Power

Power is electrical energy that powers the operation of certain appliances, including workbenches, lights, temperature control devices, automated defenses, and more. Access to power is crucial to survival, especially in late game. The success of a colony often relies upon a fault-tolerant power grid with a reliable power flow that ensures that your appliances are working at all times, especially in emergencies.

Power generators

Chemfuel powered generator

The chemfuel powered generator produces power from chemfuel. The generator is an exact analog to the wood-fired generator, only the type of fuel is different.

Wood-fired generator

The wood-fired generator is identical to the chemfuel generator, except that it is fueled by wood and is slightly cheaper to construct. Requires no research for New Arrivals. Unlocked by researching Electricity for Tribal starts.

Geothermal generator

The geothermal generator is a power generator that can be built on top of a steam geyser to convert natural heat into electrical power, providing a constant 3600W. Steam geysers are randomly generated per map, sometimes close to each other, others scattered towards the edges or center. Colonies are often seen built in their proximity from early days for future benefit. Requires researching Geothermal power

Solar generator

A solar generator provides up to 1700W of power from sunlight. It has much smaller space requirements than a wind turbine but provides no power at night or during an eclipse. It can be placed in a wind turbine's exclusion zone with no effect on the turbine. Solar generators may be protected by surrounding them with walls, but they must stay unroofed to operate. Requires no research for New Arrivals. Solar power must be researched separately by Tribal starts.

Wind turbine

A wind turbine produces a variable amount of power up to 3450W, based on the current wind speed (for wind conditions see Weather). Requires no research for New Arrivals. Unlocked by researching Electricity for Tribal starts.

Watermill generator

A watermill generator provides power from a moving river, providing a constant 1100W of power. It is relatively cheap and requires no upkeep, but is also fairly large and cannot be placed too closely to another without degrading performance. Requires research.

Ship reactor

Although it is a ship part and not listed in the Power menu, the ship reactor is perfectly usable as a power generator. It provides 1000W of power, with no need for fuel or other maintenance; it does not generate any heat. It is normally only built as part of the space ship to win the game, and must be powered up to become operational for the ship, which triggers a 15-day long enemy invasion event. Requires research.

Vanometric power cell

Similar to the ship reactor, the vanometric power cell provides a consistent 1000W of power at all times with no upkeep or restrictions. It has a small 1x2 footprint and can be moved freely. The catch is that these power cells are very rare; they cannot be manufactured or purchased, only received as a quest reward. With their comparatively low output, there is no reliable way to acquire enough to satisfy more than a small fraction of a normal colony's power budget, but they are a convenient way of powering high-priority or off-grid equipment.

Unstable power cell

Effectively a smaller, less powerful and significantly more explosive vanometric power cell from the Royalty DLC. It can only be captured from Mechanoid clusters. It provides 400W with no need for fuel, in 1x1 footprint that can be moved around freely. While more common than the vanometric power cell, its fragility and explosive tendencies can make it hard to capture from clusters and care must be taken to shield it from damage when in use. It also only produces a relatively small amount of power, so like the vanometric power cell, it is most useful for off-grid or high priority items rather than supplementing the main power grid.

Power generator summary

Type	Cost	Size	Max Output (Watts)	Placement
Solar	100 3	4x4	1700	In sunlight
Wind turbine	100 2	5x2	3450	In open ground
Watermill generator	280 80 3	5x6	1100	On riverbanks
Chemfuel generator	100 3	2x2	1000	Anywhere
Wood-fired generator	100 2	2x2	1000	Anywhere
Geothermal	400 8	6x6	3600	On geysers
Ship reactor	300 500 150 25	6x7	1000	Outside (can roof over afterwards)
Vanometric power cell	N/A	1x2	1000	Anywhere
Unstable power cell	N/A	1x1	400	Anywhere

Power transfers

Power conduit

A power conduit transmits power from generators or batteries to appliances up to six squares away. Conduit doesn't block the placement of other structures and isn't blocked by them, so conduit can be placed wherever it's needed, even in walls, except unsmoothed mountain rock and mineral ores.

Waterproof conduit

A Waterproof conduit transmits power from generators or batteries to appliances up to six squares away. Waterproof Conduit can only be built on water.

