Power Guide: Generators, Solar, Accumulators & Grids

Power is the core system that supplies energy to every machine and structure in Factorio; understanding generation, storage, distribution, and management is essential for stable growth and scaling.

Units and basics

• Energy is measured in joules (J). Power (rate of energy) is measured in watts (W) where 1 W = 1 J/s. Common in-game units are kilowatts (kW) and megawatts (MW).
• Many entities list power as kW or MW (for example: a lamp uses 5 kW, a radar uses 300 kW, a steam engine outputs 900 kW at full load).
• Steam carries stored energy proportional to temperature above ambient: steam energy = 200 J per unit per °C (ambient is treated as 15°C). Boiler steam is 165°C; heat-exchanger/chemical-produced steam is 500°C. Steam does not lose heat in pipes or tanks and steam engines/turbines convert that stored energy at 100% efficiency.

Generation methods

1. Steam (fuel + water)

   • Classic setup: Offshore pump → boilers → steam engines.
   • Boiler energy input and steam engine consumption determine ratios: one boiler produces enough steam for two steam engines at full load (boiler consumes 1.8 MW of fuel energy; each steam engine uses 0.9 MW).
   • For large-scale high-temperature generation, heat exchangers producing 500°C steam feed steam turbines: one steam turbine consumes 60 units/s of 500°C steam and outputs 5.82 MW.
   • Steam calculations: (temperature difference) × 0.2 kJ × steam units/s yields power. Example: a turbine at 500°C: (500 − 15) × 0.2 kJ × 60 = 5820 kJ/s = 5.82 MW.
   • Typical placement ratios (classic steam engine approach): Offshore pump : Boilers : Steam engines = 1 : 200 : 400 (based on water throughput and boiler/engine consumption).
   • Boilers use fuel; different fuels change burn rate and density (e.g., coal consumption per boiler ≈ 0.45 coal/s for standard fuel).

2. Solar

   • Solar panels generate power only during daytime. On Nauvis a normal-quality solar panel averages 42 kW over a day.
   • Common practical rules: roughly 25 solar panels to 21 accumulators to supply ~1 MW continuously (rule-of-thumb; exact ratios vary with panel/accumulator quality and planet).
   • Use accumulators or operational scheduling to run at night.

3. Turbines and high-temperature methods

   • Steam turbines are used with 500°C steam (from heat exchangers or acid neutralisation) for high-density generation.
   • On special surfaces (e.g., Vulcanus) solar output and other generation methods may behave differently (Vulcanus solar gives 4× Nauvis output; acid neutralization can create 500°C steam without water).

4. Other generators

   • The game includes other advanced generation (nuclear fusion/other DLC/planet-specific mechanics). Those follow the same power-distribution rules: producers throttle if network demand is lower than supply to avoid waste.

Storage

• Accumulators store electrical energy. They have lower delivery priority than other network consumers, so they charge only from surplus and can be used to isolate networks when shared between multiple networks (connect accumulators to both networks via separate electric poles but avoid direct pole-to-pole connection between the networks).
• Storage tanks can act as "energy tanks" by storing steam: a storage tank holds 25,000 units of fluid.
  • At 165°C (boiler steam) a full tank stores 750 MJ.
  • At 500°C a full tank stores about 2.425 GJ — enough to run one steam turbine (5.82 MW) for ~417 seconds.
• Use accumulators for electrical buffering (fast response) and steam tanks when using steam turbines/engines as a buffer for mid-term shifts (day/night solar cycles, turret bursts).

Distribution and networks

• Electric poles connect producers and consumers into an electrical network. If two networks are connected by any pole connection, they are the same network.
• Power switches provide a controllable break between two sides of wiring. They allow toggling which side is connected but have no effect if other connections between the two sides exist. Use shift-click on poles to clear wires when isolating networks.
• Copper wire (circuit wires) are separate and used to connect entities to the circuit network for logic/control; red/green wires transmit numeric signals (32-bit signed integers).

Management techniques

• Match generation technology to needs:
  • Early game: boilers + steam engines are simple, cheap and fuel-flexible.
  • Mid/late game: solar + accumulators provide low-maintenance, pollution-free base power; turbines with 500°C steam give high density power when space-fuel constraints exist.
• Use accumulators to smooth solar output and to provide night-time power. Optimal solar:accumulator ratios depend on panel/accumulator quality and planet — use the in-game numbers or the rule-of-thumb above for quick design.
• Beacons and modules
  • Beacons can massively boost production throughput but consume 480 kW each and must be powered continuously. They are most efficient when placed in arrays that cover many module-capable machines (row-array designs reduce beacons-per-machine while keeping tiling simple).
  • Avoid beacons for rarely-run machines or non-module-compatible entities. Use a power switch to cut beacon networks when machines are idle to stop wasting energy.
• Circuit control: connect power switches and generator controls to the circuit network to automatically enable/disable power islands (e.g., disable parts of the base at night to conserve accumulator charge).
• Isolation patterns: accumulate energy on a shared set of accumulators bridged between two networks to let one network charge them and another draw from them while keeping pole networks otherwise separated.

Practical numbers and layouts

• Steam engine (classic): 900 kW per engine; 1 boiler → 2 steam engines.
• Steam turbine: 5.82 MW using 60 units/s at 500°C.
• Storage tank fluid capacity: 25,000 units; energy stored depends on steam temperature (750 MJ at 165°C, ~2.425 GJ at 500°C).
• Solar panel average (Nauvis): 42 kW; common practical design uses ~25 panels + 21 accumulators per ~1 MW target.
• Beacons consume 480 kW each.

Tips and common patterns

• Early to mid game: build coastal steam arrays spaced for belt/pump water supply; keep fuel supply belts/chasms well-fed and use stackable boilers/engines in compact grids.
• Transition to solar gradually: power critical loads and charge accumulators during the day, then move non-critical or high-pollution production to daytime-only networks if needed.
• For dense production boost, use beacon row arrays (surround rows of machines with beacon rows) to maximize module coverage per beacon while minimizing power overhead.
• Use storage tanks when designing turbine-based systems or when you want a large burst of power without adding massive accumulator farms.
• Monitor networks with radars/lamps and control via circuit network signals to automate load shedding and islanding.

Understanding these generation, storage, and distribution building blocks — with the concrete numbers above for key machines — lets you design power systems that scale from starter bases to megabases without brownouts or wasted resources.