ratio of coal mines to steam engines

[vanatteveldt]

There are a lot of posts on the optimal ratio of pumps:boilers:engines, but I coulnd't find any post discussing the amount of mines needed to keep these boilers fed.

What I *think* would be the correct number is:

Output per electric miner: 0.525 coal per second * 8MJ per coal = 4.2MJ/s(=4.2MW)
Efficiency of boiler=50%
Output of steam engines: 510KW

So, to power 1 steam engine requires 510/(4200 * .5)=0.24 mines, or in other words just over 4 engines per mine. For a standard 2:28:20 setup, 5 mines should suffice.

Is this calculation correct?

[DaveMcW]

Yes it's correct.

Note that the exact value for coal mining is (60/115), so the exact result is 4.092 steam engines per mine.

[vanatteveldt]

Thanks!

As a somewhat useful corollary, I was curious how many engines a belt can supply (as I sometimes find that I run into trouble if coal is not supplied quickly enough in a long period of heavy use).

A steam engine requires 510KJ/s, a coal provides 4MJ (with 50% efficiency), so a steam engine requires .1275 coal per second.

Using the (rounded down) values from the wiki:

So, if I am correct:

A single yellow belt can feed 13 / .1275 = 102 so just over 100 steam engines.
A single red can feed double, so just over 200 steam engines.
A single blue belt can feed 40 / .1275 = 314, so just over 300 steam engines.

[waduk]

TIL, thanks. This is great.
You should posted this on reddit.

Btw, how about Solid Fuel ?
I did the calculation above using solid fuel, but end up getting confused,..

[BlakeMW]

As a fan of oil power plants, I was wondering the same:

Based on the above:
Chemical plant has crafting speed of 1.25 and solid fuel recipe has crafting time of 3s, so a solid fuel is created in 2.4s (this should be the same for all solid fuel recipes).

Chemical Plant creates 0.417 solid fuel/s, at 25MJ/fuel that is 10.42 MJ/s
Efficiency of Boiler = 50%
Output of Steam engine = 0.510MJ/s

So every chemical plant can support (10.42 * 0.5) / 0.510 = 10.2 Steam Engines, which very neatly is 1 chemical plant for a 1/14/10 running full bore 24/7 with only a tiny amount of fuel left over.

As for belts, it's pretty silly:

Yellow Belt: 318 steam engines
Red Belt: 640 steam engines
Blue Belt: 980 steam engines

The biggest individual power plant I ever built was 800 Boilers, which considering it didn't run often (or actually at all, it was a white elephant) could have been comfortably fed with a single basic belt of solid fuel.

[waduk]

Thanks, ooh that's why i calculate thing wrong, i forgot to convert it into seconds, no wonder my result is weird.

[vanatteveldt]

So how many 0.1/s wells do you need to feed a steam engine via (refining+cracking+)solid fuel, optionally with speed/efficiency modules?

[daniel34]

So how many 0.1/s wells do you need to feed a steam engine via (refining+cracking+)solid fuel, optionally with speed/efficiency modules?

Oil Power Plants, reliable way of making electricity
Also consider using beacons to increase the speed even further.

[waduk]

So how many 0.1/s wells do you need to feed a steam engine via (refining+cracking+)solid fuel, optionally with speed/efficiency modules?

Depends on your petroleum/light/heavy factory setup; whether you use basic oil processing or advanced oil processing ( i guess...)
I have calculation for advances oil processing and solid fuel.

My calculation was way too confusing if i posted it, i'm not good at explaining math (not native english, also i could be wrong about the math).
Anyway, you need 31.25 crude oil/min to produce 25 solid/min per 10 steam engine.

Depleted oil well is producing 0.1/s, so it's 6/min

31.25/6= 5.208

Rounding up, you need 6 depleted oil.

So for 10 steam engine, you need 6 depleted oil, since using 5 is barely not enough.

[vanatteveldt]

Excellent, thanks.

