Redstone Flux

Redstone Flux (RF) is a form of energy that was originally implemented by Thermal Expansion 3, replacing the previously used Minecraft Joules and thereby removing the dependency on BuildCraft. RF acts as a highly simplified form of electricity that is designed to be easy to use and low on server impact.

Introduced in CoFH Core and later made available as a separate mod, RF was created as an API that allowed any mod to utilize it as its power system. Due to the large amount of mods that have since implemented it, RF created an era of cross-mod interactions and compatibility, enabling players to generate, transport, and consume power with machines and devices from different mods simultaneously.

In Minecraft versions 1.12 and later, many mods that originally depended on the Redstone Flux API now use the functionally equivalent Forge Energy (FE) system, which is included in Forge and has largely replaced the RF API. However, the "RF" designation remains common, due to the continuous popularity of Thermal Expansion and its related mods. As such the terms RF and FE are often used interchangeably.

Description
Redstone Flux is a very simple power system. Unlike real electricity, circuits do not need to be complete to use Redstone Flux. It is usually produced in generator machines and often transported with cables (and sometimes wirelessly). It can then be consumed by many different machines and items, or be stored for later use.

The smallest possible unit of power is 1 RF. Thus, specific amounts of RF are always described in whole numbers, e.g. 100 RF.

Unlike Energy Units, RF does not use a voltage system. Machines, generators and energy transport are only limited by the amount of RF they can accept, use, output, or transport per tick. Thus, energy rates are described as Redstone Flux per tick, shortened to RF/t (RF per tick). For example, a basic Redstone Furnace from Thermal Expansion 5 will use 20 RF/t while running, and is capable of accepting up to 80 RF/t. As Minecraft normally runs at 20 game ticks per second, the machine will use 400 RF per second. However, RF/s is rarely used to describe energy rates – RF/t is prevalent.

Like other concepts in Minecraft, RF may ignore the real-world law of conservation of energy and is not necessarily entropic. Therefore, energy may be created from nothing, transported and stored without any loss, or destroyed ("voided") without being released in another form.

Forge Energy
Forge Energy is an addition to the Forge project introduced in Minecraft version 1.12. It offers an energy system functionally equivalent to RF. Many mods that previously depended on the Redstone Flux API now use FE instead, often choosing to rename the energy to something in line with the mod's theme.

Some examples of renamed Forge Energy implementations:
 * Crystal Flux (CF; Actually Additions)
 * Micro Infinity (µI; Ender IO)
 * Immersive Flux (IF; Immersive Engineering)

Although the RF and FE systems do not directly work with each other, the majority of mods that use one of them also support the other, implementing seamless conversion between them. For this reason, the two energy systems are usually not seen as separate.

Usage
To effectively use RF/FE, the following is needed:
 * energy producers (generators)
 * energy transport (cables or wireless options)
 * energy storage (batteries)
 * energy consumers (machines and items)

Although many mods add various options for each of these mechanics, some choose to omit parts of the chain. This is made possible by the extensive ecosystem surrounding RF/FE. For example, Environmental Tech adds different types of multiblock machines which consume or produce large amounts of RF/FE; however, it does not offer any transport or storage options, relying on other mods to provide this functionality.

Production
Most mods that use RF/FE introduce different generators. The most simple among them will burn solid fuels like coal to produce RF/FE. More advanced generators may consume liquid fuels and/or require a coolant, others are able to use refined or unconventional fuels. Some generators even interact with the environment around them, like Immersive Engineering's Thermoelectric Generator.

Sourcing enough fuel to feed generators or setting up conditions that allow specialized generators to work continuously is often an important part of gameplay. For example, to keep a nuclear reactor from the Big Reactors mod running, it is necessary to provide sufficient amounts of Yellorium, often mined by an automated quarry or generated by setups like Environmental Tech's Void Ore Miner.

Transport
RF/FE is commonly transported through cable-like structures, like Thermal Dynamics' fluxducts or Ender IO's Energy Conduits. As there is no voltage mechanic, these are often limited only by their energy flow rates. As players first begin to use RF/FE, they are usually able to craft cheap cables that allow them to transport RF/FE between their first generators and energy-consuming machines. With advancing technology and rising energy requirements, they will eventually need to replace them with better cables as the cheap ones will prove to be unable to keep up.

