The Tekkit Classic Wiki
The Tekkit Classic Wiki

The Geothermal Generator is an IC2 Machine used to generate EU. It works on the same basic principle as normal Generators do, except in this case they use the heat of Lava to generate electricity. Geothermal Generators accept both Lava Buckets and Lava Cells. The Lava Cells are stackable and thus require less maintenance, but cost 4 Tin ingots to produce. Lava source blocks (obtained from NEI or crafted using UU-Matter) cannot be used.

It has an advantage over normal generators in that it does not waste power. For example, if you have a Geothermal Generator hooked up to an MFE Unit which is powering a Rotary Macerator (or any other machine with a small but constant power drain), a normal Generator will start cooking one coal and cook off the entire thing regardless of whether or not all the power is used. However, a Geothermal Generator will rapidly turn on and shut off, only using lava when needed.

The Geothermal Generator will connect to Waterproof Pipes, and will receive Lava carried by them. It will also accept lava directly from an adjacent BuildCraft Pump. It does not need to be pumped into the top; it can be pumped in from any side.




Refined Iron

Empty Cell

Empty Cell




Refined Iron

Geothermal Generator

Raw Materials:

Raw Materials Needed
4 Grid Glass.png Glass

Grid Refined Iron.png

Refined Iron

12 Grid Tin.png Tin
2 Grid Redstone.png Redstone Dust
6 Grid Rubber.png Rubber
3 Grid Copper.png Copper
8 Grid Cobblestone.png


EMC/Piece = 5,051 (>1/2 diamond)*

EMC/Stack = 323,264 (>39 diamonds)*

(*): Assuming you're using an extractor for the sticky resin to get 3 rubber/sticky resin.


As with all Generators, the lava fuel source is inserted into the lower slot, and optionally a RE Battery in the upper slot. Alternatively, lava may be supplied through BuildCraft Waterproof pipes. The Geothermal Generator will charge the battery or output power at a rate of 20 EU/t. A single lava bucket/cell will last approximately 50s, giving off 20000 EU. Filling an MFE with a single Geothermal generator would take 42.5 minutes.

A single Geothermal Generator can store 24 units of lava - thus, inserting a full stack of Lava Cells will instantly use up 24 of them and fill out the lava gauge. The remaining cells would stay in the lower slot and be gradually used.

Geothermal Generator v.s. Engine Generator Comparison Table

Machine Machine Needed to Produce EU Number of EU Producing Machines Fuel used EU per Bucket Buckets Consumed per Hour EU per Hour*
Geothermal Generator None 1 Geothermal Generator Lava 20,000 EU / Bucket 72(about 1 every 50 sec) Buckets / Hour 1,440,000 EU / Hour
Engine Generator Combustion Engine 1 Combustion Engine Lava 52,500 EU / Bucket 3.4 Buckets / Hour 178,500 EU / Hour
Equivalency Point for Engine Generator Combustion Engine (A little more than) 8 Combustion Engines** // 9*** Lava 52,500 EU / Bucket / 1 Combustion Engines // 52,500 27.2 Buckets / Hour / 8 Combustion Engines // 30.6

1,428,000 EU / Hour / 8 combustion Engines // 1,606,500

(*): Eu per Hour is calculated by multiplying the EU per Bucket value by the number of buckets used per hour therefore, for Geothermal, it is 20,000 EU / Bucket * 72 Buckets / Hour = 1,440,000

(**): about 8.067 or exactly 960/119. this info is provided to show the reader how close the hourly EU production of 8 Combustion Engines linked to an Engine Generator is to a Geothermal Generator

(***): Because 8 Combustion Engines attached to an Engine Generator generates slightly less EU than a Geothermal Generator per hour, I included the energy production numbers for 9 Combustion Engines as well. These numbers follow the double slashes following the 8 Combustion Engines EU / hour calculations. 

Analysis of Table

Whether or not you should use Geothermal Generators depends on your situation. Yes Geothermal Generators generate EU more quickly than an Engine Generator powered by one, or even eight, lava-powered Combustion Engines would. However, Engine Generators extract far more (more than 2 and a half times more) EU for every bucket of lava used than the Geothermal Generator.

So if you want to gain EU quickly, use the Geothermal Generator.

