Bio Generator

The Bio Generator is an early generator built like a small farm biogas plant. A feed hopper drops food and plant matter into a digester tank, where it rots into biogas. The gas collects under a membrane dome, and a small gas engine burns it for FE. Potatoes, carrots, bread, saplings, and seeds all work straight from the farm, and prepared biomass from the Wooden Composter and Algae Photobioreactor lasts much longer. See Power Chains for how it fits beside the main generators. Later, a Fluid Pump turns the same generator into a Methane source for the Stage 6 chain; see Methane take-off.

Each Bio Generator you craft rolls its own rarity and affixes. It does not have Machine Mastery.

Obtaining

Crafting

Ingredients	Crafting recipe
Glass + Copper Ingot + Plant Reagent + Composter + Redstone Dust + Fuel Chamber

Breaking

Mine it with a pickaxe to get it back. Fuel and installed Gear drop as separate items. Methane and Carbon Exhaust in its tanks are lost.

Usage

Generating power

Put fuel in the fuel slot on the Process tab. Power comes in three steps, and you can watch each one on the block:

1. Digester. The digester takes one item at a time from the hopper and turns it into biogas at about 8 FE/t before stats. A fuel's FE value decides how long it digests: a Composted Biomass worth 1,600 FE takes 200 ticks (10 seconds). The sight glass on the tank shows the current item's slurry level falling, with bubbles while gas forms.
2. Gas holder. Biogas collects under the dome on top of the tank, which swells as it fills. It holds 1,600 FE of gas.
3. Engine. The gas engine starts once the holder has 400 FE of gas, then runs at the digester's pace until the holder is empty. Its flywheel spins and the stack puffs exhaust while it runs, and the lamp on the hopper lights. The gauge on the engine shows the holder's pressure, with the amber band below the start pressure.

A freshly fed generator therefore waits a few seconds before the first FE while the gas pressure builds. The last of the gas still burns when the hopper runs dry, so no fuel is lost.

Generated FE goes into a small internal buffer, plus any installed Battery Cell, and the generator pushes it out to adjacent blocks on every side, for example a Universal Cable. The generator does not limit its own output, so the receiver or connector tier decides how much FE moves each tick. When the buffer is full, the engine idles and the digester keeps filling the gas holder. Once the holder is full too, the digester waits. Nothing is wasted. The generator never accepts FE from outside.

Golden Apples, Enchanted Golden Apples, and Golden Carrots are refused.

Retention time

The dial above the digestion bar on the Process tab sets the retention time: how many days the feed stays in the digester. Click or scroll it. Real digesters work the same way: a short stay pushes feed through faster but leaves gas undigested, and a long stay digests more of each load but makes gas slowly.

Retention	FE/t	FE per item	Unrolled generator	Rich Biomass
10 days	1.60x	0.80x	13 FE/t	2,560 FE
15 days	1.23x	0.92x	10 FE/t	2,954 FE
20 days (rated)	1.00x	1.00x	8 FE/t	3,200 FE
30 days	0.73x	1.09x	6 FE/t	3,491 FE
40 days	0.57x	1.14x	5 FE/t	3,657 FE

The rated 20 days gives every fuel exactly its listed FE at the listed rate. FE/t rounds up like the generator's normal rate. A new retention applies at once, including to the item already digesting. Hover the dial to see the numbers for the item in the hopper.

Fuel

Base FE is at the rated 20-day retention.

Fuel	Items	Base FE
Potatoes		120 (Poisonous Potato: 200)
Carrots		120
Bread		240
Saplings		80
Seeds		40
Other plant biomass		80
Organic Reagent		546
Algae Biomass		400
Composted Biomass		1,600
Dense Algae Biomass		2,400
Rich Biomass		3,200

With JEI installed, all fuels and their values appear in the Bio Generator Fuels category.

Fuel chains

Burning crops directly is the simplest setup, but prepared fuels are worth much more per item:

• Composted Biomass comes from the Wooden Composter, which turns eight units of cheap organic scraps into one item worth 1,600 FE. Crushing seeds into Compost Feedstock in the Crusher first doubles their compost value and comes out well ahead even after the Crusher's power cost.
• Rich Biomass is crafted from Composted Biomass plus Bone Meal, Gunpowder, or Organic Reagent, and is worth 3,200 FE. One Urea turns four Composted Biomass into four Rich Biomass.
• Algae Biomass grows in the Algae Photobioreactor. Craft four into Dense Algae Biomass for a better fuel.
• Organic Reagent comes from crushing potatoes, carrots, and plant biomass. Crushing a potato costs 600 FE and the reagent gives 546 FE, so this path loses a little power unless your Bio Chamber boosts reagent fuel.

Composted Biomass and Rich Biomass are fuel only for the Bio Generator. They are not furnace fuel and do not burn in the Solid Fuel Burner.

