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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

#161

Post by chris1993 »

supergarfield wrote: post #128
antisthenes wrote: post #95

Earlier quoted context omitted.

Absolutely. The infrastructure is very fickle, but also enormous on the scale of countries. Since we're talking about hypotheticals, I could say these things are also true: 1. There are counter-drones deployed and patrolling air space above the towers. 2. There are hundreds of independent power lines with 2N redundancy, so cutting 5-10 high voltage lines would do nothing. 3. The undersea cable points are protected by…

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

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

#162

Post by encoderer »

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…

Or a single car bomb?

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

#163

Post by extrapickles »

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…

You can do things with the excess power that otherwise would be un-economical to do during a cloudy day. Things like smelting aluminum, desalinating water, etc take massive amounts of power.

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

#164

Post by olleromam91 »

prewett wrote: post #120
spdionis wrote: post #67

Earlier quoted context omitted.

Are you sure? This is a recurring theme in your arguments but I don't necessarily agree with you. What are the reasons for you to think that?

We already have things that float in the ocean for long periods of time (ships, oil rigs) and which withstand ocean storms, so it seems like a solved problem compared to fusion.

And people could...idk...work on solar rigs to maintain these systems!

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

#165

Post by andrewwharton »

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…

The undersea cables don't need to be cut, they're perfectly capable of breaking on their own.[0]

[0] https://en.wikipedia.org/wiki/Basslink#2015-2016_outage

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

#166

Post by sbierwagen »

ChuckMcM wrote: post #150
sbierwagen wrote: post #147

Earlier quoted context omitted.

https://dothemath.ucsd.edu/2012/03/space-based-solar-power/ >At this level, our 3.6 km diameter collecting area would generate about 40 GWh of energy in a day, at an assumed reception/conversion efficiency of 70%. By comparison, a flat array of 15%-efficient PV panels occupying the same area in the Mojave Desert would generate about a fourth as much energy averaged over the year. So these beaming hotspots are not ter…

Grid delivery. You cannot easily move power from the desert into urban centers.

Well, you sure can't point the power delivery beam at downtown LA either.

And the footprint of the rectenna array is enormous-- Tom assumes a 100GHz transmit antenna 30m wide, which means the downlink antenna has to be 3.6km wide! And this is the minor axis-- the solar array has to be geosynchronous orbit, which means any receiving antenna not on the equator has be an ellipse.

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

#167

Post by kirrent »

theptip wrote: post #81
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…

> How exactly do you propose to get that electricity from the desert to say Finland? High voltage DC transmission works fine for this problem. All of the engineering challenges have been credibly worked out and priced ( https://en.wikipedia.org/wiki/Desertec ). The main problems with this approach are political, in that it requires massive cooperation between many countries over very long time scales (decades). Why i…

Not sure why you're being downvoted. The Chinese are actively researching in the area of ultra high voltage DC transmission so that power can be distributed long distances from remote renewable resources. Even if the problem were as simple as a direct link from the Sahara to Finland, China has already built UHVDC transmission lines half that length. UHVDC technology is only improving with time and it's an exciting field to watch.

The economist had a reasonable article, though light on technical detail: http://www.economist.com/news/science-and-technology/2171432...

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

#168

Post by theptip »

sfifs wrote: post #111
theptip wrote: post #81

Earlier quoted context omitted.

> How exactly do you propose to get that electricity from the desert to say Finland? High voltage DC transmission works fine for this problem. All of the engineering challenges have been credibly worked out and priced ( https://en.wikipedia.org/wiki/Desertec ). The main problems with this approach are political, in that it requires massive cooperation between many countries over very long time scales (decades). Why i…

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?)

Europe is currently highly dependent on Russia's natural gas for their electricity; I don't see this as worse. Indeed, better to diversify your power imports.

(Better still to generate locally, but not every country has the land available to do so).

https://en.wikipedia.org/wiki/Russia_in_the_European_energy_...

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

#169

Post by FridgeSeal »

cletus wrote: post #82

I've been hearing about and hoping for fusion power since probably the 1980s. The more I think about it the more I think it's probably a pipe dream. The idea appears so simple an elusive: combine Hydrogen into Helium (and there are variations that use Helium, particularly He-3 as a fuel), which releases energy. Hydrogen is essentially limitless (He, particularly He-3, less so). Stars do it all the time. The two big p…

One of the reasons it's still failed to eventuate is that the engineering and scientific challenges are significant and funding for fusion endeavours is already quite limited and has been declining. The benefits from fusion are insanely good (I have read that in an energy-producing reactor, you would only need ~250kg of deuterium to power the US for a year), so it would be foolish to relegate it to 'pipe dream' status just because of the current difficulties. It just needs continued effort and investment.

The 2 main issues are addressed in another couple of comments [0], [1]

Burning fuel is easy, of course it's going to stick around, but for maximum efficiency and power generation capabilities, you can't really go past fusion.

[0]: https://news.ycombinator.com/item?id=14205346 [1]: https://news.ycombinator.com/item?id=14203704

> At this point I'm honestly not convinced that this is an economically solvable problem.

The energy industry as it is, is belligerent and seemingly resistant to new technologies that aren't fossil fuel based. How long would this remain the case if actual concerted (gov, scientific and industrial) effort was dedicated to fusion rather than pissing it up the wall trying to hold on to fossil fuel based approaches for mass scale power generation.

> It's not sufficient to output more energy than you input either.

The science says otherwise, if this was the case we wouldn't even be bothering to get power out of it.

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

#170

Post by novalis78 »

marcgcombi wrote: post #62
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…

Bump to Robotbeat. Fission reactor designs, with many clever advances in safety, have never been tested because of the lack of support from U.S. DoE. Pilot-scale reactors are expensive, but would really help to advance our working knowledge of these new technologies. Overall, nuclear fission has gotten a bad wrap. As for the cost of storage, that was worked out 20-30 years ago via the Yuca Mountain facility. If one o…

Thorconpower is a case in point. They tried very hard to get their experimental reactor off the ground in the US but their pilot project seems to have moved to Indonesia instead now. That's a shame - Thorium and molten salt reactor experience and technological mastery would be extremely useful for solar system space colonization efforts past the orbit of Earth (insolation levels fall dramatically and a lot of basic industrial chemical engineering off planet will encounter abundant raw materials but will also need easy access to enormous quantities of energy). Fissiln is so worthwhile pursuing and it's reputation so bad it will probably need an Elon Musk type persona to tackle it.
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