Power production

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Electricity and Liquids have many interactions and can be incredibly difficult to learn- this page documents several important components of electricity production. It is divided up into different topics that are important to keep in mind.

Steam power optimal ratios

0.14 and earlier versions

Each Steam engine needs roughly 1.31 Boilers when running at full capacity.

One offshore pump can satisfy 14 Boilers and 10 steam engines. 13 boilers will work, but this tends to have issues recovering after coal shortages or other accidents.

Each 10 steam engines need 2.5 electric mining drills when running at full capacity. This is calculated as follows: mining drills produce 0.525 coal/second. Coal contains 8 MJ of energy, and boilers are 50% efficient, so every mining drill generates 2.1 MJ/second in the boilers. To reach 5.1 MW you need 5.1/2.1 = about 2.5 mining drills.

0.15 and later versions

With version 0.15 each Steam engine needs exactly 0.5 Boilers when running at full capacity. One offshore pump can supply 20 boilers and 40 steam engines.

See also

Solar Panels/Accumulators

Optimal ratio

The optimal ratio is 0.84 (21:25) accumulators per solar panel, and 23.8 solar panels per megawatt required by your factory (this ratio accounts for solar panels needed to charge the accumulators). This means that you need 1.428 MW of production (of solar panels) and 100MJ of storage to provide 1 MW of power over one day-night cycle.

A "close enough" ratio is 20:24:1 accumulators to solar panels to megawatts required (for example, a factory requiring 10 MW can be approximately entirely powered, day and night, by 200 accumulators and 240 solar panels - this approximation differs from optimal only in that it calls for 2 extra solar panels, which is negligible).

This is taken from Accumulator / Solar Panel Ratio (which calculates this in an impressive mathematical way!) and another post in that thread (which calculates the solar panel to megawatt ratio in a different way).

A small 9x9 blueprint demonstrating the 20:24 "close enough" ratio above.
A medium 28x28 blueprint with a nearly optimal ratio.
A large 48x48 blueprint with a nearly optimal ratio. It also contains a roboport in the center to repair itself and automatically construct adjacent blueprint copies.


The optimal ratio of accumulators per solar panel relies on many values in the game. These include the power generation of a solar panel, the energy storage of an accumulator, the length of a day, and the length of a night. There are also times between day and night called dusk and dawn which complicate the calculations. In vanilla factorio, without mods which change any of these values, the optimal ratio will be the same. This ratio is

Accumulators / Solar_panels =
    (day + dawn) * (night + dawn * (day + dawn) / game_day) / game_day
    * Solar_power / Accumulator_energy

which, given the default time lengths of: day = 17500/60 s; dawn or dusk = 5000/60 s; night = 2500/60 s, and the default: Solar_power = 60 kW; Accumulator_energy = 5 MJ = 5000 kJ, gives the optimal ratio of 0.84 accumulators per solar panel. If the player uses mods which change the power generation of solar panels, or the energy storage of accumulators, but not the length of days, a simplified version of this equation can be used.

Accumulators / Solar_panels = 70 s * Solar_power / Accumulator_energy

This equation could also be used to remember the vanilla optimal ratio given its simplicity. If the only effect the mod has on the game is it changes the total length of one day, without changing the ratio of dusk : day : dawn : night, then the equation can be simplified as

Accumulators / Solar_panels = 0.002016 /s * game_day 

where game_day is the number of seconds in the game day which is 25000/60 s by default.

See also

Ensuring enough energy is produced

Try this checklist before you completely revamp your power source. You may also use this to rectify negative feedback loops.

  • Did you connect the steam engine to the Electric network? If not, a small yellow triangle will flash. To fix, Add some power poles near the steam engines that go to machines needing that power. Any size will work.
  • Is steam able to reach all steam engines?
  • Do your pipes have water? Look at the glass windows in the pipes, hover over the pipes! Place some pipes or a tank at the end to see if there is really water coming through. If not, ensure all pipes or underground pipes are connected together.
  • Do you have enough Boilers? The steam temperature should reach 165 degrees.

See also the applied power math tutorial to answer the question how much coal do I need?

Energy Storage

See Basic accumulator.

Energy is available (or storable) from/to:

See Units#Power for info on energy units.

Storing steam in tanks

Since 0.15.0, a Storage tank filled with Heat exchanger 500°C Steam stores around 2.4GJ; a Storage tank filled with Boiler 165°C Steam stores 750MJ. Read more about this: Yet another "Steam engine backup" solution (simple&low tech).

There are several advantages to storing energy in storage tanks vs. storing it in an accumulator:

  • You don't need to produce electrical energy first.
  • The energy density per tile is much higher than it is with batteries.
  • You won't get sudden blackouts when you're out of power. Instead, power goes out gradually as pressure drops.

See also

Types of energy

In factorio, there are two types of energy, Burner, and Electric.


Burner energy is energy obtained from burning Fuel in a machine, such as a Burner Mining Drill, or Car.


Electricity is produced by generators, or energy storages when draining. It is an intangible energy that flows through power poles.

Electricity is the only way to transport energy over long distances quickly. Electricity itself doesn't pollute, pollution comes either from burning fuel or consuming electricity. Different amounts of energy consumption yield differing amounts of pollution.

Common sources of electric power are steam engines, Basic accumulators, or solar panels.

The electric priority

Electricity is provided on a priority basis. When a draw for power is created, power will come from these machines, in order. This means:

  • Solar panel - These will provide power first, if they do not satisfy the draw...
  • Steam engine and Steam turbine - Steam engines and turbines will start functioning, if the draw is still not satisfied...
  • Basic accumulator - Lastly, the energy in accumulators will be consumed.

This works in the opposite way as well: The accumulators are only filled if the demand of all other consumers are fulfilled.

Transmitting energy


Power poles are used to transmit energy. See Small electric pole, Medium electric pole, and Big electric pole for more info.

Autoplacing poles

It is possible to automatically place poles at maximum distance apart. To do this, left click and hold, then move the mouse or walk. The poles will automatically be placed the optimal distance apart.

This works from a car or train as well, which enables placing the electric poles very quickly over long distances.

Cables (and Wires)

When you place an electric pole it will automatically cable itself to other poles in range. These cables are "free" and do not consume any copper cable. If you remove these cables, you can regenerate them by removing and rebuilding the pole.

You generally don't need to manually add copper wires, because any pole in range will be connected automatically by the free wires. Placing copper wire is only useful when precise control is needed, such as hooking up a power switch between two networks.

Removing cables

Remove all cables from an electric pole by shift-left-clicking it. The pole will become an independent electric network. You can reconnect it to other poles by placing cables manually.

Add cables or wires

A cable or wire can be added by holding Copper cable in your hand, left-clicking the base of one pole, then left-clicking the base of another. Use copper cable for the electric network, or red/green wires for the circuit networks. Note that the wire item is consumed when you make the connection; you will not get it back if you remove the pole's wires, or if you remove the pole itself.