Some mods offer more creative ways of transporting energy. Draconic Evolution, for example, adds Energy Crystals which transport energy wirelessly between each other, and additionally provides the ability to power machines without requiring a physical connection to the energy network.

By design, RF and FE are transported losslessly. However, it is possible for mods to introduce energy loss mechanics. The Energy Laser Relay, for example, loses 5% of the FE it carries by default.

Various ways of transporting energy over vast distances and even across dimensions exist. Examples include the Quantum Entangloporter and Dimensional Transceiver. One of the most popular options, though obsolete as of Thermal Expansion 5, is the Tesseract. Devices of this type are able to transport items and fluids in addition to RF/FE energy, sometimes incurring an energy cost for these functions. Some energy may be consumed or lost during energy transport as well.

As previously mentioned, most forms of RF/FE energy transport support both RF and FE and will convert between them as needed. Mekanism's Universal Cables can, by default, convert to and from Energy Units as well as RF and FE.

Storage
While energy storage is not strictly necessary, it is often instrumental in providing continuous power supply. The player will find it practical to generate more power than they normally use and store any excess, so that additional machines can be used for a while even when power generation is insufficient to run everything at the same time.

Smaller batteries like the Basic Capacitor Bank, Basic Energy Cube, or Energy Cells are often available early on. They can usually be upgraded to store more energy and allow higher energy transfer rates.

Some mods feature more advanced energy storage solutions, often multiblock structures. Ender IO's Capacitor Banks can be used alone, but can also be connected to form multiblock structures of any size and shape. Mekanism's Induction Matrix is a much more expensive structure, but can be built to store massive amounts of energy – even rivaling Draconic Evolution's Energy Core, one of the most well-known energy storage solutions that can be built in various sizes; the largest and most expensive variant can store near-infinite amounts of energy.

Large energy storage facilitates more unconventional sources of power that create extreme amounts of RF/FE but only for a short time, like Lightning Rods.

In many cases, the efficiency of Redstone-sensitive power generators may be increased by turning them off while the player's energy storage is full. This can be achieved by using the chosen energy storage system's own Redstone capabilities (if available), or perhaps with a Redstone Comparator, which some batteries support. The player can improve this method with specialized devices like the Power Monitor, which allows turning generators off shortly before the storage is full, only turning it back on when the storage is close to empty. An advanced logic system like Integrated Dynamics may also be used instead.

Consumption
Many different machines, ranging from simple furnaces to much more complex mechanisms like fully automated farms, are able to consume RF/FE. They generally use a set amount of energy for the execution of a specific job. Often, machines can be upgraded so that they will require less energy or work faster.

Items are able to use and be charged with RF/FE as well. Many mods add armor pieces, tools, weapons, or Baubles that consume energy, often using power to replace the durability mechanic, or providing additional functionality when powered. Inventory batteries like the Flux Capacitor, which can use their own stored energy to charge the player's other RF/FE-powered items, exist as well.

To make continuous operation easier, RF/FE consumers usually have an internal buffer of energy to counterbalance fluctuating energy supply or consumption rates. While it is necessary to supply a machine with an adequate rate of energy to have it work at full speed, many machines will still work with insufficient energy rates. Low energy situations can be handled in various ways:
 * 1) The machine slows down its working speed when it receives less RF/t (or FE/t) than it would use when working at full speed, continuing to work at a pace corresponding to the energy rate it currently receives (e.g. Thermal Expansion machines);
 * 2) the machine pauses its work when its internal energy buffer is empty, resuming its current action for a short time when a small amount of energy is stored in the buffer – this effectively reduces the machine's speed but keeps it functional, though less elegantly (e.g. Mekanism machines);
 * 3) the machine will always wait until it has enough energy stored to complete its next action before it begins working (e.g. Draconic Evolution's Mob Grinder);
 * 4) the machine stops working entirely when the internal energy buffer is empty and resets its work progress, thereby forcing the player to provide the machine with the full energy rate required to have it work at full speed (e.g. NuclearCraft machines).

The vast majority of RF/FE-powered items, on the other hand, will almost always stop working entirely (or lose the additional functions they gain by being powered) if they do not have enough RF/FE stored to complete an action.