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HoI4 Dev Diary - Fuel Review and Motorized Artillery

Hello and welcome back for the first dev diary of 2019! Today we will update you on the state of fuel as well as show you a little something many people have wanted for a long time.

Changes and Updates to the Fuel Implementation

When the game launched, oil was used as other resources for the purpose of production. This was an abstraction done for fuel consuming equipment. We have removed this abstraction but are still using a simplified version of what happens in the real world. Oil refining was and is not as simple as simply processing it into a multipurpose “fuel,” but we felt that this simplification was necessary for gameplay and consistency of depth of detail.

We have added fuel as a resource to the top bar. With this UI element we convey a few bits of information. The numbers show the amount of time you have before being full or dry. Here the number is green and indicates that the stockpile will be full in 361 days. The numbers will become red if fuel is being lost. The green bar indicates the state of the stockpile, showing how full it is. The arrows indicate that fuel is currently being gained.

top bar fuel.png


Oil is still traded as it was previously but is no longer used in any production. Instead, excess oil is converted to fuel at an hourly rate. The trade UI has had some slight updates to take this into account. What was formerly the “production” category is now “need.” Oil now has special subcategories of this section. Active need and potential need are now represented with “A” and “P,” explained more thoroughly in tooltips. This helps give the player an understanding of how much oil needs to be traded if they wish to try and cover their current fuel needs with a constant supply from oil refining.

fuel trade ui DD.png


Refineries have also been changed from giving Oil resources to giving hourly fuel. This both makes more sense from a historical perspective and makes it easier to control how much resource is produced by refineries. Previously, tech increases could only allow for a minimum increase of a single unit of oil. This gives developers and modders much better granular control over the output of a synthetic refinery.

For countries that will not have enough fuel production during wartime to meet their needs, developing a healthy stockpile is an option. Most nations will not start with a large stockpile capacity. Stockpile potential will be reduced by economy laws for many nations. Also, increasing stockpile capacity requires some investment, and will take space away from industry through the production of silo facilities. Japan is a good example of a nation that may run into a situation during the war when their usage far outstrips their potential fuel gain, so they will need to have a decent reserve of fuel if they want to fight the US in the Pacific.

fuel_1.jpg


To help understand what is going on with your fuel stockpile and to manage distribution when fuel has become tight, we have added fuel as a special section to the logistics tab. This includes a breakdown of usage by military branch of the military and the ability to control who gets priority for fuel distribution. A special variant of the stockpile menu used for other equipment shows a breakdown of fuel consumption by day, month, and year as well as a breakdown of the state of the stockpile over time.

fuel stockpile menu.png


The logistics support company has also been changed and will help with keeping your armor fuel usage more manageable.

image (1).png



Motorized Artillery Units

When Hearts of iron 4 was released, it featured a very large number of possible battalion types that you could use to design your divisions. However, there were a few unit types that were pointedly absent. For example, if you wanted to make a motorized infantry division that was a faster version of your regular infantry division with line artillery - you couldn’t, unless you were okay with slower speed.

Part of the reason for this was the feeling that a motorized artillery unit didn’t have enough of a drawback to be a meaningful choice - it would just be better than regular artillery, and the added cost of a handful of trucks was not a major issue if you were building trucks anyway.

mot_arty_1.jpg


With the addition of fuel, that has changed. Now it is a long-term decision to motorize more of your force, and it requires more planning as your army suffers increasing penalties if you can’t meet fuel demands. So we decided to add motorized artillery units in regular artillery, rocket artillery, anti-air and anti-tank flavors. They are, by and large, identical in firepower to their horse-drawn versions but require 50 trucks each, have a roughly 50% bigger supply footprint and, of course, require fuel to run properly.

mot_arty_2.jpg


No special tech is required to unlock motorized artillery; having motorized equipment and the respective artillery type researched also unlocks the motorized unit.

That’s all for today, tune in next week when we talk about changes to research and show off the new naval tech tree!
 
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Why should it? Historically synthetic fuel represented about 2-5% of all global fuel available during the war. The remaining 95%+ all was refined from natural crude oil.

It's already silly how Germany can produce 20% of the global oil through synthetics in current version of the game, that would be impossible to do in the real war. Should be considerably reduced if anything...

Ok, "all over the world".
But how was it specially in Germany?
 
Solid additions and changes;
What determines the size of the stockpile aside from silos?
I recall in the previous DD on fuel that this was dependant on a number of factors:
The size of your national stockpile will depend on the number of states and their infrastructure, your economic law and if you have built Fuel Silos.
Does the size of a state determine the capacity?
Will building infrastructure everywhere increase your stockpile?
If so, I hope it is dependant on the size and population density of the state.
 
Ok, "all over the world".
But how was it specially in Germany?

