Calculating type of belt needed for steam power

[Stephen of Blois]

I'm trying to figure out what type of belt (yellow, red, etc) I need for my set of boilers and I don't know how to go about the calculation.

I've just assumed a yellow belt of coal is enough for 40 steam engines and I think that's true but I don't know how to calculate it. The reason I ask is that once I get more than 40 steam engines I need to know what speed of belt I need and I would like to calculate it.

Is it relatively easy to figure out?

[PunCrathod]

Take the power of the steam engine in watts. Divide it by the fuel value of the item in joules. And now you have how many items a single steam engine uses per second. multiply that by the amount of steam engines and you have the total amount of items you need each second.

Edit fixed the math.

[Stephen of Blois]

Originally posted by PunCrathod:

Take the power of the steam engine in watts. Divide it by the fuel value of the item in joules. And now you have how many items a single steam engine uses per second. multiply that by the amount of steam engines and you have the total amount of items you need each second.

Edit fixed the math.

So I took 900 kW/sec (steam engine output) and divided that by 4 MJ (coal) giving 0.225 coal/sec. Multiply that by 40 and you get 9 coal/sec.

So if I did it correctly, 40 steam engines requires 9 coal/sec?

[Jupiter3927]

You can calculate how fast each boiler will burn through fuel.
Boilers burn through fuel at 1.8MW.
One lump of coal is 4MJ.
Dividing 4MJ by 1.8MJ/s gives 2.222 or 20/9 seconds.

Since each boiler consumes one coal every 20/9 seconds, each boiler needs 9/20 coal lumps every second.
Yellow belts can feed 15 coal/s to whatever so dividing 15/(9/20) gives (15*20)/9 or 300/9 boilers.
This reduces to 33 and 1/3 boilers for a single yellow belt filled with coal.
Red belts would double this for almost 67 boilers.
Blue belts would triple it to 100 boilers even.

To get a specific belt speed...
Do the amount of machines (40) times items needed per second (9/20).
This gives 360/20 or a belt speed of 18 items/s.

[Stephen of Blois]

Originally posted by Jupiter3927:

You can calculate how fast each boiler will burn through fuel.
Boilers burn through fuel at 1.8MW.
One lump of coal is 4MJ.
Dividing 4MJ by 1.8MJ/s gives 2.222 or 20/9 seconds.

Since each boiler consumes one coal every 20/9 seconds, each boiler needs 9/20 coal lumps every second.
Yellow belts can feed 15 coal/s to whatever so dividing 15/(9/20) gives (15*20)/9 or 300/9 boilers.
This reduces to 33 and 1/3 boilers for a single yellow belt filled with coal.
Red belts would double this for almost 67 boilers.
Blue belts would triple it to 100 boilers even.

To get a specific belt speed...
Do the amount of machines (40) times items needed per second (9/20).
This gives 360/20 or a belt speed of 18 items/s.

Thank you for going through this for me - I think I get it.

[shadain597]

Each boiler can consume a maximum of 1.8 MW of fuel, or slightly less than 1/2 a unit of coal per second. That means 40 boilers running at max will consume a bit less than 20 coal per second. Rounding up here is a safe and easy "guesstimate," though 40 boilers x 1.8 MJ = 72 MJ / 4 MJ = exactly 18 coal per second.***

A full yellow belt will move 15 items per second, which means up to 60 MJ worth of coal per second. That's 5/6ths of your boilers' max consumption. You don't want your boilers constantly running at max consumption, because that basically guarantees you'll have brownouts and risk cascading power failure without proper preparations. Personally, if I needed more coal than the yellow belt can transport, then I'd also want to add more boilers/other power production. Though, f you want to play it safe, upgrading to a red belt for the 40 boilers isn't a bad idea.

Remember that, in the event of short power spikes, the steam engines and boilers can still peak at 1.8 or 72 MW total and slowly drain their steam reserves to make up for the inadequate coal supply. At peak, supplied by the full yellow belt, that's a steam deficit of 10/s, so you'd have at least a full minute before power production drops due to insufficient steam reaching the engines. As long as the spike lasts less than a minute (or less than 2 minutes at 66 MW) and drops down enough to let the reserves fill back up between spikes, having the red belt won't make a tangible difference.

Some other stuff worth pointing out:
--Red belts transport items 2x as fast, (or 2x the quantity over the same time period) while blue belts are 3x faster than yellow belts.
--Solid fuel stores 3x the energy that coal does, so a yellow belt could move up to 180 MJ of it at a time, enough to completely fuel exactly 100 boilers.
--Remember that each offshore pump can only provide enough water for 20 boilers/40 steam engines.

***After writing this entire post, I realize that you wrote 40 steam engines in the OP, not 40 boilers. Rather than re-writing it, I'll leave it as-is, because it's still useful, especially if/when you double your power production. To directly answer your question, this means that one mostly full yellow belt can supply the 9 coal per second that 20 boilers/40 steam engines need.

[Jupiter3927]

The game gets a bit more interesting once you figure out how to use ratios and math to engineer your stuff so you have exactly enough to do whatever it is you want.

