Why 10-25 times net power?

Discuss how polywell fusion works; share theoretical questions and answers.

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KitemanSA
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Post by KitemanSA »

MSimon wrote:The amount of investment per unit of net power out is dependent on the gain.
If direct conversion is possible it will be low. If a steam plant is required it will be high.
The actual value is TBD.
Folks, in such discussions, pronouns are everything, and capitalization runs right behind.

"If direct conversion is possible it will be low." What will be low, investment or gain?
djmelfi wrote:If you can produce 200mw from a $200 million investment you have a viable plant.
I am sorry, but 200milliwatts fro $200 Million is rediculous. Now 200MW is something else. :roll:

TallDave
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Post by TallDave »

If I started up with fossil fuels and then switched to my own generated energy, the fossil consumption stops and I am now generating NEW energy constantly as this continues WITHOUT ANY FOSIL FUEL INPUT, the energy I produce and recylcle is not part of the COST. My 25-100% gain eventually represents 1000s% gains over the fossil fuel input which has ceased.
Yes, but what you're missing in this analysis is that fuel is not the primary cost for nuclear power (fusion or fission) the way it is in fossil fuel extraction. Most of the cost for nuclear power is the plant.

In fact, even for fission, you could have 10x price increases in fuel and barely change the end cost. For fusion, it matters even less.

The problem with ITER-style tokamaks as a commercial notion is that the plant power density of even the most advanced designs lags well behind fission plants -- by orders of magnitude. This means it can probably never compete with fission reactors, and fission fuels won't run out for at least 1,000 years and possibly much longer.

93143
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Post by 93143 »

chrismb wrote:Can you please just state what made-up numbers you have an issue with?
50 MW drive power on a 100 MW reactor. Where did that come from? Granted we don't yet have enough data to actually refute this number, but it's not an estimate I'd put money on, especially for a D-D plant...

Or how about 5000 MW fusion power, 750 MW net? I've never seen those numbers before. Granted that wasn't you, but still...
If you put 100MW in and get 303MW out and after converting that 301MW you get 101MW power again 100 of which goes back into the machine, then you've got a net of 1MW.
If that's not "making up numbers for the sake of argument", I don't know what is. The point is not to have something that can technically make net energy; it's to have something that works better than other ways, so somebody will actually build it. That's the answer to the original question in this thread, and I'm given to understand you don't actually disagree with this...?

Yes, you might want this for a moon base if you couldn't get anything else, but we're not talking about moon bases, and in any case you CAN get something else - fission and solar are both better options for a moon base than a polywell with a system gain of 1.01...
We can play that game if you like and you would loose
It's not a question of 'loosing'. Please, give me a bit of background. It's very hard to tell where you're coming from, why you say some of the things you do, and what I can expect you to know about. Sometimes you seem very well educated and trained, sometimes... not.
You were talking about steam-based turbines, then you went from there on to something about making up numbers
Yes, I "went on". The jump was clearly labeled; did you miss it?

None of your comments have even mentioned heat engine efficiency or employed the concept in any way, so you have no excuse for suddenly pulling out Carnot in this context.

I was the one who pointed out that Carnot (or more accurately Rankine) is where the approximate factor of 1/3 comes from. This is one of the two factors that require such high raw fusion gains in a D-D plant. The other is that steam-based conversion equipment is very expensive, and this cost is not related to the net fusion power - it's related to the gross fusion power, because a polywell requires pure electrical drive, not a combination of electrical drive and ash heating like a tokamak.

...I thought you didn't even disagree with MSimon on this. Why the sarcasm?

TallDave
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Post by TallDave »

50 MW drive power on a 100 MW reactor. Where did that come from? Granted we don't yet have enough data to actually refute this number, but it's not an estimate I'd put money on, especially for a D-D plant...
At one point I actually asked the question of how much drive power a D-D 100MW reactor would need, and iirc Nebel said somewhere else they were estimating about 5MW.