I guess speed (and efficiency?) modules are really needed to make oil power worth it, rk84 (as cited by daniel34) reports running ~8 engines on 2 wells with sp3 modules, of which ~1 is needed for production power. Since the 2-4 depleted wells you often get are quite useless for real oil production due to the hassle of shipping oil, I guess it makes a lot of sense to convert depleted fields to decentralized power plants. I'll experiment with this in my current game

[waduk]

If you can surround a single depleted oil field with 8 beacon, you can actually get 36 or 32.x oil/min on that single oil field.

As reported here :
https://www.reddit.com/r/factorio/comme ... ellsspeed/

But I'm not tested it just yet whether the energy usage is actually negative if we put the beacon with speed modules on them.
But it's good to know.

Yeah probably it's better to use efficiency modules to offset the energy net output.

[vanatteveldt]

re beacons: what is the real electricity use of a beacon? The wiki reports 480W (i.e. half a kW), but that doesn't sound right, or is the main cost in the extra use of the pumpjack?

re efficiency: yeah, especially since the only downside is refinery/chemplant speed, and your depleted field will not likely saturate the processing capacity anyway

[Koub]

The wiki reports 480W (i.e. half a kW)

It's 480 kW (almost half a MW), and almost what a steam engine provides(510 kW)

Beacon

Factorio - Beacon.JPG (23.49 KiB) Viewed 10029 times

[waduk]

480kW, wiki typo i guess. The main page is correct though :
https://wiki.factorio.com/index.php?title=Basic_Beacon

Edit :
Ah, Koub already replying the answer.


Anyway i did some test,at the very minimum (1 refineries, 3 chemical), plus 8 beacon with speed modules 3 (total 16), plus speed modules in single pump jack, it's actually use more energy than it can generate.
They need 5.4 MW (correction : around 4.8 to 5.0MW ) , and 10 Steam can only generate 5.1 MW.

So i guess the Speed module approach is a big no no.

Anyway since we're using 6 depleted oil field instead of 5.2 actually the chem factory can produce a slight more Solid than it needed.
So in the long run it's really good, because eventually you will have more item than needed, stack them in a chest as a backup.

[vanatteveldt]

Thanks (didn't have the game here, so couldn't check)

Well speed modules apparently help quite a bit by themselves, a beacon might be too much unless it can affect multiple (3+?) jacks, but it is quite a high threshold.

If you have "extra" wells, why not simply add more boilers+engines to burn the extra solid fuel?

[vanatteveldt]

(Just putting these calculations down here because I need them, and maybe they will be useful to somone)

In .15, boilers consume 3.6MW of coal (to produce 1.8MW of steam which can feed exactly two steam engines).
Given that a unit of coal has 8MJ energy, a boiler at full capacity requires 3.6/8=.45 coal per second or 27 coal per minute.
A mine still produces .525 coal per second or 31.5 per minute.

So, a fuel yellow belt of coal:
- moves 800 coal per minute
- which requires 800 / 31.5 = 25.4 ~ 26 mines
- and supplies 800 / 27 = 29.6 ~ 30 boilers (and 60 steam engines)
- which require 30*60=1800 water/second
- which can be supplied by 1800/1200=1.5 pumps

In other words, for a full yellow belt coal setup, the ratio is 1.5 pumps : 26 mines : 30 boilers : 60 steam engines

Edit: and a red belt of coal:
- moves 1600 coal per minute
- which requires 1600 / 31.5 = 50.8 ~ 51 mines (40 with +30% productivity)
- and supplies 1600 / 27 = 59.3 ~ 60 boilers (and 60 steam engines)
- which require 60*60=3600 water/second
- which can be supplied by 3600/1200=3 pumps

So, a red belt setup could be 3 pumps : 40-50 mines : 60 boilers : 120 engines [or if you're lazy, 2 pumps : 30-40 mines : 40 boilers : 80 engines, taking from two sides of the red belt]