The supply chain in Cities:Skylines involves the production, processing and selling of various forms of "stuff" and the necessary transportation to allow this to occur. The flow of cargo through a city is as important as the flow of people.
In theory a city's supply chain can exist in complete isolation from the outside world, but in practice it is necessary to allow for exports and imports to deal with excesses and shortfalls of supply. There are various different types of cargo and cities very commonly have large volumes of imports and exports simultaneously.
- 1 From production to sales
- 2 Power plants
- 3 Transportation
- 4 Imports and exports
- 5 Policies
- 6 Industries DLC
- 6.1 Units and Materials
- 6.2 Production and Storage
- 6.3 Transport
From production to sales
Assuming no import or export, a unit of cargo will pass through four different buildings in its "lifetime"; a primary producer, a secondary processor, a (tertiary) generic processor, and a shop. This complete supply chain requires specialized industry for the first two steps, generic industry for the third, and commercial zoning for the last.
There are four types of raw materials: agricultural materials, forestry materials, ore, and oil. Raw materials are produced by the appropriate regions of specialized industry, when it is zoned in areas with the appropriate natural resource. Buildings which produce raw materials are easy to identify visually.
Raw materials cannot be used directly by goods-producing industries. Instead these raw materials need first to be processed. There are different processing buildings for the different types of raw material and these will only occur in zones of the relevant specialized industry. A few secondary processing buildings will emerge in areas where primary production occurs, and if specialized industry is zoned in areas without the appropriate natural resource it will consist entirely of these buildings.
If the scattered secondary processing buildings in areas of production are insufficient to process the produced material, you may wish to deliberately zone specialized industry in resource-free areas to develop more secondary processing capacity.
Generic industrial buildings require occasional deliveries of the different types of processed resource. It appears that a generic industrial building will occasionally demand a delivery of a random resource. In aggregate, a large zone of generic industry will require an approximately steady supply of all four types of processed resource.
All generic industry produces appropriately generic units of "goods".
Buildings in commercial zones receive "goods", which allows them to operate and service customers.
An exception to this supply chain are the coal and oil power plants which consume, respectively, unprocessed ore and oil.
The most basic form of transportation of cargo is via roads. There are a variety of different cargo-transporting vehicles in the game, and there a specific vehicles for each kind of specialized industry. A vehicle which transports cargo is always owned by the delivering building; these vehicles will return to their facility once they have completed deliveries. Vehicles will only supply cargo from one building, but may deliver cargo to several customers in one round of deliveries. When viewing a delivery vehicle's info window you can see its % load, and what proportion of its load it drops off at each building.
Because the routes of cargo and people are different, a well-designed city will be able to separate the traffic of both, reducing the likelihood of congestion and intolerable noise pollution. Applying the heavy traffic ban policy to districts is one way of controlling the routes of industrial traffic. Another, is to zone commercial areas in the middle of the map, residential and industrial areas on either side of the commercial area, separating commuters and goods.
Cargo terminals are effectively public transportation for cargo, providing fast high-capacity transport options for cargo that reduces the burden on the roads. Cargo harbors, although primarily ports for imports and exports, can also be used by cargo for intra-city transportation. Road transport is required to transport cargo to and from these buildings - with the notable exception of the Cargo hub added in the After Dark expansion. Vehicles sent from a terminal or harbor will be owned by that building and will need to return to the facility once deliveries have been completed.
If transport problems result in cargo being unable to reach their destinations industry and commerce will not be able to function and will become abandoned.
Imports and exports
If there is an excess or shortfall at any point in a city's supply chain, for any sort of product or good, the supply chain can be supplemented with imports and exports from outside the city. These can be done via four ways:
- By road - vehicles will use the outside highway connection. Note that both importing and exporting vehicles will need to go back to where they came from after completing their delivery.
- By rail - cargo will be loaded to/unloaded from trains at cargo terminals. Trains that come into the city to import cargo can be loaded with export cargo for the return journey.
- By ship - cargo will be loaded to/unloaded from ships at cargo harbors. Like trains, a cargo ship can do both imports and exports.
- By cargo planes - cargo will be loaded to/unloaded from planes at cargo airports.
