• We have updated our Community Code of Conduct. Please read through the new rules for the forum that are an integral part of Paradox Interactive’s User Agreement.

Dev Corner | Thermodynamics

If you missed the previous Dev Corner, check it out here!


Briefing: Thermodynamics
Author:
@Zwirbaum


Hello everyone!

It has been eight days since the last dev corner, which means it is time for another one. Last time, I was talking about some of the new naval concepts and changes coming to the Hearts of Iron IV. Today I will be talking about the introduction of Coal and Energy into the game. As a casual reminder keep in mind that everything discussed here is in a relatively early stage, and as such is subject to change.I also want to add that not every dev corner will be a long one, and some may end up on a rather short side. But without further ado, let’s keep this lump of coal rolling.

For the first time since the launch of the game we will be adding a new resource to the game, as every other resource, Steel, Rubber, Tungsten, Chromium, Aluminium and Oil were since day 1 in-game (with Oil getting Facelift in Man the Guns to be used for Fuel production instead of equipment production). This resource is Coal - to put it very briefly it will be serving as a ‘fuel’ in the form of Energy for your industry to keep it running efficiently.

Core Concept
What are some of the goals when it comes to adding Coal & Energy, and what do we want to achieve with it?
  • We want to introduce a potential soft-limit on the current almost limitless industrial expansion.
  • Increase importance on expanding and securing a resource base for your needs.
  • Provide a bit more interesting choices when it comes to economic laws, give some incentive for a player to consider ‘demobilize’ at some point during the gameplay, and that War Economy / Total Mobilization is not always the one and the only one right choice.
  • We are not aiming at creating a super complicated or overly complex system for energy/economy model

What is all the fuse about?

dc_thermodynamics_001.png

Sardinia starts with 2 units of Coal at the beginning of the game. As usual, numbers are subject to change, so please do not despair yet.

Base Concept
So the system works like this: Coal is excavated just like every other resource in-game. Each unit of Coal that you have for your own use (so not traded away) will produce a set amount of Energy, which then in turn is used to power up your industry - your civilian, military factories and naval dockyards, which for the ease I’ll be later calling them in this dev corner as ‘factory’. Each Factory, regardless of the type, has the same base Energy demand, so what you are seeing in the top bar as your industry size should also give you a very rough estimate of the demand.


dc_thermodynamics_002.png

This totally mysterious country, that is totally unrelated to Sardinia from the previous screenshot starts with 56 factories, and now has a mysterious bar under the factory count.

Economy of the Scale
However the base Energy demand is not everything, as each Factory you own will also introduce a little extra scaling cost to the demand per factory, so a small, undeveloped minor country will be able to sustain their few factories with a rather small amount of coal, while historically accurate Luxembourg spanning across Eurasia will require much more energy in order to effectively satisfy the ever hungry maw of their Industry.

Lower Mobilization Law is your friend?
Most, if not all, economic laws will also have factory energy consumption modifiers, which will essentially either increase or decrease how much each factory (including the ‘scaled’ portion from ‘size’ of the industry) will demand energy. Higher mobilization laws will have higher energy demand, to represent longer working hours, more shifts etc.

dc_thermodynamics_003.png

Economy Law picker will also now proudly display the energy consumption modifier at the first glance, so that you do not need to scour through the tooltip to find the modifier. Before you start going crazy with guessing what is the second number, it is just the expected amount of consumer goods - the icon is currently placeholderish, as we haven’t adjusted the previous icon yet.

How does it work though?
I will start with a quick reminder how the Civilian, Naval and Military Industry operate in-game currently. Essentially each of the ‘factories’ have a specific base amount of output valued in points that they contribute daily to. (5, 2.5 and 4.5 respectively). And that was further modified by all the technologies, laws, ideas, ministers, national spirits with various ‘Construction Speed’ or ‘Dockyard/Factory outputs’ modifiers. I am not mentioning Production Efficiency, as that was unique to the Military Factories.