Mike Holmes
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Post by Mike Holmes »

The "It" is the initial investment.

This seems pretty simple to me, but then I probably have it all messed up. Let's see using some simplified exaples like the ones used:

Steam Plant
--------------
Power Req: 100 MW
Power Produced: 300 MW
Net Output: 200 MW
Potential Profit: $200 M
Cost to Build/Maint: $100 M
ROI: 200%

Inefficient BFR Plant
-------------------
Power Req: 300 MW
Power Produced: 500 MW
Net Output: 200 MW
Potential Profit: $200 M
Cost to Build/Maint: $300 M
ROI: 66%

Note that the "Power Required" for the coal plant represents fuel costs, and other operational expenses mostly, not recycling electricity through the plant. And we're ignoring the actually non-trivial cost of the fusion fuels (purified Boron isn't exactly cheap, it's just power-dense in this use).

Is this your argument, MSimon? That the plant basically costs more to build and maintain than current technology, for the same output? Wheras:

Efficient BFR Plant
-------------------
Power Req: 100 MW
Power Produced: 500 MW
Net Output: 400 MW
Potential Profit: $400 M
Cost to Build/Maint: $100 M
ROI: 400%

This is the rate at which it's economical, because it's more efficient than current technology, in terms of Return on Investment? Is that it?

It seems that the question, then, is really what the cost will be, per unit of input power. That's the unknown, right?

Mike

MSimon
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Post by MSimon »

TallDave wrote:
50 MW drive power on a 100 MW reactor. Where did that come from? Granted we don't yet have enough data to actually refute this number, but it's not an estimate I'd put money on, especially for a D-D plant...
At one point I actually asked the question of how much drive power a D-D 100MW reactor would need, and iirc Nebel said somewhere else they were estimating about 5MW.
If that is what he was working with for a pB11 reactor he is planning on plant operation at the resonance peak. Which I believe (as does Roger) is a very wise choice. Control will be tricky but I think it is doable.
Engineering is the art of making what you want from what you can get at a profit.

TallDave
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Post by TallDave »

Mike,

You're conflating different kinds of numbers there; some are ongoing costs, some are one-time costs, etc.

What you might typically do as an investor is calculate everything at net present value, then figure out if you can profitably sell electricity by comparing the rates of current electricity producers (perhaps using those rates to calculate the NPV of all the electricity you expect the plant to produce over its lifetime, then comparing to the NPV cost). You can then divide the difference by the number of years the plant will operate to get a rough annual ROI.

An inefficient plant would have negative ROI, because you're losing money on every kWh you sell. No one likes negative ROI :x .

Given the risks and unknowns, as a private investor you'd probably want very high ROI for a project like this.

In addition to the cost of operation (input power) the major relative unknowns would include: will it work at all, if so what % of the time will it be operational, what are the maintenenance costs, and what is the initial capital outlay to build the fusion portion of the plant. It's not too hard to figure out from this what the acceptable parameters for those variables are, such that the plant would be profitable.

Mike Holmes
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Post by Mike Holmes »

Dave,

Yes, very much I'm simplifying. That was intentional (I didn't want to have to post a link to a massive spreadsheet). I'm trying to understand what the unknowns are, specific to a BFR. Yes, as Rodney Dangerfield's character from Back to School would inform us, there are going to be costs we're not considering like how much you have to pay to grease the palms of the local zoning board. And so on and so forth.

Those are endemic to any project. What's important here is how the ratio of input to output power (so we're assuming it works) affects the ROI, and at what level that ratio has to be to make it a good investment. So I'm letting some terms drop out for the moment.

I agree that the initial ROI will have to be high. As the unknowns become known more, however, that ROI will drop, of course.

Mike

Damon Hill
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Post by Damon Hill »

This thread is getting frustrating.

Is it not understood that a reactor doesn't earn money until it delivers electricity to the grid? A reactor that produces 300 MW of thermal energy doesn't get paid for >that<, it gets paid for the fraction that can be converted into electricity--and the conversion equipment is a significant part of the investment and operating cost.