There is no revenue directly accrued to the city budget from exports, nor is there a cost to the city treasury for industry/commerce importing cargo (other than the maintenance cost of cargo transport facilities). However importing or exporting goods is effectively missing out on tax revenue of the city that could have been earned had these goods been produced/processed/sold within itself.
The imports and exports of individual buildings, color-coded by type of product, can be viewed in the 'Outside connections' info view. This info view also brings up import/export statistics for the city as a whole.
At a per-building cost to the city treasury, the "Industrial Space Planning" policy doubles the goods production of industrial buildings, doubling the effectiveness of the affected buildings and their employees in contributing to the supply chain (this can also be considered as halving the number of buildings and jobs required to fulfill the same supply function). "Big Business Benefactor" and "Small Business Enthusiast" do the same for sales in high- and low-density commercial buildings respectively. When considering whether to enact these policies, mayors should also consider that these will double the per-building freight burden on the transport system.
Industries added the ability to make industrial zones with a supply chain completely controlled by the player. The four specialized industries are all still in play. Products still graduate from raw materials to processed materials to finished goods. But now the player must balance supply rates and storage with building expenses and transportation.
Instead of painting a district and specializing in one of four industries, the player paints an Industry Area and places a headquarters main building to specialize the zone. Access is then given to a basic extractor, processor, and storage unit. The zone levels up as jobs are filled and materials produced, unlocking new extractors, processors, storage units, factories and auxiliary buildings.
Units and Materials
Each zone has one raw material and 2 processed materials associated with it. Those processed materials are then combined in unique factories to create finished goods. Buildings will list a production rate in thousands of units but storage and info screens will talk about tons or barrels. All materials are treated the same with 1,000 units equaling 1 ton or barrel.
|Raw Forest Products||Forestry||raw material||20|
|Planed Timber||Forestry||processed material||150|
|Animal Products||Farming||processed material||150|
Production and Storage
Raw materials are stored in buildings specific to each type of industry unlocked as a zone levels up. A grain silo will always store crops. Processed materials are stored in generic warehouses unlocked as a city grows. A warehouse can switch from storing plastics to flours. Both of these buildings can be placed anywhere.
Raw materials are produced by extractors at a rate determined by the resource abundance where they are located and capped by a max production rate specific to the building. Processors produce processed materials from raw materials at a rate specific to each building. These buildings must be placed in an industrial zone of the appropriate specialization and are unlocked as the zone levels up. The production rate of these buildings increase as a zone levels and can be increased further with workers barracks. The storage of these buildings can be increased with maintenance buildings.
Unique factories produce goods from processed materials at a rate specific to each building. That rate can be decreased to 50% normal or increased to 150% normal. This does not affect storage in the building but does affect upkeep. These buildings can be placed anywhere but only one of each type may be on a map.
Processors and unique factories have internal storage for their inputs and outputs that are directly related to their normal consumption and production rates. The storage is listed as a rounded whole number of tons. Storage equals eight more than twice the weekly consumption or production rate. So if something produces 3,200 units per week, that is 3.2 tons which means it's output storage is displayed as 14 (8+2*3.2=14.4). Normal consumption is always a multiple of .8 tons per week and can be calculated from the input storage. Normal production is always listed on the buildings information popup.
All values are for original production rates. This is changed as zones level up and with worker's barracks in the zone. Output is in tons per week. Profit takes into account upkeep but not water nor electricity. Larger extractors cost more per ton extracted but smooth out production by shipping fewer trucks at a quicker interval. For instance, 7 small tree plantations have the same weekly output as 3 large tree plantations but the small tree plantations will send out 7 trucks roughly every 12 days while the large send out 3 trucks every 5 days.