So how will that operate in the brave new world? We will now have a base output for each of the industry types - which means that regardless of the energy, you will always have at least this much output from your factories. And there will be ‘fully powered’ output values for the industry. Depending on the energy ratio you are providing, you will end up somewhere on that scale, e.g. If you have 50% energy - you will be getting output that is ‘50%’ way from the base output to the fully powered up. All the previously mentioned Construction Speed, Dockyard/Factory Output modifiers will also be scaled accordingly to the % of the energy you have.

dc_thermodynamics_004.png

This is the current debug display that allows us to see energy demand & consumption, and how much it impacts the industry. In this case we have 26.7% energy needs satisfied, and it means that each of our CICs provide 4.2 IC daily, MIC provides 3.7 IC daily and NIC provides 2.1 IC daily. Of course as usual, reminder that all values are subject to change.

Wrapping Up
And that is all from this dev corner. While this post is one the shorter side, impact from adding this ‘system’ could of course be quite big - however thanks to covering only this one matter, feedback, opinions, suggestions from you dear readers, should be laser-focused and allow us to get a much clearer picture of what you are thinking. Anyways, that is all from me for this week, and next week Thomas will be back with more things to say about the Factions.

Thanks for reading, and until next time, farewell!

/Zwirbaum
 
  • 87Like
  • 35Love
  • 8
  • 8
  • 6
Reactions:
Definetely an interesting addition, but it would be good to know how this new system will interact with other energy-related content in the game:

1. Some advisors (industrialists and ministers related to energy production);
2. Mining and energy related industrial concerns;
3. Nation-unique content (national spirits, decisions, the "Electrification" mechanic of Afghanistan).

Also, as others have already said, it will be really cool if Coal resource interacts with other mechanics, like fuel production or coal-powered ships. At least, I hope that some coal cost will be added to logistics. Maybe logistics could even be made to require Fuel proportional to amount of trucks and convoys and Coal proportional to amount of trains...
 
  • 7Like
  • 1
Reactions:
It sure sounds interesting. A bit early though, to really make my mind about it. But while you´re at it... will you rebalance the other resource(quantities) along the way too?
I made a few points about it here: Resource talk

Thanks for reading,
Cheers
 
  • 2Like
Reactions:
I really like the idea as long as it does have enough impact for meaningful trade offs. I like the idea of soft capping industry, late game can feel a bit silly to me.

My only big question is balance around all the games systems and meta reactions, I am always torn on oil. I feel its to abundant in HOI4, rarely do you need to restrain a German offensive for oil...but balancing the historically OP USA for a fun game must always be hard.

I wonder how most people find energy play and 'feel' from the mods that have it?
 
You can always go back all the way back to the days before Man the Guns, even. 1.5.4 - Cornflakes.

Or you can write a mod, or not load the DLCs you don't want to see.

You have lots of choices, but I doubt Paradox is going to rewrite it's newest DLC just because you don't like a new feature. Just roll back to older stuff if you want simpler.

View attachment 1326222
You can go even further back, all the way to 1.0, if you do some extra steps. https://forum.paradoxplaza.com/forum/threads/how-to-roll-back-your-game-version.1121392/
 
This feels very unbalanced to say the least, and it feels like they’re addressing the disarmament problem of endgame from the exact opposite direction that they should be.
A good catch. It's not clear to me how this mechanic accomplishes that at all. For one it does nothing about the fact that units and equipment simply exist forever with no maintenance. The winning side is almost certainly going to have vast stockpiles of equipment in reserve. For another, on second look, with power being evenly distributed I'm not sure how the increasing power cost of war eco is supposed to encourage you to demobilize. Either you can eat the cost or you can't (in which case why bother going war eco at all?). Also, just on a conceptual level, WW2 was the Total War. There shouldn't really be a reason in a historical game not to switch over (unless they introduce political factors). Basically every nation that could go to a total war economy did and the one big exception which delayed doing so, Germany, quite famously lost.
 
  • 5Like
  • 1
Reactions:
There's two major things which I would like to see in the game. The first is relevant to this: could you please revise the amount of states in the US and possibly in other nations like the UK and the Netherlands? Newer nations have an increasingly large amount of building slots, while other nations remain behind. Especially the US suffers from this, being hardcapped on industry in 1941 in most games.

