energy, but you seem to be handwaving away pretty huge issues as "thought exerc…

High latitudes (above 50 degrees) have a big problem with solar power. Luckily, almost the only people who live that far from the equator are Northern Europeans, who tend to have access to hydro and nuclear. (this is why it's so stupid for Germany to shut down their nuclear power... they're replacing it with coal, brown coal, and gas!)

The vast, VAST majority of the world's population lives FAR closer to the equator.

Again, you seem to have ignored the part of my post where I mentioned installing enough solar to produce power even during cloudy days. Cost of utility solar is super cheap now. If it continues reducing in cost, it'll be plenty cheap enough to just install 3-5x as many panels as you need to provide power during cloudy days. Yes, solar CAN get cheap enough for that to be a good idea.

Re: Fusion reactors: Not what they’re cracked up to be

#42

Post by Robotbeat »

Recurecur wrote: post #36
mrfusion wrote: post #34

Earlier quoted context omitted.

Not just deserts. You could also float them in the ocean, no? We have 70% of our planet we're not using. Spread them far enough apart and add some movement and shadows wouldn't hurt wildlife much.

The ocean environment isn't easy on equipment, plus storms are a major issue. Then there's cabling...

That all looks trivial compared to the challenges of fusion power, though.

Re: Fusion reactors: Not what they’re cracked up to be

#43

Post by Robotbeat »

DigitalJack wrote: post #39
Robotbeat wrote: post #26

There's nothing quite like trying to get fusion to work for a while to make you appreciate how awesome fission technology is. If we applied even half the cleverness needed for fusion to making better fission technology, we'd probably be way better off. ...and then there's solar. Why even bother with producing the energy, just capture it with a very thin solid state device! Just need to automate the planting of solar…

I have to think there are major ecological concerns with blocking sunlight over large areas. They may not be negative impacts, but surely it isn't a no-impact situation.

There is always some impact.

There's a disease in our energy discussions where if something has ANY effect or can be measured at all, it is considered a big no-no. We lack a sense of proportion. Radiation is SUPER easy to measure even tiny amounts, for instance, since you can look for the signature of a certain decay tree, so people hear that you can measure radiation from Fukushima and lose their minds. Likewise, people make a big deal about solar using up a lot of land, but then forget that agriculture uses up on the order of 100 TIMES the land that solar would take up if we relied entirely on solar for electricity. The sense of scale is entirely lacking.

Re: Fusion reactors: Not what they’re cracked up to be

#44

Post by DennisP »

Robotbeat wrote: post #35

(Thinking about the far future, here.) Inertial fusion using Deuterum and Helium 3 would solve a lot of these problems. Of course, He3 is rare here on Earth. I don't think mining the Moon for He3 makes much sense. It's just too rare in the lunar soil. Instead, my favorite concept is mining it from Uranus (whose gravity at Earth-like pressures is actually slightly less than 1g...). There's vast amounts available at us…

Another option is to simply breed He3 with pure deuterium fusion; the output of the D-D reaction is He3 half the time, and otherwise tritium, which decays into He3 with a 12-year half-life. D-D produces neutrons but at normal fission energies, not the really high energy of D-T neutrons.

Fusion startup Helion, which is funded by YCombinator, is attempting a hybrid D-D/D-He3 reactor, saying the combined reaction would produce only 6% of its energy in the form of neutron radiation.

Re: Fusion reactors: Not what they’re cracked up to be

#45

Post by leephillips »

Spare_account wrote: post #38
SomeStupidPoint wrote: post #17

Earlier quoted context omitted.

Are you guys talking about different things? One seems to be talking about energy released by while the other is talking about energy captured from. I think GP was criticizing the news for making it sound like the first hasn't happened when only the second hasn't happened. (At least, in my understanding.)

The BBC article linked above describes a very specific scenario which matches neither of your described options. " The amount of energy released through the fusion reaction exceeded the amount of energy being absorbed by the fuel " This doesn't describe the relationship between the amount of energy injected by the lasers and the energy emitted by the fusion reaction. Presumably a lot of the energy injected by the las…

'This is a step short of the lab's stated goal of "ignition", where nuclear fusion generates as much energy as the lasers supply.'

Which is just what I was pointing out. And it's a large step from honest break-even, where you count the energy input into the laser system (it's not 100% efficient). And a huge step from practical break-even, where you count the energy required to run the plant.