Raw Forest Products
|Building||Output (ton)||value/ton||Output (value)||Upkeep||Profit/Week||Price/ton|
|Small Tree Plantation||4.8||20||96||8||88||1.67|
|Medium Tree Plantation||8||20||160||24||136||3|
|Large Tree Plantation||11.2||20||224||40||184||3.57|
|Small Tree Sapling Field||6.4||20||128||16||112||2.50|
|Large Tree Sapling Field||9.6||20||192||32||160||3.33|
|Small Crop Field||4.8||84||2.50||2.63|
|Medium Crop Field||8||132||3.50||2.06|
|Large Crop Field||11.2||184||3.57||1.44|
|Small Fruit Field||4.8||84||2.50||2.63|
|Medium Fruit Field||8||132||3.50||2.06|
|Large Fruit Field||11.2||184||3.57||1.44|
|Small Ore Mine||4.8||128||3.33|
|Medium Ore Mine||8||192||6|
|Large Ore Mine||11.2||208||11.43|
|Small Ore Mine Underground||6.4||160||5|
|Large Ore Mine Underground||9.6||224||6.67|
|Seabed Mining Vessel||8.8||204||6.81|
|Small Oil Pump||4.8||168||5|
|Large Oil Pump||8||272||6|
|Small Oil Drilling Rig||6.4||216||6.25|
|Large Oil Drilling Rig||9.6||304||8.33|
|Offshore Oil Platform||11.2||288||14.29|
All values are for original production rates. This is changed as zones level up and with worker's barracks in the zone. Input and output are in tons per week. Profit takes into account upkeep but not water nor electricity. Many processors create mass by taking in a smaller amount of raw materials to make a larger amount of processed materials.
|Building||Raw Forest Products||Planed Timber||Profit/week|
|Engineered Wood Plant||-4.8||6.4||576|
|Building||Raw Forest Products||Paper||Profit/week|
|Biomass Pellet Plant||-3.2||3.2||176|
|Small Animal Pasture||-3.2||2.4||256|
|Large Animal Pasture||-6.4||5.6||552|
|Ore Grinding Mill||-3.2||3.2||432|
|Rotary Kiln Plant||-4.8||6.4||976|
|Glass Manufacturing Plant||-3.2||3.2||368|
|Oil Sludge Pyrolysis Plant||-3.2||4||832|
|Waste Oil Refining Plant||-4.8||8||1,808|
|Naphtha Cracker Plant||-4.8||8||1,728|
Unique Factory Rates
All values are for 100% production rates and in tons. Weekly Profit includes cost of upkeep but not cost of water and electricity. Goods are a shared output by all factories and the other materials are all inputs.
|Building||Planed Timber||Paper||Crops||Animal Products||Flour||Metal||Glass||Petroleum||Plastic||Goods||Weekly Profit||Profit/inputs|
|Industrial Steel Plant||-6.4||6.4||4,160||634.375|
|Household Plastic Factory||-3.2||-3.2||3.2||800||125|
|Soft Paper Factory||-3.2||-3.2||-3.2||-3.2||7.68||4,256||332.5|
|Modular House Factory||-3.2||-3.2||-3.2||-3.2||10.88||6,640||518.75|
Trucks can transport 8 tons of any material at a time. Trucks are always owned by the building exporting the materials and return to that building. If a truck takes the materials out of the city it shows up as revenue on the districts information popup and under the industries tab in the budget. If the truck takes the materials to a train, ship, or plane cargo exporter and it is then shipped from the city it shows up as revenue for the appropriate transport option on the mass transit tab in the budget. This means that a zone may show that it is losing you money in its information tab when it isn't. Materials transported from building to building do not earn you any money. Only materials shipped from the city bring revenue.
Raw materials can be imported from other cities but processed materials must be made locally. This means drilling and mining processors can still work once reserves are depleted, but with slightly lower profits since they must pay to import the oil and ores.
A building producing materials checks for exporting materials once it gets 8 tons in it's storage. It first checks if there are consumers that need the material at that exact moment, then for storage buildings that can take it, then for exporting the materials. Storage can fill up if trucks can not return to the building quickly enough and this most often happens when exporting materials to another city. Mass transit exports can help with this but are not always used. It is possible to force mass transit to be used by cutting off road access and forcing exports to go through a mass transit station. This will shorten the distance that your trucks must travel, allowing them to return quicker and ship more, but will hide the zone's profit.
A building consuming materials checks for importing materials once it gets 8 tons free in it's storage and again if it gets to 16 tons free. Since the base storage is eight more than what is consumed in two weeks, if shipments can consistently arrive in less than 2 weeks a building can continuously produce. This travel time buffer can be increased for processors with maintenance buildings that increase storage capacity. For unique factories it can be increased to as much as 4 weeks by decreasing production rate. There is no way to increase a unique factories storage. The game does not always request materials from the closest source so to keep things flowing consistently the furthest possible source of consumed materials needs to be within that travel time.