Oil is a vital resource for fueling ships, aircraft, or tanks. Vehicular units continuously use around 0.1 - 30 units of oil, making it an essential material for a large military composed of vehicular hardware.
During the initial stages of the game, most militaries have limited vehicle resources, and therefore, the importance of oil may not be as significant. However, as the game advances, players gradually expand their military capacity by constructing additional tanks, aircraft, and ships, resulting in a higher demand for oil.
Almost every nation that has more than one city produces oil, and every nation starts out with five units of oil. Players can construct mines and infrastructure in cities that produce oil, which will double (or quadruple if a city has a combination of a fully-powered mine and max infrastructure level) the output of oil in those cities, and research enhanced fuel efficiency in the technology tree, reducing fuel consumption up to +60%.
Oil Deficit and Shortage
Oil Deficit
This event occurs when more units of oil is being consumed than the amount that is produced. Fortunately, all units will function normally as long there is still existing oil. However, one should be wary of long-term oil deficit, especially if the amount of oil consumption is substantial.
Should this occur, an "OIL DEFICIT" warning will appear until the deficit is cleared.
Oil Shortage
This event occurs when the oil stockpile has been completely depleted due to an oil deficit, causing tanks to rapidly suffer from attrition and eventually disappear. Both ships and planes will experience significant reductions in attack and defense performance, along with slower mobility. Once the shortage is resolved, reinforcements will begin to heal the damaged units; however, manpower will significantly decrease if a large number of units were harmed by the shortage.
Should this event occur, an "OIL SHORTAGE" notification will pop on the screen, while the "OIL DEFICIT" warning will disappear, as there is no more oil reserved in the stockpile to lose.
Ways to Prevent Oil Deficits and Shortages
See "Oil Production Tips" section to view all methods to evade an Oil Deficit or Shortage.
Oil Production
Trading Oil
Oil can be produced or traded just like every other resource.
Press on the flag on the corner on your screen, then select the Economy interface on the menu that should come up, press 'Resources' on the bottom-right corner of the economy tab, select Oil, then you can trade your national reserves, supply, and other countries' supplies. After typing the amount of oil you want to buy, press the buy button, and you get a confirmation message.
Oil Production Tips
- Always maintain a positive oil circulation as oil deficit can lead to an oil shortage, which will negatively impact with devastating problems to one's military if the depletion is not resolved as soon as possible.
- If you are consistently experiencing an oil deficit when utilizing a large military, especially during war, it is suitable to bulk buy a heavy amount when trading with other nations rather than purchasing regularly. This is to avoid negating a significant percentage of your income. It is completely fine to be in an oil deficit, just watch out for a shortage.
- However, if you cannot handle the oil deficit burden even with trading, then simply disband a portion of oil-consuming units until the burden is sustainable.
- Ensure to research fuel efficiency in technology as it reduces the oil upkeep for military units.
- You can build mines and infrastructure in oil-producing cities to double (or quadruple if a city has a combination of a fully-powered mine and max infrastructure level) the production of oil in those cities, as well as researching the mineral extraction branch for a larger output. Additionally, the Chief Geologist and the Corporate Representative leaders, policies, formable modifiers, national modifiers, and more can also significantly enlarge oil production.
- Do not recruit a large navy, air force, or tank army when oil is scarce or cannot afford to refuel the oil stockpile through trading with other nations.
- Annexing oil-rich nations, such as
Saudi Arabia, can significantly expand oil production and reserves. - The 'Public Service Act', the 'Grant Illegal Prospecting Licenses', 'Forced Labour for dissidents', and the 'Transport Act' policies can boost the production of oil, while the 'Power Generation Act' consumes a considerable amount of oil, depending on the nation's total population.
Oil Production Chart
A list showing countries that produce the most oil to none. It should be noted that this chart excludes any form resource production modifiers, including starting infrastructure.
Click [Expand] to view the chart, and click [Collapse] to close the chart.
Fuel Efficiency
There are some methods to efficiently reduce oil consumption per five seconds (one tick), besides corruption.
| Type | Modifier | Efficiency Change |
|---|---|---|
| Technology | More Refined Fuel | +15% |
| More Efficient Engines | +20% | |
| Better Fuel Compounds | +25% | |
| Formable Modifiers | Dawn of the Rising Sun -  Empire of Japan
|
+25% |
| Corruption | Depends on corruption amount (0% - 100%) | Decreases (1x - 0.5x) |
Trivia
- Oil was the first resource to officially appear in the game, which was implemented during the Oil Update.
- Within the game, Saudi Arabia is depicted as the foremost nation in terms of oil production. However, in the real world, the
United States holds the top position as the largest oil producer in terms of domestic production, producing around 14 to 15 billion barrels per day,[1][2] with Saudi Arabia ranking #2, and when counting reserves, Saudi Arabia is still 2nd while 
Venezuela has the most by a diminutive margin.