[0.17.69] - Steam power production differences between turbines & engines

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foamy
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[0.17.69] - Steam power production differences between turbines & engines

Post by foamy »

I'm genuinely unsure if this is a bug, as such, but it does appear to be undocumented:

Steam engines and turbines behave differently under load. Specifically, regardless of what kind of steam is supplied to a turbine, the amount of steam it consumes is proportional to it's maximum power production -- assuming 500C steam. This means it is consuming 3.23333x as much steam if you're feeding it 165C steam than it 'should' be.

For example, suppose your power network is running at 20% load from a nuclear plant. The turbines in the nuclear plant will run at 12 steam/second, as expected (assuming not bottlenecked by supply). Now, suppose you add a single boiler-fed turbine (for the purposes of this exercise, the additional generation capacity can be assumed to be negligible). It does not consume it's steam at 12/second; the game assumes that the turbine needs to be drawing 20% of it's 5.8MW 500C steam output, and so the turbine pulls in >38.7< steam/second.

Functionally, this means that in a mixed nuclear/boiler setup, if you use turbines in both pieces (e.g. for space reasons), the boilers are used preferentially. If the two generators are matched to their appropriate times, draw is split evenly.
Last edited by foamy on Fri Oct 04, 2019 5:16 am, edited 1 time in total.

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Re: [0.17.19] - Steam power production differences between turbines & engines

Post by boskid »

foamy wrote:
Fri Oct 04, 2019 4:25 am
assuming 500C steam
foamy wrote:
Fri Oct 04, 2019 4:25 am
Now, suppose you add a single boiler-fed turbine (for the purposes of this exercise, [...] It does not consume it's steam at 12/second; the game assumes that the turbine needs to be drawing 20% of it's 5.8MW 500C steam output, and so the turbine pulls in >38.7< steam/second.
And what?

https://wiki.factorio.com/Steam_turbine

Boiler will not produce steam with temperature of 500C but only 165C. Because steam turbines consume at most 60 steam/s ratio of boiler:turbine is 1:1. Because of this, 1 turbine connected to 1 boiler when fully loaded will be consuming 60 steam/s (its max) and will produce only 1,8MW because of steam temperature.

If you mix heat exchangers with boilers, steam temperature will be between 165C and 500C and so you will get results in between but energy balance will be conserved

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Re: [0.17.19] - Steam power production differences between turbines & engines

Post by Bilka »

foamy wrote:
Fri Oct 04, 2019 4:25 am
It does not consume it's steam at 12/second; the game assumes that the turbine needs to be drawing 20% of it's 5.8MW 500C steam output, and so the turbine pulls in >38.7< steam/second.
Each steam turbine consumes enough steam to produce 20% of its max output. Whether you are feeding it 125° steam, 165° steam, 500°C steam or 1000°C steam only affects how much steam is consumed to try to reach that 20% production. This is working as intended.

PS: Update your game, 0.17.19 is horribly outdated.
I'm an admin over at https://wiki.factorio.com. Feel free to contact me if there's anything wrong (or right) with it.

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Re: [0.17.19] - Steam power production differences between turbines & engines

Post by foamy »

boskid wrote:
Fri Oct 04, 2019 4:54 am
foamy wrote:
Fri Oct 04, 2019 4:25 am
assuming 500C steam
foamy wrote:
Fri Oct 04, 2019 4:25 am
Now, suppose you add a single boiler-fed turbine (for the purposes of this exercise, [...] It does not consume it's steam at 12/second; the game assumes that the turbine needs to be drawing 20% of it's 5.8MW 500C steam output, and so the turbine pulls in >38.7< steam/second.
And what?

https://wiki.factorio.com/Steam_turbine

Boiler will not produce steam with temperature of 500C but only 165C. Because steam turbines consume at most 60 steam/s ratio of boiler:turbine is 1:1. Because of this, 1 turbine connected to 1 boiler when fully loaded will be consuming 60 steam/s (its max) and will produce only 1,8MW because of steam temperature.

If you mix heat exchangers with boilers, steam temperature will be between 165C and 500C and so you will get results in between but energy balance will be conserved
You misunderstood me. I am aware that a boiler will only produce 165C steam; that's not at all the issue.

The problem is this: Suppose you have, let's say, a thousand turbines hooked up to a nuclear plant. That's a nominal output of 5.8GW, right? Suppose your factory is pulling 580MW. The turbines in your nuclear plant will be therefore be generating 580kW each and drawing 6 steam/sec to do so. Each one is contributing one one-thousandth to your factory's total draw.

Now take one boiler and add two steam engines to it. Take another boiler and add a single turbine. The turbine will still be asked to generate ~1/1000th of the load, i.e 580kW, but because it is fed 165C steam it will pull ~19.4 steam per second in order to hit that target. However, the two steam engines have their target output scaled to ~1/3233th of the the load, and still only draw a combined ~6 steam per second, to produce ~180kW.

That discrepancy in the draw is the point I'm noting. It means that a boiler feeding turbines will hit full steam draw under much lower satisfaction percentages than that exact same boiler feeding steam engines will. Likewise it means that a supplemental boiler steam operation feeding turbines will hit full steam draw long before a nuclear plant in the same power network does.
Last edited by foamy on Fri Oct 04, 2019 5:19 am, edited 2 times in total.

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Re: [0.17.19] - Steam power production differences between turbines & engines

Post by foamy »

Bilka wrote:
Fri Oct 04, 2019 5:12 am
foamy wrote:
Fri Oct 04, 2019 4:25 am
It does not consume it's steam at 12/second; the game assumes that the turbine needs to be drawing 20% of it's 5.8MW 500C steam output, and so the turbine pulls in >38.7< steam/second.
Each steam turbine/engine consumes enough steam to produce 20% of its max output. Whether you are feeding it 125° steam, 165° steam, 500°C steam or 1000°C steam only affects how much steam is consumed to try to reach that 20% production. This is working as intended.

PS: Update your game, 0.17.19 is horribly outdated.
Typo. Should be .69; I've edited the title.

EDIT: And I suppose that answers that question! Guess that means I need to make sure I match up the 'right' types if I don't want to overdraw my boilers :v Could stand to be made clearer on the wiki, though.

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Re: [0.17.69] - Steam power production differences between turbines & engines

Post by MasterBuilder »

It isn't just for steam types too. Power generation is % of max for all producers in a given priority. Steam engines & turbines have the same priority so both are asked to perform at the same % to balance the load.
What the generator has to consume to maintain that percentage is irrelevant.

I know this has basically been answered already bu I wanted to add this as you will have the same effect from modded power generators with the same priority. (All steam is secondary priority.)
Give a man fire and he'll be warm for a day. Set a man on fire and he'll be warm for the rest of his life.

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Re: [0.17.69] - Steam power production differences between turbines & engines

Post by foamy »

MasterBuilder wrote:
Fri Oct 04, 2019 5:29 am
It isn't just for steam types too. Power generation is % of max for all producers in a given priority. Steam engines & turbines have the same priority so both are asked to perform at the same % to balance the load.
What the generator has to consume to maintain that percentage is irrelevant.

I know this has basically been answered already bu I wanted to add this as you will have the same effect from modded power generators with the same priority. (All steam is secondary priority.)
Yah, I worked that out. It's just weird that you can't treat a turbine as effectively equal to two steam engines as a result.

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