MJ is the energy that BuildCraft 3 uses. MJ stands for Minecraft Joules. It is generated by any kind of Engine and can be used by any kind of BuildCraft machinery. Many types of energy can be converted to MJ by using Engines, however, transforming MJ into other power types is a more complex process, and needs the use of other mods machines. MJ can travel through Conductive Pipes and Redstone Energy Conduit

Generation Edit

MJs are made by all types of Engines. Redstone Engines generate MJ just with a redstone signal, but others like the Combustion Engine need Fuel or other resources to produce MJ. Since Redstone Engines can only power Wooden Transport Pipes and Wooden Waterproof Pipes, a higher-tier engine is needed in order to power machinery.

List of EnginesEdit

Name Max Output (MJ/t) Source Mod
Biogas Engine 5 Forestry
Blulectric Engine 23+ RedPower 2
Combustion Engine 6 Buildcraft 3
Commercial Steam Engine 4 Railcraft
Electrical Engine 14


Hobbyist's Steam Engine 2 Railcraft
Industrial Steam Engine 8 Railcraft
Magmatic Engine 4 Thermal Expansion
Peat-fired Engine 1 Forestry
Redstone Engine 0.05 Buildcraft 3
Steam Engine 2 Thermal Expansion
Stirling (Steam) Engine 1 Buildcraft 3

Transportation Edit

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Some Golden Conductive Pipes carrying MJ. The cyan beam in the pipes is MJ.

Engines can place their MJ into a machine, a Wooden Conductive Pipe (which can be then attached to other Conductive Pipes), or a Redstone Energy Conduit with the arrow pointing out of the machine.

Conductive Pipes are like wire for MJ to travel through. Stone Conductive Pipes have a 1% energy loss by each block, and Golden Conductive Pipes have a 0.01% energy loss by block. When MJ is traveling through a Conductive Pipe, a cyan beam is seen inside the pipes. MJ traveling a Conductive Pipe is seen in the right of this page, note the cyan beam inside the pipe.

To see more information see Conductive Pipes

Conversion Edit

Other power types can be converted into MJ. EU, IndustrialCraft 2's power, can be converted into MJ by using an Electrical Engine. Blutricity, RedPower 2's power, can be converted into MJ by using a Blulectric Engine, which takes blutricity and outputs MJ. MJ can be converted into EU by powering a Magma Crucible with Netherrack or Cobblestone inside it that generates lava, and then put that lava into a Geothermal Generator or a Thermal Generator; the Magma Crucible will take MJ and the generator will output EU, with an efficiency that depends on what resource is melted in the crucible and which generator is used to extract EU. The most efficient version of this process allows the resulting EU to be converted back into MJ with a properly upgraded Electrical Engine with no loss.

EU ConversionEdit

Lava Source Generator MJ per Lava EU per Lava EU per MJ
Cobblestone Geothermal Generator 24,000 20,000 0.83
Cobblestone Thermal Generator 24,000 30,000 1.25
Netherrack Geothermal Generator 12,000 20,000 1.67
Netherrack Thermal Generator 12,000 30,000 2.5