At it's peak roughly half of consumed fuel was from Synthetic and half from imports from Romania/other smaller oilwells. So in HoI4 that would be maybe around 50-70 oil from Romania and as many from Synthetics, but the Synthetic fuel could not be made into as high octane aviation fuel for example, and had other limits making it not quite as good as the real thing.

In HoI4 you can comfortably reached 350 oil all from synthetics as Germany by investing a bit in it, so many time the historical maximum possible, and 2 years earlier as well.
 
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The addition of fuel will enhance the logistic and strategic feeling of the game. Very good!

Will it be possible to conduct raids against enemy fuel deposits, or has that been covered in previous DD's?

Strategic bombing. I would suspect you can target fuel silos just like anything else.
 
I wonder how fuel consumption is affected by "active" units. In other words, units engaged in movement or fighting. Do they use more fuel, or would that complicate the system too much? I'd be a little paranoid about my usage rates if I had to worry about that. There's a trade-off between realism and fun somewhere in there.

I'm too curious how this new fuel mechanic will effect volunteer forces, will it be withdrawn from the participant's fuel reserves, or the host's?
 
Will I still be able to blanket build refineries as Germany and have a gross over-abundance of both fuel and rubber?

Or do refineries only process oil into fuel, rather than create oil themselves? They were used for both irl.
 
ah mama!
 
I like the new motorized Icons. If possible, and since I don't think it would be that hard of an addition: an optional Motorized infantry icon in the same style would be nice! ...Possibly some other mini-motorized icons as well. I'd personally love to have it to differentiate my motorized and mechanized armor divisions
 
At it's peak roughly half of consumed fuel was from Synthetic and half from imports from Romania/other smaller oilwells. So in HoI4 that would be maybe around 50-70 oil from Romania and as many from Synthetics, but the Synthetic fuel could not be made into as high octane aviation fuel for example, and had other limits making it not quite as good as the real thing.

In HoI4 you can comfortably reached 350 oil all from synthetics as Germany by investing a bit in it, so many time the historical maximum possible, and 2 years earlier as well.

Yes. Players know they will need to prepare well ahead for losing access to the oil producing regions if the world, and so they do so; this hindsight was not available to the real leadership of the real nations involved in the war, hence, reality had a much smaller investment in synthetics.
 
Yes. Players know they will need to prepare well ahead for losing access to the oil producing regions if the world, and so they do so; this hindsight was not available to the real leadership of the real nations involved in the war, hence, reality had a much smaller investment in synthetics.

Synthetic Fuel needed enormous amounts of coal. If real leaders had invested more they would be stupid because there was no more coal left for Germany to convert, so they wouldn't have gotten any more fuel.

This is well modelled if you play for example the HoI2 spinoff Arsenal of Democracy since "energy" is an actual resource Germany runs out of with too much investment into Synthetic Fuel.

I agree that HoI4 has plenty of "hindsight" problems but Synthetic Refineries actually isn't one of them.
 
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Awesome changes! Are there any plans to rebalance strategic bombing because it can be really broken sometimes (ok, most of the time)? Also, since many axis countries will most likely have a lot of problems with fuel, will tanks be made stronger?
 
The logistics support company has also been changed and will help with keeping your armor fuel usage more manageable.
Wait, don't those use trucks as well? Will that be accounted for or will those trucks consume no fuel?
I was under the impression that the logistics company were the abstraction for a motorized army (in the sense of the supply lines being motorized, not motorized divisions per se) where, for example, Germany might not have the fuel (previously oil) to field those trucks and so keep a horse based supply line, while someone like the UK or US would likely have more than enough of it.

Why is that, figures there should be a distinction here, no?
 
Refineries have also been changed from giving Oil resources to giving hourly fuel. This both makes more sense from a historical perspective and makes it easier to control how much resource is produced by refineries. Previously, tech increases could only allow for a minimum increase of a single unit of oil. This gives developers and modders much better granular control over the output of a synthetic refinery.
Do I understand it right that that your "surplus oil" (own extraction + import -export) converts automatically into fuel (without the need of additional buildings) and the synthetic refineries add some fuel ontop of that?
 
If oil is not used for production anymore, having excess oil means that you get positive fuel gain from oil recourse or you can sell the oil if you wish? What about having negative oil? It gives negative fuel gain from oil resource?

I suspect "negative oil" just means you have unused refinery capacity. There's no downside except lost opportunity. Excess oil will probably just be traded away as usual to nations with more refineries than oil.

well
- by bombing infrastructure you lower the amount of oil that can be refined as infra level affect how much is gained there
- by bombing synth refinieries you lower gain from them
- bombing actual silos reduces storage spaces which may remove fuel also

Sorry to keep asking questions but given that we can bomb out our enemy's ability to refine oil, does that mean we can also trade for fuel directly?