(note: the image for the waterproof conduit is actually an image of the power conduit, RimWorld Wiki is currently lacking an image for the conduit. The conduit is actually tinted blue.)

Power switch

A power switch is used to toggle power of the conduit lines connected to it. It provides an efficient way to control power to several appliances all at once, such as a large array of improvised turrets.

The 'Toggle power' button is used to request the switch to be flipped. A colonist with the 'flick' job type will flip the switch.

To construct a switchable circuit simply place the power switch along a line of conduit between the power source and the appliances. While one of the switch's connectors must connect to conduit to a power source, any or all of the three remaining connectors can be used to create branches. A switch can be placed directly adjacent to a battery or other power source, but the player will probably find it desirable to place the switch close to the appliances it's meant to control. Appliances won't connect directly to a switch, they only connect to conduit.

When the power switch is on the inspect pane displays 'Power: On', and the center of the power switch shows a pale circle.

When the power switch is designated to turn off, the 'Toggle power' button displays a red X.

When the power switch is off , the inspect pane displays 'Power: Off', and the center of the power switch is dark.

When the power switch is designated to turn on, the 'Toggle power' button displays a green check mark.

Power storage

Batteries

The battery is an electric device that can even out the power supply on an electric grid. It will provide enough power to compensate for any deficit, while charge remains. If there is surplus power, the battery will recharge, but only at 50% efficiency (half the energy is lost). The charge capacity is 600 Watt-days. Batteries self-discharge at a rate of 5 W, even while disconnected, and need to be operated under a roof to keep them dry (rain or snowfall will quickly cause an explosion).

Usage

Batteries are built, moved and stored like other kinds of movable furniture. They will keep their charge while stored ("minified") or disconnected, only discharging at the normal rate of 5 W (self-discharge).

With regards to power production, they behave like the other electric buildings in the game. All power consumers can connect to batteries in the same way as to other power sources: within a 5-tile radius, a device can directly connect to a battery (or array of batteries), without power conduits in between.

In order to charge a battery, it has to be directly connected to a power grid with excess power. It is not possible to connect to batteries "through" power consumers (this is because consumers can not be connected to more than one power grid at the same time).

Just like the other power producing buildings, a battery acts as a power conduit on the 2 tiles it covers.

Installed batteries can not be switched off manually. As long as at least one consumer is connected, the battery will provide power during a deficit, and also be vulnerable to the short-circuit event.

Installed batteries need to be kept dry. If outdoors, a roof has to be built over the tiles occupied by the battery. If a battery becomes wet (either due to rain or snowfall), there is a very high chance of a short circuit, causing an explosion and fire (probably spreading to adjacent batteries and connected devices). At least the rain will usually extinguish the fire...

Damage to a battery does not change its other properties and does not cause discharge (eg. a 1 hitpoint battery has the same capacity and wattage as a 100 hitpoint battery).

Batteries as power supplies

Consumers can connect to batteries directly, up to a distance of 5 tiles away, by using the reconnect action on the consumer until it is connected to the battery.

The battery can also be connected to a power grid like any other power generator. Simply placing the battery next to a generator, power conduit, switch or another battery will connect it to the respective power grid.

As a power supply, the battery behaves just like any other power source in the game (eg. generators or solar panels), but each battery will deliver an unlimited amount of power. This means that any wattage can be delivered until the battery is completely discharged. It makes the battery not only convenient as buffers for wind turbines and solar panels, but also to cover arbitrary spikes in power usage, usually caused by turret arrays and other heavy power consumers that are only brought on-line sporadically.

The power output of a battery is theoretically unlimited. Even a huge colony that demands, say, 30,000 W of power can be powered by a single battery (but only for about 1 in-game hour if the battery is fully charged). Adding more batteries is only necessary to lengthen the time span.

If more than one battery is on the same power grid, all batteries with remaining charge will share the power load evenly.

The maximum amount of energy provided per battery is 600 Wd (watt-days) for a fully charged battery. Eg. if exactly 595 W were drawn, a single battery would last exactly 1 in-game day (taking into account the 5 W of self-discharge). If only 295 W are drawn, it lasts for 2 days, etc. Since maximum power draw is unlimited it is – theoretically – possible to empty a full battery in 1 tick of game time (instantly).