[Stephen of Blois]

Originally posted by shadain597:

Each boiler can consume a maximum of 1.8 MW of fuel, or slightly less than 1/2 a unit of coal per second. That means 40 boilers running at max will consume a bit less than 20 coal per second. Rounding up here is a safe and easy "guesstimate," though 40 boilers x 1.8 MJ = 72 MJ / 4 MJ = exactly 18 coal per second.***

A full yellow belt will move 15 items per second, which means up to 60 MJ worth of coal per second. That's 5/6ths of your boilers' max consumption. You don't want your boilers constantly running at max consumption, because that basically guarantees you'll have brownouts and risk cascading power failure without proper preparations. Personally, if I needed more coal than the yellow belt can transport, then I'd also want to add more boilers/other power production. Though, f you want to play it safe, upgrading to a red belt for the 40 boilers isn't a bad idea.

Remember that, in the event of short power spikes, the steam engines and boilers can still peak at 1.8 or 72 MW total and slowly drain their steam reserves to make up for the inadequate coal supply. At peak, supplied by the full yellow belt, that's a steam deficit of 10/s, so you'd have at least a full minute before power production drops due to insufficient steam reaching the engines. As long as the spike lasts less than a minute (or less than 2 minutes at 66 MW) and drops down enough to let the reserves fill back up between spikes, having the red belt won't make a tangible difference.

Some other stuff worth pointing out:
--Red belts transport items 2x as fast, (or 2x the quantity over the same time period) while blue belts are 3x faster than yellow belts.
--Solid fuel stores 3x the energy that coal does, so a yellow belt could move up to 180 MJ of it at a time, enough to completely fuel exactly 100 boilers.
--Remember that each offshore pump can only provide enough water for 20 boilers/40 steam engines.

***After writing this entire post, I realize that you wrote 40 steam engines in the OP, not 40 boilers. Rather than re-writing it, I'll leave it as-is, because it's still useful, especially if/when you double your power production. To directly answer your question, this means that one mostly full yellow belt can supply the 9 coal per second that 20 boilers/40 steam engines need.

Thank you for this help. I need to study it, but it will be valuable.

[Stephen of Blois]

Originally posted by Jupiter3927:

The game gets a bit more interesting once you figure out how to use ratios and math to engineer your stuff so you have exactly enough to do whatever it is you want.

Yeah, I have started doing that more and more and it definitely makes the factory run much better, which is really cool. I'm not afraid of the math, but sometimes I hate doing it (and it gets a little complicated) - just want to build... lol.

[Jupiter3927]

I have a spreadsheet built to do all the math for me.
I throw numbers in and it tells me how much I need.
One side calculates how many machines are needed and the other calculates belt speed.

[Psilo]

ignore literally every piece of advice above and use this tool. Thank me later.

https://factoriolab.github.io/list?p=steam*40*3&v=4

you can then figure out the amount of steam engines needed by knowing the ratio of boilers needed to power x steam engines, which if i recall right is 1:2, or use the same logic to find out how many boilers you need, then input that in the tool.

[PunCrathod]

Originally posted by Psilo:

ignore literally every piece of advice above and use this tool. Thank me later.

https://factoriolab.github.io/list?p=steam*40*3&v=4

you can then figure out the amount of steam engines needed by knowing the ratio of boilers needed to power x steam engines, which if i recall right is 1:2, or use the same logic to find out how many boilers you need, then input that in the tool.

Op asked how to calculate it. That tool does not really help with that. The calculation also isn't complicated and op already got the correct answer here.

Originally posted by Stephen of Blois:

So I took 900 kW/sec (steam engine output) and divided that by 4 MJ (coal) giving 0.225 coal/sec. Multiply that by 40 and you get 9 coal/sec.

So if I did it correctly, 40 steam engines requires 9 coal/sec?

Also if there are mods involved that tool will just give you the wrong answer. But if you learn how to calculate it yourself it takes all of 5 seconds to calculate the correct answer.

[Jupiter3927]

It really does only take 5 seconds once you have the equations ready to go.

[PunCrathod]

Originally posted by Jupiter3927:

It really does only take 5 seconds once you have the equations ready to go.

Funny thing is you don't even need to remember any equations. You Just need to know that watts are actually just joules per second and apply some basic math. I learned all this back in highscool years before factorio was even a thing.

[knighttemplar1960]

Originally posted by PunCrathod:

Originally posted by Jupiter3927:

It really does only take 5 seconds once you have the equations ready to go.

Funny thing is you don't even need to remember any equations. You Just need to know that watts are actually just joules per second and apply some basic math. I learned all this back in highscool years before factorio was even a thing.

With Factorio you don't even have to do that. Just keep adding machines until you saturate the output or use up all of one of the inputs.

[PunCrathod]

Originally posted by knighttemplar1960:

Originally posted by PunCrathod:

Funny thing is you don't even need to remember any equations. You Just need to know that watts are actually just joules per second and apply some basic math. I learned all this back in highscool years before factorio was even a thing.

With Factorio you don't even have to do that. Just keep adding machines until you saturate the output or use up all of one of the inputs.

True. But learning more complicated things is fun too.