Electricity

Electricity is a system and resource in Space Engineers that is used to power most devices. It is created using a large or small reactor, or by using a Solar Panel. It can be stored in a Battery. Any device that has a direct block connection to a reactor will be powered by a reactor; that is, if a reactor is on a ship, all devices attached to that ship should receive power granted there is enough power to receive. Electricity can pass through rotor blocks, pistons, and locked connectors (incl. small-to-large connections), but not landing gear. Most blocks have off switches if you want to save electricity temporarily.

Electricity fundamentals & Terminology

In Space Engineers, electricity is based around several concepts. When referring to consumption or demand, a Watt of energy demand will consume 1 watt over 1 second. Watts come in various unit conversions from KW to MW, as seen in the table. When referring to energy stored or energy needed over time, a Watt-hour (W-h) is typically used to represent this amount over an hour (3600 seconds). This is typically used to refer to stored energy in a charged battery or to fuel like uranium ingots. Reactors are the main source of reliable electricity, and they require Uranium Ingots as fuel.

1 kg of refined uranium ingots converts to 1 MW-h of power, that is a reactor that needs to supply 1 MW per second to ship or station will consume all of its uranium in 1 hour. If the reactor needs to supply 2 MW per second, it will consume 1 kg of uranium in half the time and so on. For example, a large block Small Reactor generating electricity at maximum capacity 15 MW to supply a large ship's total electrical needs (such as refineries, thrusters at full capacity, etc), will consume 1 kg of uranium in 4 minutes. While a large block Large Reactor will consume 1 kg of uranium ingots in as little as 12 seconds, at it's full output of 300 MW per second. Consumption of Uranium is solely decided by your current energy demand. There is no difference in efficiency between large and small reactors per uranium ingot, so a large reactor doesn't use uranium or extract any more energy out of a uranium ingot than any small one would. It also makes no difference how many reactors you have online, reactors that are not needed will not draw any unnecessary power or use any uranium within them until required.

A Battery is special it doesn't general electricity it merely stores it for later use, its wise to combine renewable electrical generation from solar panels with batteries and never use reactors as the battery is only 80% efficient. That is while it will draw 4 MW per second and store 3.00 MW-h (for large blocks), the battery will actually end up demanding/using 3.75 MW-h from electrical sources - 750 KW-h will be wasted. A Large Ship battery continuously at full output 12 MW, at maximum charge 3.00 MW-h will be completely depleted in 15 Minutes.

Conversion Table	Watt (W)	Kilo-Watt (KW)	Mega-Watt (MW)
Mega-Watt (MW)	1'000'000 W	1'000 KW	1 MW
Kilo-Watt (KW)	1'000 W	1 KW	0.001 MW
Watt (W)	1 W	0.001 KW	0.000001 MW

Energy sources

Maximum output for Electricity Sources:

Energy Source		Block size	Dimensions [size in m3]	Maximum Output [KW]	Mass [kg]	Mass Efficiency [KW/Kg]	Energy Density [KW/m3]
	Large Reactor	Large	3x3x3 [421.875 m3]	300'000	73795	4.065	711.11
		Small	3x3x3 [3.375 m3]	14'750	4793	3.845	960
	Small Reactor	Large	1x1x1 [15.625 m3]	15'000	3901	3.077	4370.37
		Small	1x1x1 [0.125m3]	500	278	1.799	4000
	Solar Panel	Large	2x4x1 [125 m3]	120*	441.4	0.272	0.96
		Small	5x10x1 [6.25m3]	30*	159.2	0.188	4.8
	Battery	Large	1x1x1 [15.625 m3]	12'000	4845	2.477	768
		Small	3x2x3 [2.25m3]	4'320	1040.4	4.152	1920

(*) Solar Panels have a maximum output depending on their angle to the sun and the amount of actually lit surface. Given values are the maximum achievable output with perfect conditions, therefore efficiency and output may vary.

Large Reactor vs Small Reactor

Comparing them directly especially, the small reactors provide far more energy for the space they take up; Needing only 20 Small Reactors to equal the output of a Large Reactor with Two-Thirds of the space used. Despite this the large reactor offers greater economies of scale, require less Conveyor complexity and in general more useful in a variety of important applications especially as Powerplants for Large Ships being both lighter and requiring less resources. Making Large Reactors ideal for ships that can take advantage of their lessened mass and accelerate or decelerate more easily and therefore use less Uranium Ingots. Small Reactors are therefore ideal for stations that do not need to move, situations where physical space is precious or relatively light power needs that would not require a larger more expensive reactor. For example, a large reactor only needs 40 Metal Grids while a small reactor needs 4 Metal Grids at approximately 10 Small Reactors (150 MW) you would start to see economy of scale benefits clearly when using the large reactor. Between them however, they use Uranium Ingots equally as efficiently neither one will manage to extract more energy than they would otherwise have to.

Power Usage

Thruster

Thruster type		Block type		Minimum Power [KW]	Maximum Power [KW]
	Small		Small	0.002	201
	Large		Small	0.002	2'400
	Small		Large	0.002	3'360
	Large		Large	0.002	33'600

Production (Individual Usage)

Machine		Idle [KW]	Operational [KW]
	Projector	0.100	0.198
	Arc Furnace	0.999	330.000
	Assembler	0.999	560.000
	Refinery	0.999	560.000

Weaponry and tools

Device		Small Ship [KW]	Large Ship [KW]
	Drill	2	2
	Welder	2	2
	Grinder	2	2
	Gatling Turret	N/A	2
	Missile Turret	N/A	2
	Interior Turret	N/A	2
	Reloadable Rocket Launcher	0.2	N/A
	Gatling Gun	0.2	N/A

Communication

Device		Small Ship [KW]	Large Ship [KW]
	Beacon	0 - 10	0 - 10
	Antenna	0 - 20	0 - 200
	Laser Antenna	181**	577**

(**) The maximum power usage of laser antenna include both beaming and rotating at once. Beaming alone would be 180 for Small and 576 For large.

Other device power usages

Device		Small Ship [KW]	Large Ship [KW]
	Gravity Generator	N/A	0 - 567.13***
	Spherical Gravity Generator	N/A	0 - 44800***
	Artificial Mass	25	600
	Interior Light	N/A	0.06
	Spotlight	0.200	1
	Medical Room	N/A	2
	Door	N/A	0.031
	Gyroscope	0.001	0.03
	Ore Detector	2	2
	LCD Panel	0.1	0.1
	Wide LCD Panel	0.2	0.2
	Button Panel	0.1	0.1
	Rotor	0.2	2
	Advanced Rotor	0.2	2
	Piston Base	0.2	2
	Collector	2	2
	Connector	0.05	5
	Camera	0.03	0.03
	Sensor	0 - 30	0 - 30
	Remote Control	10	10
	Programmable Block	0.5	0.5
	Sound Block	0.2	0.2

(***) The power cost of Gravity Generator is directly proportional to the field size and acceleration (absolute value, so 1G consumes the same as -1G).