The second is the German armament miracle. The pressure the four year plan puts on the prewar economy is historical, but as the war dragged on into 1942 Germany fully mobilized the economy and doubled or even tripled its output of aircraft and tanks. Germany should be able to take the autarky focus after at least 1 year of war with the US and Soviet Union regardless of the resource situation.
 
  • 3Like
Reactions:
I like these changes so far, more economic depth is always welcome for me!


Others already suggested it, but I also would like to have a way of controlling energy distribution!

Maybe tie it to the chosen economy?
For example you have 3 sliders: Civ, Mils, Naval.
Depending on your chosen economy, slider values can be set between these values (ofc pseudo values without any viable balancing):

Civil Economy
Civ: 50-100%
Mil: 0-30%
Naval: 0-30%

[...]

War Economy
Civ: 20-60%
Mil: 0-80%
Naval: 0-80%

etc.

This would make it way more meaningful to change to certain economies, depending on your "goals".


Additonaly I'd love to see infrastructure getting more important with these udpates.
For example, I'd like to see energy distribution also modified by the states infrastructure leve like +15% distributed energy per level.


E.g: 100 power is available to the state after all calculations. The state has 2 civs, 1 mil, 1 dockyard and distribution civ/mil/naval is 50/30/20


Infrastructure level 0 = 25% "Distributed energy":
civs in this state gain 12,5 energy
mil 7,5
naval 5

Infrastructure level 5 = (25% + (15% * 5) = 100% "Distributed energy":
civs in this state gain 50 energy
mil 30
naval 20

(Or you'll calculate it the other way around that you have 2 civs at x% max energy etc.)


This way it is way more strategic important where you plan/build your industry and it becomes a lot more important where you try to strike at your enemy.
Para Trooper Raids or strategic bombing of dense industry states would now be a lot more rewarding/punishing.


Last but not least while you are at it: Please add some way to grow our population, even if it's by a tiny bit!
My idea some time ago was to give infrastructure and civs a small bonus on population growth for a state, something like:

Infrastructure:
It's easier and faster for people to move around with good infrastructure. Thus they find more time for family.
+0.25% monthly population growth in state per level

Civs:
People find more work places and civil goods for daily need in this state
+0.25% monthly population growth in state per civ
 
  • 3Like
Reactions:
Could you please add the ability to give land to liberated/other nations in peace conferences? It would help a lot doing "realistic" things. Also other fun thing would be to make weaker nations able to "steal" land from countries who are having a civil war.
This or literally have Yalta or Potsdam decisions matter.
 
  • 1Like
Reactions:
Plese unify resource excavation into a single mechanic, instead of a bunch of focus trees mixed together with decisions and base values, as many others pointed out. Also, stockpiling resources could be a thing too, because having a new resource as coal implies more interacting with the extremely old trade and resource system.
 
  • 2Like
Reactions:
Right now Dams and Civilian Nuclear Reactors provide a reduction in the energy factories from this state are using. (Local Energy Consumption Modifier), so let's say if the modifier would be -25%, then factories located in such state instead of consuming 100 energy would now consume 75 energy. (Random numbers are random)
Good solution.
To make raids more interesting, I'd increase the %. If the dam only feeds one state, should its impact be greater (50%?)
 
Booooooo. I didn't like thermodynamics in college and I don't like it here. If people moaning about coal despite it being unnecessary in game gets it added why hasn't my moaning about research slots been added either?
 
  • 1Like
Reactions:
Nuclear reactors only reducing energy consumption sounds good since it's not their primary effect, but I think dams should provide actual energy worth several imports of coal.

At the moment, dams provide negligible bonuses and even if dams reduced local energy consumption by 100%, I fear that a dam raid's overall impact on e.g. Germany's economy would be small and not worth the aerodynamics breakthrough required to unlock it, since it only adds a handful of factories to the energy bill.

(Alternatively, make dam raids available without having to spend a breakthrough, so you can do them for flavor/roleplay.)
 
  • 4
Reactions:
Uranium would be a resource that probably does not matter at all until ~1942/1943, and it's importance only increase (or even skyrocket) after that date, making it a resource that is completely ignored for the first half of the game. I'm not a fan of adding a resource that could matter only in some runs.

What about consumer goods as a tradable good that causes stability to drop when you are below a threshold that is influenced by both economic mobilization laws and war support?