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Old 02-25-2018, 03:19 AM   #31
johndallman
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Default Re: [Spaceships] Antimatter Factory

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Originally Posted by RogerBW View Post
That's essentially what I do in Wives and Sweethearts (TL11 with mild superscience): antimatter factories as close to the star as they can be put and still survive, and freighters that shift the stuff around to where it's needed. Most systems have their own factories.
I think of this as the "standard" way of making antimatter in quantity when there isn't blatant superscience. I first encountered it in Vernor Vinge's novel Marooned in Realtime (1986), but it may be older.
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Old 02-25-2018, 09:42 AM   #32
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Default Re: [Spaceships] Antimatter Factory

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Originally Posted by AlexanderHowl View Post
If you really want to make antimatter affordable though, you need to make energy very cheap and the process very efficient. Right now, the wholesale cost of electricity is $30/MW-h (3.6 GJ), so the electricity required to make one gram of antimatter at 50% efficiency (the hypothetical maximum efficiency) would cost $750,000. At TL9, the efficiency is only 0.00833%, meaning that the electricity cost should actually be around $9 billion per gram (the cost is $25 billion per gram in Ultra-Tech, but I think that the electricity is the majority of the 'materials' for the productive formula).
The 25 billion is the "retail" price so it should include things like the transport and guarding of the dangerous material to the point of sale and of course profit for the maker and seller. So on that it seems fairly reasonable with the given production price.


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In order to make it as affordable as in Spaceships, you would need to either increase the efficiency by 32X and decrease the cost of electricity by 32x.
It should be noted that in Space ships the highest energy production/dollar put into production machinery is achieved with TL8 fission. The more advanced systems costs more/power point.

So taking a say SM 11 fission reactor for $100 million, and the 1.5% costs for maintenance, bank loans and other costs makes the costs $1.5 million/month.

SM 11 power point seems to be 10 GJ weapon shot every 20 seconds for normal weapon and one every 10 seconds for improved, so assuming normal is 25% efficient and improved 50%, that is 40 GJ/20 seconds or 2GW.

So the power plant would produce 24*30*2 GW-h/month= 1440GW-h or 1.44 million MW-h for that 1.5 million cost. So one on site power production using space ships prices would give a cost of just over $1/MW-h.

So that is a *30 improvement in cost for the electricity, we would then only need additional efficiency to cover the cost of the AM production facility, profit, transporting and such over your 0.00833% efficiency to reach spaceship prices. Say an efficiency increase of order of magnitude *2 to *8 maybe.
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Old 02-25-2018, 06:53 PM   #33
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Default Re: [Spaceships] Antimatter Factory

Energy is insanely cheap in Spaceships. The price of the fission reactor is $0.1/W, which is ridiculous cheap, considering that non-mobile fission reactors are 10/W. Solar panels are also laughably cheap at $0.16/W, considering that they cost $5/W before you subtract an average of $3.50/W in grants and tax incentives given by the federal, state, and local governments in the USA. In reality, SM+10 fission reactors should cost $3 billion, not $30 million, and solar panels should have a cost $1.5 billion at SM+10, if you do not receive subsidies and grants.
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Old 02-25-2018, 09:13 PM   #34
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Default Re: [Spaceships] Antimatter Factory

If you use the posters' estimates of power points, then you hit the problem of solar panels producing far more energy as would be realistically available. They're obviously written to make them slightly competitive with fission reactors, etc.
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Old 02-25-2018, 09:37 PM   #35
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Default Re: [Spaceships] Antimatter Factory

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Originally Posted by Flyndaran View Post
If you use the posters' estimates of power points, then you hit the problem of solar panels producing far more energy as would be realistically available. They're obviously written to make them slightly competitive with fission reactors, etc.
The power to weight ratio isn't absurd -- it's probably easier to get 1 kW/kg out of solar than it is out of nuclear. The problem is size. A SM +5 ship (30 tons, 1,500 kW) needs at least 1500 square yards for 1 pp. The actual cross-section of a SM +5 ship is probably something like 75 square yards, to get 1500 square yards you need to go up to SM +9, and realistic efficiencies result in it being about SM +11. This gets worse as you go up SMs -- a decent rule of thumb would be to multiply SM by 1.5 and then add 4, rounding up, for the SM of the solar array.
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Old 02-25-2018, 09:50 PM   #36
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Default Re: [Spaceships] Antimatter Factory

If we use an estimate of 30 kW of electricity production per metric ton of spacecraft mass per power point, the minimum realistic size of a solar panel would be around 120 square meters per metric ton of spacecraft per power point at TL8 (assuming 19% efficiency) or 60 square meters per metric ton of spacecraft per power point at TL9+ (assuming 38% efficiency). If we also assume a minimum mass of 0.75 kg per square meter, the minimum mass for a SM+10 solar panel should be around 900 metric tons at TL8 (two components per power point) or 450 metric tons at TL9+ (one component per power point). Anything less robust than 0.75 kg per square meter (75 milligrams per square centimeters or the same mass as a postage stamp per area) will probably not survive any meaningful acceleration.
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Old 03-05-2018, 10:07 PM   #37
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Default Re: [Spaceships] Antimatter Factory

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Originally Posted by AlexanderHowl View Post
Energy is insanely cheap in Spaceships. The price of the fission reactor is $0.1/W, which is ridiculous cheap, considering that non-mobile fission reactors are 10/W. Solar panels are also laughably cheap at $0.16/W, considering that they cost $5/W before you subtract an average of $3.50/W in grants and tax incentives given by the federal, state, and local governments in the USA. In reality, SM+10 fission reactors should cost $3 billion, not $30 million, and solar panels should have a cost $1.5 billion at SM+10, if you do not receive subsidies and grants.
But that comparison is a little like comparing the price of getting elemental aluminum in 2018 to the price of in Napoleon's time. Relative costs change as technology advances.
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Old 03-06-2018, 08:13 AM   #38
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Default Re: [Spaceships] Antimatter Factory

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Originally Posted by AlexanderHowl View Post
If we use an estimate of 30 kW of electricity production per metric ton of spacecraft mass per power point, .
This is missing a core problem with solar in Spaceships (though Anthony skirted around it).

Spaceships' adoption of mass as its' sole significant measurement makes the fuel/delta-V issues work out right for realistic drives. However no formula basing solar power generated on mass will work out right. Solar power should be based on surface area and not mass.

As ships get larger their ratio of surface area to mass will shrink so attempts to use solar power will require increasingly large arrays added on. Historical/Real World spacecraft have relied on unfolded arrays anyway rather than panels covering only the outside hull.

As with most of Spaceships realism issues it arises out of trying to extend a marginal/niche real world technology to give it general usefulness. Most users would never encounter the problems.
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Old 03-06-2018, 09:48 AM   #39
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Default Re: [Spaceships] Antimatter Factory

I always assume that Solar Panel Array are deployable arrays that retract during combat and planetary operations.
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Old 03-06-2018, 10:46 AM   #40
Fred Brackin
 
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Default Re: [Spaceships] Antimatter Factory

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Originally Posted by AlexanderHowl View Post
I always assume that Solar Panel Array are deployable arrays that retract during combat and planetary operations.
What would the vessel do for power then?

<shrug> I went back and checked and all the basic rules text says is that a Solar Panel Array is an exposed system and is not protected by armor. There certainly didn't seem to be anything about it changing the vehicle's SM.

So not a fantastically realistic design option and I wouldn't use it as a source for hard numbers.
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