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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

#211

Post by opo »

Retric wrote: post #194
opo wrote: post #191

Earlier quoted context omitted.

>100,000 tons of methane with a half life of less than 10 years. The math is complex and 1 ton of methane becomes more than one ton of CO2, You are downplaying the impact of methane. As I quoted in the last post, the IPCC estimate is that over 100 years a given amount of methane is 34 times more potent as a heat-trapping gas compared to CO2. Over a 20 year period (which is probably more relevant considering where we…

That's just lying with numbers. 86 / 5 = 17.5 so average from year 20 to year 100 is 34 - 17.5 = 16.5x. And again the majority of that 16.5 is over years 20-40. Further, because of this decay increases in release rate don't stack at 86x year over year. You get a magnified increase in the first year and a smaller net increase every year after that until your down to the carbon content of methane. Under 10% total gen f…

>That's just lying with numbers.

No, those numbers are from the IPCC which represents the mainstream consensus. Take it up with them if you think you are right and they are wrong. Using the 20 years number is reasonable considering how far along we are in climate change. As the IPCC report states: "There is no scientific argument for selecting 100 years compared with other choices (Fuglestvedt et al., 2003; Shine, 2009). The choice of time horizon is a value judgement since it depends on the relative weight assigned to effects at different times."

>...Under 10% total gen from peaking power is viable with over production of wind and solar and zero grid storage.

Yea I hear advocates make such claims all the time. Unfortunately I never hear the same thing from people who actually run a major utility. We might get there someday, but for now I have to agree with Gates: "...What they mean is that at noon in Arizona, the cost of that kilowatt-hour is the same as a hydrocarbon kilowatt-hour. But it doesn’t come at night, it doesn’t come after the sun hasn’t shone, so the fact that in that one moment you reach parity, so what? The reading public, when they see things like that, they underestimate how hard this thing is. So false solutions like divestment or “Oh, it’s easy to do” hurt our ability to fix the problems. Distinguishing a real solution from a false solution is actually very complicated."

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

#212

Post by thatcat »

mseebach wrote: post #89
antisthenes wrote: post #75

Earlier quoted context omitted.

I'm surprised to see this kind of simplistic reductionist thinking on HN. "Just cut the cables" isn't trivial. Have you ever seen a high voltage tower? Not only are they not accessible without professional gear, it's also going to require even more expensive gear to cut multiple inch thick conductors. In all likelihood he power to Europe will be transmitted via multiple undersea cables, the effort of disrupting which…

> the effort of disrupting which would be unavailable to all but state agents It's a good thing then that there is a long history of all state agents in northern Africa maintaining friendly and stable relations with European governments. (Yes, said Europeans also carry a great deal of responsibility for this situation, but that doesn't make the situation any more tractable).

Wouldn't creating a partnership then help to stabilize that relationship?

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

#213

Post by [deleted] »

jandrese wrote: post #106
erikgrinaker wrote: post #23

Much of the (valid) criticism in this article relates to the deuterium-tritium fuel cycle. This is the easiest reaction to accomplish on Earth, so most experimental reactors are designed with this fuel in mind, and we're certainly having a hard enough time making even this work. However, I've always considered D-T fusion an intermediate step on the path to aneutronic fusion, such as Helium-3 or proton-Boron reactions…

Billion Kelvin operating temperatures make me super skeptical about the practicality of that solution in my lifetime. It's just so many orders of magnitude beyond where our materials science is.

[deleted]

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

#214

Post by petre »

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…

Solar PV is great distributed power source to install on roofs and maybe that's it. You can combine it with partial storage for household consumption, but even that is a burden.

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

#215

Post by petre »

antisthenes wrote: post #75
short_sells_poo wrote: post #63

Earlier quoted context omitted.

Sorry I worded that sentence poorly. Let's assume two scenarios: a) We create a 200 square mile solar field in the Sahara, from which cables run to Europe to supply electricity. To take this plant out, one just cuts the cables. There, you just plunged Europe into darkness. b) We create a 20x 10 square mile solar fields in the Sahara, all dispersed over a very large area. Well, this is an engineering and construction…

I'm surprised to see this kind of simplistic reductionist thinking on HN. "Just cut the cables" isn't trivial. Have you ever seen a high voltage tower? Not only are they not accessible without professional gear, it's also going to require even more expensive gear to cut multiple inch thick conductors. In all likelihood he power to Europe will be transmitted via multiple undersea cables, the effort of disrupting which…

It has been done in Crimeea last year. Pro gear to cut HV cables = C4. How do you run an undersea cable through the desert?

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

#216

Post by petre »

thatcat wrote: post #212
mseebach wrote: post #89

Earlier quoted context omitted.

> the effort of disrupting which would be unavailable to all but state agents It's a good thing then that there is a long history of all state agents in northern Africa maintaining friendly and stable relations with European governments. (Yes, said Europeans also carry a great deal of responsibility for this situation, but that doesn't make the situation any more tractable).

Wouldn't creating a partnership then help to stabilize that relationship?

Partnerships with whom? Several different warring tribes that want to gain control over the other or achieve independence? Morocco or Jordan maybe, the rest of them most likely not.

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

#217

Post by petre »

chris1993 wrote: post #161
supergarfield wrote: post #128

Earlier quoted context omitted.

I don't think the main problem here is random terrorists cutting power to Europe by blowing up a power line tower. The real problem is that nation states that control the Sahara haven't proven to be stable (Syria, Egypt), or don't always have great relationships with Europe (Algeria in the 90s). As to points 4 and 5, although storage and some backup capacity is reasonably feasible, this would mean that Europe could v…

It might motivate Europe to improve relations with the region

We'll be better off building nuclear reactors, thank you. The social and political challenges are much lower and so are the risks.

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

#218

Post by petre »

short_sells_poo wrote: post #46
Robotbeat wrote: post #41

Earlier quoted context omitted.

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…

> Where do you propose to put the excess power during sunny days

Heat up some molten salts or any phase change material, then run the steam through a generator. Or pump water uphill. Not very efficient but doable.

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

#219

Post by [deleted] »

WalterBright wrote: post #135
Robotbeat wrote: post #52

Earlier quoted context omitted.

This really is not a big technical problem. You simply don't output the power. This is trivial with any kind of decent power-optimizing inverter setup commonly available today. Solar PV isn't spinning a turbine that needs to find a load. If you disconnect a solar panel, it doesn't damage itself, it just sits there. But I'm sure we'd eventually find uses for this extra energy. Like producing ammonia for agriculture.

You can use the excess to create fuel, such as cracking H out of H2O, and then use that to reduce the nighttime problem. I don't think it'll be hard to find a use for excess power.

[deleted]

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

#220

Post by [deleted] »

ekun wrote: post #156
sfifs wrote: post #111

Earlier quoted context omitted.

The danger is political risk, not necessarily theft or vandalism. Any dependency on territory not under your own societal control can be used to hold you hostage and cannot be depended upon. Forget the solar farm, easiest is to cut power lines. (explosives?)

So we resolve all regional conflicts and unify the world under one country. It's not hard.

[deleted]
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