That's the attractive feature of p-B11 and Polywell--it delivers a far higher fraction of its energy as electricity by completely bypassing thermodynamics!
That's downright revolutionary, if it can be made to work and scaled up to meet the market demand.

But what I'm seeing here is a fundamental lack of understanding that heat is not electricity, yet the assumption appears to be that it is.

MSimon
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Post by MSimon »

Steam Plant
--------------
Power Req: 100 MW
Power Produced: 300 MW
Net Output: 200 MW
Potential Profit: $200 M
Cost to Build/Maint: $100 M
ROI: 200%

====

Let me see if I can do better:

Coal Fired Steam Plant
--------------
Electrical Power Req: 110 MWe
Thermal Power Produced: 350 MWth
Electrical power consumed in production (plant air [100psi], lubrication pumps, etc.) 10 MWe - 30 MWth
Thermal power for plant operation (feed water pumps, cooling water pumps, etc) 20 MWth
Net Output: 100 MWe
Cost of funds to build the plant:
Average interest rate over the life of the plant:
Fuel costs:
Maintenance costs:
Personnel costs:

Now of course the above is very rough. More like orders of magnitude. But it gives a better idea of the inputs that have to be considered.
Engineering is the art of making what you want from what you can get at a profit.

MSimon
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Post by MSimon »

Damon,

Excellent point.

If direct conversion can be made to work the costs of the conversion eqpt are very low compared to a steam turbine and can be 95% efficient. Not counting the losses from collection.

The other thing you gain from direct conversion is that the production flow for the eqpt is about 6 mos. to 12 mos. Steam turbines take 36 mos to build from order to delivery. Then you have delivery and installation time which can be another 12 to 18 mos.

During all that time your capital is tied up you are paying people and no income. So add that to your capital budget.
Engineering is the art of making what you want from what you can get at a profit.

chrismb
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Post by chrismb »

Damon Hill wrote: That's the attractive feature of p-B11
That's the cobblers of p11B. The alphas come off at all sorts of energies, in two bunches of distributions. So what potential do you set your 'energy recovery grids' to, to be able to capture such 'ranges' of particle energies? Do you try to slow down the median of the lower range and leave the higher range to barrel on through and strike the vacuum vessel, thereby sputter-contaminating it, or do you set it to the higher voltage so the lower range particles get pushed back into the reaction volume?

Heck, it can't even be shown as an effective energy transfer mechanism with a mono-energetic beam of particles intentionally formed by an ion gun to prove the idea!

Why not just start blithering on about anti-matter interstellar propulsion while you're at it. Direct energy recovery from fast p11B ions is blithering, twiddling, utter-and-complete, undemonstrated, lacking-in-fundamental-understanding-of-the-engineering, can-only-be-imagined-in-the-mind-of-a-theoretical-inventor, nonsense.

Please proceed with a few facts to prove me wrong on this. I am truly hungry to see some real engineering demonstrations and information on this process.

djmelfi
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Post by djmelfi »

MSimon wrote:Damon,

During all that time your capital is tied up you are paying people and no income. So add that to your capital budget.
WoW is that the way an engineer ties up his money 100% up friont? It's called PLANNING and personell dont stand around and money isnt drwan down till needed. I'ts called LETTER-OF-CREDIT.

Regardless of your self induged cudos, you havnt made much sense on any economic subjects. Under your guidance no plant would ever get built and no one would ever invest $2.4 billion in a 1400MW Nuclear plant (THEY DO AND MAKE A LOT OF MONEY).

I just wish someone would jump on this thread who was interested in moving it forward. That is, can we scale a BFR Boron, self feeding (use its own energy) , that has enough energy to grid to get 100MW per $100million investment?

Regardless of all the hype, that is what power plants do, 100MW per $100million investment. I find it intuitively comfortable to believe operating costs of a BFR would match or beat a Gas fired steam turbine plant. particularily a Boron direct capture device.