A disconnected battery will discharge at a rate of 5 W. This means that a fully charged battery can be stored for 120 days (2 in-game years) until depleted.

Charging

Batteries charge automatically while connected to a power grid with excess power. Selecting the battery will show the current charge status in the information window.

The power used for charging is unlimited, ie. charging batteries will always draw all power that is not used by other consumers, so they never cause a power deficiency on the grid. All batteries on a grid will share charging power fairly.

Only half the power used for charging is stored as energy, ie. the charge efficiency is 50%. In other words, to fully charge an empty battery, 1200 Wd of energy must be provided (in addition to a constant 5 W to cover the self-discharge), but only 600 Wd will get stored.

As an example, connecting an empty battery to a power grid with exactly 1205 W of available power will charge it to full in exactly 1 in-game day. If more power was available, charging would complete more quickly. 5 W of charging power would keep the battery at exactly the present charge level, merely nullifying the self-discharge.

In practice, the self-discharge can usually be ignored.

Constructing, moving and storing

Batteries behave exactly like other furniture items in the game: they have to be constructed on solid terrain, using the construction skill. It takes 14 work units to build, and can be done even at construction level 0.

After construction, they can be uninstalled like furniture, and then moved to storage, taken to a character's inventory or on a caravan. Uninstalling and reinstalling does not cause additional charge loss, beyond the 5 W of self-discharge that always applies.

It is possible to take charged batteries on caravans as a power source for camps and newly founded colonies.

Batteries that are not installed can be stored in the open, also in rain or snowfall, as they can not short circuit. Like other furniture, they are not subject to decay.

Hazards

Batteries are very likely to explode in rain and snowfall. This can be completely avoided by keeping installed batteries under a roof; keeping them indoors is not necessary. The resulting explosion will not cause any discharge, but it will heavily damage the battery, and possibly surrounding structures as well, also causing a fire.

Batteries make the short circuit event ("Zzztt...") more dangerous: all affected batteries will instantly discharge, causing an explosion in addition to the fire that is normally caused by the event. The more batteries are connected, the larger the explosion. However: "Zzztt" happens to conduits, not batteries. A short circuit can still happen in a zero-battery power grid, but will only cause a one-tile fire and no explosion. Empty batteries will not affect the event.

It is not the batteries that explode, but a random area around the affected power-conduit. This could be right next to a battery, or a long distance away from it.

The short circuit event can be completely avoided if there are no power conduits connected to the battery. You can disconnect the batteries from the main power grid with a power switch. The switch needs to be placed directly next to the battery array, separating the power conduits on the main grid from the batteries. The batteries are only protected if the switch is turned off, separating the connection. This makes the solution impractical for batteries that need to be always online.

Batteries connect directly to the wind turbine and the attached coolers, with no conduits. This power grid will only "Zzztt" if the batteries get rained on.

It is also possible to avoid building any power conduits at all. This is only feasible for small, self-contained installations. The batteries themselves, as well as other power generating buildings, have built-in power conduits, but these are immune to short circuits. Because appliances can directly connect to batteries and generators, you can construct conduit-free power grids with some careful planning.

If the above measures are impractical, firefoam poppers should be installed where an explosion would cause a lot of damage, such as inside a hydroponics facility or a storage area.

Battery performance is not affected by temperature. Somewhat contrary to the in-game description, the battery is not more susceptible to heat than other, comparable flammable structures. Even the most extreme heat waves will not make a battery explode or catch fire. It is therefore not necessary to keep batteries climatized.

Strategy

Batteries are useful in most colonies, even if the colony does not rely on unstable power sources like solar panels and wind turbines.

If only renewable energy is used, at least one battery is mandatory, because sufficient power supply can never be guaranteed. Solar panels produce no power during the night and during an eclipse, and wind turbines are completely unreliable. If the colony has no other backup power source, it is highly recommended to keep some additional batteries behind a power switch on a separate network (see Hazards above), so they can be brought online in the case of a short circuit event.