If, however, you want to extract as much EU as possible from each lava bucket, use the Engine Generator with a bunch of lava-powered Combustion Engines.

Strategies around lava found on the map

At the very start of the game it suffices to feed the Geothermal Generator with a couple of lava buckets. This makes a surface lava lake a great starting location. Because the Geothermal Generator delivers great power for just a few building materials, you can build other types of machines early on.

If you find a big lava lake like a flooded ravine you can opt to race for Teleport Pipes. This will allow you to drain and use thousands of buckets of lava to use high power tools like a mining laser early on.

Supplying with EE lava


Tekkit Classic - Infinite Power! (EE IC2 RedPower)

It is possible to produce infinite power with geothermal generators by using an Energy Condenser to produce lava. One way of implementing this is by condensing lava buckets, feeding them into the generator(s), then cycling the emptied buckets back into the condenser, giving an economy of 64 EMC/lava unit. Alternatively, condensing lava cells gives a lower economy of 128 EMC/lava unit but as the cells are consumed by the generator, they do not need to be cycled back which simplifies the system massively, allowing for more compact generator arrays.

One issue with this setup is Buildcraft's pipes overflowing and throwing out some of the lava buckets/cells once the Energy Condenser is full. To fix this, simply place Redpower's Transposer one block above the Wooden Pipe connected to the Condenser. Connect the Transposer to another Condenser using Pneumatic Tube. Place a Timer beside the Transposer, and it set it pulse every 0.40 seconds. You could also use the Advanced Insertion Pipes to bypass inserting cells or buckets into a full generator and have it just cycle to another location if all of the generators are full, such as another Energy Condenser or a chest to store Lava Cells.

A second solution is to eliminate the need for Buildcraft parts entirely and use a Redpower Filter with Pneumatic Tubes to send Lava Cells to the Geothermal Generator. Connect a Timer to the Filter and pulse every ~50 seconds (the approximate rate of consumption for 1 Lava Cell). Overflow will simply flow back into the Filter for storage, eliminating the messy spillage that can happen with BuildCraft apparati.

Efficient setup

An efficient setup using Equivalent Exchange.

Using an Energy Condenser, Collector, and Antimatter Relay to produce Lava Cells is an efficient way to produce electrical energy. The cells can be pumped directly into the Generator. An advantage to this is having no buckets left over, allowing for more compact systems. Hooking it up to a lava lake in the Nether provides almost infinite energy as well. If the Nether method is used then it is recommended that multiple Geothermal Generators are used, as well as an MFSUto store all the EU. Since Power Teleport Pipe cannot be used to transfer EU from the Nether to the Overworld.Lapotron Crystal should be used to transfer. This can be done simply by charging the Lapotron Crystal in the Nether and depositing the EU in the overworld.


Storage: 480,000 EU

Note that the 480,000 EU that is "stored" is the amount of energy that can be created from the 24 Lava Cells or Lava Buckets the Geothermal Generator can store. The machine has no true EU storage as such.

Input: Lava Buckets, Lava Cells, or Lava pumped in directly from Waterproof Pipes.

Output: 20,000 EU per Lava Bucket or Lava Cell at a rate of 20 EU/t. Each Lava unit lasts 50 seconds.


Using Equivalent Exchange, you can make more lava cells or lava buckets and pump it into the geothermal generator, creating a very effcient way to produce energy, especially using Energy Collectors and Antimatter Relays, as this would provide for an infinite lava source.

Using 2 Ender Chests, a player can pump lava from the Nether into the Overworld, providing unlimited power.


  • The MK2 Geothermal Generator exists, but is unable to be crafted, as in early versions players were unable to pump lava straight into a Geothermal Generator. By removing this block, any previous worlds that contained it would break.

Video Tutorial

Tekkit_Tutorial_Showcase_Infinite_EU_and_6_UU-Matter_Per_Minute! How_to_Build_Episode_2_-_Tekkit_-_Automatic_and_Infinite_Geothermal_Reactor Minecraft_Technic_Part_15_Geothermal_Generator_and_the_LapPack! Geothermal_Generator_-_Minecraft_In_Minutes How_to_Build_Episode_2_-_Tekkit_-_Automatic_and_Infinite_Geothermal_Reactor_MK2