To do this we need to understand the

1) energy output scale of a BFR per size of reactor. ENERGY to grid. and COST of scaling up.

1.5meters = 100MW. $200Million.

3.0meters = 500mw $400million (guesstimates showing energy increase favorable to investment increase)

4.0metes = 1000mw $600million.

If a 1.5 meter produces 100mw (and I dont understand if that is NET NET, it is gain but I dont understnad if it is to grid.) and cost 200million.

Then what does a 3meter produce and cost?
If the scale of cost goes up higher than the scale of energy then this dosnt work.

If the scale of cost goes up slower than the scale of energy then there is a viable commercial scale.

You are trying to make rocket science out of a simple principle.
In Search of conservative principles

93143
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Post by 93143 »

djmelfi wrote: You are trying to make rocket science out of a simple principle.
You aren't listening. No one is saying a 100 MW plant won't make money. What we're saying is that a 100 MW plant won't make money if it needs to generate 5000 MW and use 4900 of that to power itself. This is because that 5000 MW costs a lot of money to build (especially thermal), and the market return on 100 MW over the plant lifetime is peanuts in comparison. (Yes, chrismb, I'm making up numbers for the sake of argument. Note that I'm not claiming they're valid, nor does my argument require them to be; see below.)

It is also true that a BFR that powerful with a system gain that low is not plausible if EMC2 is anywhere near right about how they operate. So don't worry about gain; worry about whether it will work at all.

If it works at all, power and gain will both almost certainly scale much faster than capital cost. Barring scale-dependent confinement phenomena, gain should go as the fifth power of the radius, and power as the seventh. Unless capital cost manages to scale faster than linear with power output, which I doubt, it should be quite reasonable to expect a profitable plant somewhere on the curve, and 100 MW is looking pretty comfortable.

There was an article recently (on DailyKos IIRC) that took the number 1.2 from Wikipedia (the ratio of bremsstrahlung to fusion power for a thermalized p-11B plasma) and somehow managed to misinterpret it as the target gain for a p-11B BFR. Is that what's bothering you?
chrismb wrote:Heck, it can't even be shown as an effective energy transfer mechanism with a mono-energetic beam of particles intentionally formed by an ion gun to prove the idea!
Can't? Or hasn't been? They are two different things. No one has needed it until now. Same with QED-type engines; the power source has been missing so no one bothered.

I'm not saying it will work. I'm not trying to minimize the challenges. But we don't need people like you badmouthing the concept just so you can say "I told you so" in the event it winds up not working.
can-only-be-imagined-in-the-mind-of-a-theoretical-inventor
Dr. Bussard designed, built, and fired nuclear rocket engines. They worked. Apollo (and NERVA) got cancelled before they could be used as upper stage engines for the second-generation Saturn V. What makes you think you know better than him?

Damon Hill
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Post by Damon Hill »

Why not just start blithering on about anti-matter interstellar propulsion while you're at it. Direct energy recovery from fast p11B ions is blithering, twiddling, utter-and-complete, undemonstrated, lacking-in-fundamental-understanding-of-the-engineering, can-only-be-imagined-in-the-mind-of-a-theoretical-inventor, nonsense.

Please proceed with a few facts to prove me wrong on this. I am truly hungry to see some real engineering demonstrations and information on this process.[/quote]

I'm still waiting to see polywell demonstrate some useable output power of any sort, but the whole principle of p-B11 fusion is that the output is in helium ions (which I assume is what you actually meant to say) instead of neutrons and gammas and whatnot that have to be slowed down and their energy harvested as thermal energy, and then thermodynamically converted to electricity with substantial waste heat.

I imagine direct conversion will be one of the engineering challenges, but why is it "nonsense"? It seems a very elegant solution. D-T fusion in a tokamak seems very inelegant to the point that I'd rather work with advanced fission technology.

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