Alternatively, some batteries can also be stored in a warehouse, and then placed down anywhere on the power grid on demand. This makes switches unnecessary.

Batteries can also be used to make fueled generators more economical. These generators provide constant power, but they also burn their fuel at a constant rate – no matter how much power is actually used. If you connect some batteries, you can at least catch half of the otherwise wasted energy, and then disable the generator until the batteries run dry. This will save 100% of the fuel for the time the generator is offline. This is especially helpful in the early game, where you might not even have enough power draw to fully load a single generator, and fuel will be usually scarce as well.

The energy stored by even a single battery is very high. 600 Wd are enough to power, for example, three coolers at full power draw for an entire day, with no other source of power available. Therefore, building a lot of batteries ("just to be safe") is not necessary, or even harmful. Unless you take complex and expensive measures to avoid the short circuit event, having too many batteries online is a liability. Examine closely how much energy storage you need, and do not build more than that.

When you calculate the battery capacity that is necessary when using renewable energy, keep in mind that charge efficiency is only 50%. That is, only half of any excess energy will be effectively usable. This is particularly relevant when planning a greenhouse setup, of hydroponics basins and a sun lamp. The sun lamp will draw 2900 W during the day, and 0 W during the night, for an average demand of 1450 W. However, it is not sufficient to generate only 1450 W at all times, hoping that a 3-battery array will even out the difference in power draw. This is because during the night, only half of the extra 1450 W will effectively charge the batteries, storing 8,700 Wh of energy (~360 Wd). This will only be enough to power the sun-lamp for 6 hours during the day. For the remaining 6 hours, the missing 1450 W will have to be provided by other means (usually a solar panel). Simply adding more batteries will not change this. Two batteries will provide enough buffering in this scenario.

The example setup, including 24 hydroponics basins, can be fully powered by one geothermal generator and a solar panel, connected to a single buffer battery.

Even in colonies that do not use wind or solar energy, batteries are useful to cover spikes in power usage, usually caused by turret arrays and devices like crematoriums, smelters and mineral scanners that are only brought online intermittently. A battery can cover arbitrarily high power needs, the size of the array only changes for how long that is possible.

As an example, an array of 20 mini-turrets and 4 autocannon turrets draws 3200 W of power. Instead of building another geothermal generator that would cover this, even a single charged battery can power this entire setup for more than 4 in-game hours. An array of 5 batteries can power the defenses for an entire in-game day. The battery array should be isolated with two power switches from the security grid and main power grid. This makes it then also very easy to power the entire setup with a single switch, as well as keep the batteries safe from the short circuit event.

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Architect

Power: Power conduit (Waterproof) • Power switch • Wood-fired generator • Chemfuel powered generator • Wind turbine • Watermill generator
(research): Geothermal generator • Solar generator • Battery
(uncraftable): Vanometric power cell • Unstable power cell

Appliances

Appliances are structures or buildings that require power but don't transmit it. Most appliances can connect automatically if placed up to six squares away from a conduit, generator or battery. When connected to the power grid, it can take a few moments before an appliance turns on.

Managing appliances

Reconnect: Click to force an appliance to reconnect to a conduit line or power source. This can also be used to change which power source an appliance is connected to if there is more than one in range.
Designate toggle power: Click to mark an appliance to be turned on (✔) or off (X) by a colonist set to flick.


Reconnect


Designate toggle power

Appliances summary

Appliance	Power consumption (in Watts)
Autodoor	50
Electric tailor bench	120
Electric smithy	210
Machining table	350
Electric smelter	700
Electric crematorium	250
Hi-tech research bench	250
Multi-analyzer	200
Fabrication bench	250
Nutrient paste dispenser	200
Standing lamp	75
Sun lamp	2900 during day only
Hydroponics basin	70
Biofuel refinery	170
Infinite chemreactor	300
Vitals monitor	80
Comms console	200
Ground-penetrating scanner	700
Long-range mineral scanner	700
Electric stove	350
Heater	175
Cooler	200
Mini-turret	80
Tube television	200
Flatscreen television	330
Megascreen television	450

Version history

0.0.245 - Electrical devices now short-circuit and cause fires if left out in the rain while running.