Re: Fusion reactors: Not what they’re cracked up to be

#46

Post by short_sells_poo »

Robotbeat wrote: post #41
short_sells_poo wrote: post #40

Earlier quoted context omitted.

How exactly do you propose to get that electricity from the desert to say Finland? Furthermore, you need to plaster a vast area in the desert with solar plants, which brings along all sorts of concentrated security risks. The alternative is to have many smaller plants dispersed, which results in a big loss of efficiency. I'm all for clean energy, but you seem to be handwaving away pretty huge issues as "thought exerc…

High latitudes (above 50 degrees) have a big problem with solar power. Luckily, almost the only people who live that far from the equator are Northern Europeans, who tend to have access to hydro and nuclear. (this is why it's so stupid for Germany to shut down their nuclear power... they're replacing it with coal, brown coal, and gas!) The vast, VAST majority of the world's population lives FAR closer to the equator.…

I haven't ignored the part where you mentioned overprovisioning. Where do you propose to put the excess power during sunny days? Stable baseline sources like nuclear cannot just be shut down or spun up on a moment's notice to accomodate a vast number of solar energy entering or leaving the grid. At the same time, we don't have a capability to store electricity at sufficient scale so we do need the stable baseline to cover a high enough percentage of our production.

The fact of the matter is, as long as we don't have a scalable storage solution, power sources where we can't regulate the power output cannot take up base load and can at best be a small overlay that can pick up load if the beneficial weather happens to coincide with higher load requirements.

Re: Fusion reactors: Not what they’re cracked up to be

#47

Post by fao_ »

short_sells_poo wrote: post #40
Robotbeat wrote: post #26

There's nothing quite like trying to get fusion to work for a while to make you appreciate how awesome fission technology is. If we applied even half the cleverness needed for fusion to making better fission technology, we'd probably be way better off. ...and then there's solar. Why even bother with producing the energy, just capture it with a very thin solid state device! Just need to automate the planting of solar…

How exactly do you propose to get that electricity from the desert to say Finland? Furthermore, you need to plaster a vast area in the desert with solar plants, which brings along all sorts of concentrated security risks. The alternative is to have many smaller plants dispersed, which results in a big loss of efficiency. I'm all for clean energy, but you seem to be handwaving away pretty huge issues as "thought exerc…

> Furthermore, you need to plaster a vast area in the desert with solar plants, which brings along all sorts of concentrated security risks.

I mean, most of the same security risks appear in oil pipelines and extraction.

Re: Fusion reactors: Not what they’re cracked up to be

#49

Post by Robotbeat »

fao_ wrote: post #47
short_sells_poo wrote: post #40

Earlier quoted context omitted.

How exactly do you propose to get that electricity from the desert to say Finland? Furthermore, you need to plaster a vast area in the desert with solar plants, which brings along all sorts of concentrated security risks. The alternative is to have many smaller plants dispersed, which results in a big loss of efficiency. I'm all for clean energy, but you seem to be handwaving away pretty huge issues as "thought exerc…

> Furthermore, you need to plaster a vast area in the desert with solar plants, which brings along all sorts of concentrated security risks. I mean, most of the same security risks appear in oil pipelines and extraction.

And the vast area is still very small compared to agriculture. And it can be done in chunks. The electrical grid is concentrated by its very nature, but we still manage just fine.

(Solar is also one of the few truly distributed power sources, but I expect most power in the future will come from vast solar farms due to the ease of automation.)

Re: Fusion reactors: Not what they’re cracked up to be

#50

Post by short_sells_poo »

fao_ wrote: post #47
short_sells_poo wrote: post #40

Earlier quoted context omitted.

How exactly do you propose to get that electricity from the desert to say Finland? Furthermore, you need to plaster a vast area in the desert with solar plants, which brings along all sorts of concentrated security risks. The alternative is to have many smaller plants dispersed, which results in a big loss of efficiency. I'm all for clean energy, but you seem to be handwaving away pretty huge issues as "thought exerc…

> Furthermore, you need to plaster a vast area in the desert with solar plants, which brings along all sorts of concentrated security risks. I mean, most of the same security risks appear in oil pipelines and extraction.

True, and this is a issue today as well. Which is why I think that proposing a solution that compounds this issue even further should not be taken lightly.

Edit: put differently, why should we adopt a new solution that is even more exposed to the already known risks?

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