Ingredients	Crafting recipe
Rich Biomass Composted Biomass + Any Rich Biomass Catalysts	⇄
Rich Biomass Composted Biomass + Urea	⇄4
Dense Algae Biomass Algae Biomass	⇄

Methane take-off

Instead of burning its gas, the Bio Generator can send it out as Methane for the Steam Methane Reformer. Install a Fluid Pump in one of the two Gas Line slots on the Gear tab. The engine stops, and the generator separates the gas in its holder. Biogas is 60% methane and 40% CO₂:

Gas	Amount in the gas
Methane	1 mB for each 20 FE of gas
CO₂	1 mB of Carbon Exhaust for each 30 FE of gas

A Rich Biomass (3,200 FE) holds 160 mB of Methane and 107 mB of CO₂. Retention, Fuel Efficiency, and the Bio Chamber change the gas per item as they change FE. Energy Generation does not add gas in take-off mode: it only makes the digester work through each item faster, so a well-rolled generator makes Methane faster but needs just as much feed for it. Some Methane always escapes with the CO₂, and the Gas Line slots decide how much:

Gas Line slots	Methane out	CO₂
A Fluid Pump, or two	70%	Vented from the stack
A Fluid Pump and a Biogas Membrane	85–98%, set by the membrane	Captured as Carbon Exhaust
A Biogas Membrane alone	None; the engine runs as normal	Burned with the gas

Methane and Carbon Exhaust collect in two 1,000 mB tanks, shown on the right of the Process tab. Pipes pull both from any face. When the Methane tank is full, the gas holder fills and the digester waits, so no fuel is lost. When the Carbon Exhaust tank is full, the extra CO₂ is vented. Rolled Fluid Capacity on a pump enlarges both tanks, and a second pump adds its own. To empty the tanks, sneak and use a Purge Bucket on the generator; it voids up to 1,000 mB, Methane first.

Through the Reformer and the Ammonia chain, the Methane is worth about ten times the FE the engine makes from the same gas. A Melter gets far more Methane from each item, so send Algae Biomass and Organic Reagent there, and give the take-off crops and compost from a large farm. Several old Bio Generators together feed one Reformer.

Biogas Membrane

A Biogas Membrane is assembled in the Component Assembler from a Calibrated Storage Component, two Rubber, and a Titanium Plate. Its Methane recovery is fixed when it is made: 85%, plus up to 13% more from the calibration stability of the component, so a stability 80 component gives about 95%. The tooltip shows the recovery. Membranes do not roll affixes.

Input		Output	Time	Energy	Rolls traits	Record calibration
2	→		12 s	6,000 FE	No	Yes

Gear

The Gear tab has four optional slots:

• Battery Cell: adds FE storage on top of the internal buffer. Stage 0–3 cells fit, including the Voltaic Potato Battery Cell.
• Bio Chamber: a Bio Chamber adds its rolled power modifiers, and shows as a green culture canister in front of the sight glass. Besides generic FE/t and fuel-duration bonuses, it can roll bonuses for one fuel family, such as potatoes, seeds, Composted Biomass, or algae. These apply only while that family is digesting, and a specific family like saplings uses its own bonus rather than the general plant bonus.
• Gas Line (two slots): each takes any Fluid Pump or a Biogas Membrane. A pump starts the Methane take-off. A pump and a membrane show beside the engine while installed.

Automation

Connectors work on any side: every face inserts fuel and exports FE to adjacent receivers, and no face accepts FE. With a Fluid Pump installed, every face also gives Methane and Carbon Exhaust, and no face accepts fluid. The automation port on the back, the plant's grid-connection cabinet with a copper-pinned socket in its door and a copper conduit from the engine, marks the spot where a Universal Cable connector seats flush against the machine.

Automation cannot extract items, and the Gear slots are installed by hand.

Screen

The Bio Generator screen has four tabs:

• Process: fuel slot, the retention dial, digestion progress, the gas holder gauge with its engine start mark, stored FE, the Methane and Carbon Exhaust tanks, and status icons. Hover for exact values.
• Gear: Battery Cell, Bio Chamber, and two Gas Line slots.
• Stats: the generator's current stats, including traits and Gear.
• Refinement: refine the placed generator's traits with a catalyst.

Data values

Name	Resource location	Form	Translation key
Bio Generator	rngtech:bio_generator	Block	block.rngtech.bio_generator
Biogas Membrane	rngtech:biogas_membrane	Item	item.rngtech.biogas_membrane

See also

• Wooden Composter and Algae Photobioreactor, which make prepared fuel.
• Solid Fuel Burner
• Machine Stats

RNGTech wiki

Guides	Automation · Battery Cells · Dormant Machines · Gear · Getting Started · Heat · Machine Mastery · Machine Stats · Modpack Creators · Power Chains · Rarity and Affixes · Stages · Uniques
Processing	Alloy Furnace · Component Assembler · Component Recycler · Crusher · Furnace · Melter · Metal Press · Resonance Calibrator · Wooden Composter
Power generation	Bio Generator · Cavitation Generator · Corrosion Cell · Fuel Cell · Potential Reactor · Solar Panel · Solid Fuel Burner · Syngas Combustor · Vacuum Collapse Generator
Energy storage	Battery Chassis
Fluids and gases	Algae Photobioreactor · Ammonia Synthesizer · Coal Gasifier · Fluid and Compressor Tanks · Silica Gel Dehumidifier · Steam Methane Reformer · Wooden Dehumidifier
Refinement	Affix Forge · Exotic Affix Forge
Logistics	Universal Cable
Tools	Forestry Cart Station · Miner's Companion · Modular Tools · Tool Bench