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Wendelstein 7-X: Gigajoule energy turnover generated for eight minutes

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Re: Wendelstein 7-X: Gigajoule energy turnover generated for eight minutes

#51

Post by drannex »

fizigura wrote: post #37
karmajunkie wrote: post #30

This is perhaps an obvious question to some, but I'll ask it anyway: How is the power generated here converted into usable electricity? I know for conventional fission reactors the heat of fission is basically used to run a steam turbine. Given the extreme heat of the plasma, and that it must be magnetically suspended so that it doesn't even touch the sides of the containment, how is that heat transferred to some oth…

They currently run a bad-ass heatsink (which is one of the main challenges of this project, i.e., how to cool it), but eventually you will use that heat to convert it into electricity, yes. For the German-speaking crowd here, the Alternativlos podcast guys were there twice and had lengtly conversations with the researchers there. Like, between nerds. Really cool, if you understand the language. https://alternativlos.…

Omega Tau also visited and talked with some of the researchers and has a great podcast episode on it (and truth be told, all of their episodes are great).

https://omegataupodcast.net/312-the-wendelstein-7-x-fusion-e... (from 2019, 3Hrs, English)

Re: Wendelstein 7-X: Gigajoule energy turnover generated for eight minutes

#53

Post by KyleBerezin »

fizigura wrote: post #46
KyleBerezin wrote: post #18

Earlier quoted context omitted.

Yea, but compare the financial burden of that compared to a solar farm of the same output. Not to mention the technical risk.

Solar farms on farmland? That won't scale to the energy needs of 8bn+ people if we still want to keep feeding them. Especially a non-vegetarian diet.

I'm just saying the money doesn't back the idea yet. I'm not anti-fusion.

Re: Wendelstein 7-X: Gigajoule energy turnover generated for eight minutes

#54

Post by Guvante »

fizigura wrote: post #41
ladams wrote: post #9

Earlier quoted context omitted.

Stellarators in particular suffer from very long development cycles. It takes years and years of research to develop the algorithms used to optimize the coil geometries, and then the production of the coils and assembly of the vacuum vessel within the coils is much more challenging than for a tokamak. The coils are hard to produce because they have highly irregular shapes, and tight tolerances. Assembling the vacuum…

For a few billion USD you could build a real power plant of this type. Sounds expensive, but consider how much money nuclear fission did cost initially, and how much money we burn on other stuff, then it's not unthinkable to have somebody rich chip in and make it happen. (Germany just gave $10bn subsidies for a domestic Intel factory.)

They managed to handle what a fission reactor outputs every second in this experiment.

I don't think that points to a commercial reactor whenever someone spends a few billions.

Re: Wendelstein 7-X: Gigajoule energy turnover generated for eight minutes

#55

Post by sp332 »

jahnu wrote: post #31
t0mas88 wrote: post #28

Earlier quoted context omitted.

For less than 15 billion euro you could buy enough solar to power a country the size of the Netherlands. With 5 billion to spend on batteries you might even make it through night time usage. Or in other words: Fusion is too expensive at this point to be useful.

That seems amazingly cheap! Are we really down to that low level of cost?

Grid-scale solar is $33/MWh (+) https://emp.lbl.gov/publications/utility-scale-solar-2022-ed... and the Netherlands uses 1,000,000,000 MWh/year https://ourworldindata.org/energy/country/netherlands so it's only off by a factor of ~2.

(+) These numbers are for the USA. I found a mention of a cheaper project in Chile https://about.bnef.com/blog/cost-of-new-renewables-temporari... but I don't know what the situation is in Europe. And wind might be even lower.

Re: Wendelstein 7-X: Gigajoule energy turnover generated for eight minutes

#57

Post by runako »

amelius wrote: post #24
aidenn0 wrote: post #8

What is "energy turnover" in this usage? [edit] Found it: "Energy turnover is defined as the amount of heat multiplied by the duration of the discharge[1]." By "amount of heat" I assume they mean "heating power delivered to the plasma" b/c the the only way to multiply by time and get Joules is to start with power. 1: https://gigazine.net/gsc_news/en/20230227-wendelstein-7-x-en...

Isn't this similar to the monetary meaning of the word turnover? Like turnover : profit energy turnover : net energy output?

Possibly the poster is from a country like America where "turnover" is not a preferred term to refer to gross receipts of a business. (Americans typically use "revenue" instead.)

Re: Wendelstein 7-X: Gigajoule energy turnover generated for eight minutes

#58

Post by alkonaut »

amelius wrote: post #24
aidenn0 wrote: post #8

What is "energy turnover" in this usage? [edit] Found it: "Energy turnover is defined as the amount of heat multiplied by the duration of the discharge[1]." By "amount of heat" I assume they mean "heating power delivered to the plasma" b/c the the only way to multiply by time and get Joules is to start with power. 1: https://gigazine.net/gsc_news/en/20230227-wendelstein-7-x-en...

Isn't this similar to the monetary meaning of the word turnover? Like turnover : profit energy turnover : net energy output?

So when this had a turnover of 1.3 GJ (361 kWh), was that with a net loss in the end? How much electricity did they put in?

Re: Wendelstein 7-X: Gigajoule energy turnover generated for eight minutes

#59

Post by tsimionescu »

karmajunkie wrote: post #30

This is perhaps an obvious question to some, but I'll ask it anyway: How is the power generated here converted into usable electricity? I know for conventional fission reactors the heat of fission is basically used to run a steam turbine. Given the extreme heat of the plasma, and that it must be magnetically suspended so that it doesn't even touch the sides of the containment, how is that heat transferred to some oth…

Most of the answers are missing the actual (proposed) mechanism.

The energy of the reaction is mostly carried away as high-energy neutrons. So, the way to get energy back is to "capture" those neutrons. Since neutrons are not electrically charged, you can't use them to directly create electricity, so all you're left with is using them for heat.

Unfortunately, since they are electrically neutral, they're also relatively hard to catch. You need a dense material where they will have a good chance to hit some nucleus. The proposed designs are typically some kind of liquid metal blanket being circulated around the reactor and onto a place where it can boil water to produce steam to spin a turbine. Lithium is the metal most proposed for this, since it also has the advantage that it can produce tritium when bombarded with neutrons (tritium being the super rare half of the fuel that goes into the reaction).

Re: Wendelstein 7-X: Gigajoule energy turnover generated for eight minutes

#60

Post by aquafox »

aquafox wrote: post #56

Interesting fact: Nuclear fusion, even if we'll make it work, won't stop global warming, because the heat it creates heats up the earth enough to bring us outside the Paris agreement: https://twitter.com/rahmstorf/status/1605967891928596481

Why the down votes? What is factually wrong with that statement?
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