What Equipment Is Required to Build a Biogas Plant?
A complete biogas plant needs ten systems: feedstock reception and pre-treatment, digester tanks with heating and mixing, a gas holder or storage, gas cleaning (H₂S removal, drying, chilling), a flare, the energy conversion unit (CHP genset or upgrading plant), digestate storage and separation, pumps and piping, electrical and control with SCADA, and safety equipment. Digester tanks typically represent 25–35% of equipment CAPEX and the energy unit 25–40%.
The Core Process Equipment
Digester tanks are the heart of the plant: insulated, heated to 35–38 °C, and mixed to keep solids in suspension and prevent scum. Above or beside them sits the gas holder, either an integrated membrane dome on the tank roof or a separate vessel, providing buffer between continuous gas production and steady engine demand. Mixing is critical—poor mixing can cost 10–20% of achievable gas yield.
Comparative Data Table: Main Equipment and Cost Share
| Equipment | Function | Share of equipment CAPEX |
| Feedstock reception and pre-treatment | storage, maceration, pasteurisation, grit removal | 10–20% |
| Digester tanks with heating and mixing | anaerobic conversion of volatile solids | 25–35% |
| Gas holder and gas pipework | buffer storage, pressure stability | 4–8% |
| Gas cleaning (H₂S, moisture, siloxane) | protect engines and catalysts | 5–10% |
| CHP genset or upgrading plant | convert gas to power or biomethane | 25–40% |
| Flare | safe disposal of surplus gas | 1–3% |
| Digestate storage and separator | post-digestion handling, fertiliser | 5–10% |
| Electrical, control and SCADA | automation, monitoring, reporting | 8–12% |
What Is Easy to Forget in the Budget
Four items are routinely missed. Gas cleaning is specified for today’s H₂S level, but feedstock drift can push it past design; engines need H₂S below roughly 100–250 ppmv and siloxane removal for catalysts. The flare is not optional—it is what makes startup, shutdown, and upset safe. Dewatering and pasteurisation of co-substrate add real cost. And the gas analyser plus flow meter are what you will actually defend the guarantee with.
Frequently Asked Questions (FAQ)
Q1: What equipment is required to build a biogas plant?
A: Ten systems: feedstock reception and pre-treatment, digester tanks with heating and mixing, gas holder, gas cleaning for H₂S and moisture, flare, CHP genset or upgrading unit, digestate storage and separation, pumps and pipework, electrical and SCADA control, and safety systems.
Q2: What does a digester package include?
A: Usually the tank shell with corrosion protection, insulation and cladding, a heating system, submersible or shaft mixers, gas-tight roof with the gas holder, inlet and outlet structures, and instrumentation for temperature, level, and pressure.
Q3: Why is H2S removal necessary?
A: Hydrogen sulphide corrodes engine components and forms SO₂ on combustion. Keeping it below roughly 100–250 ppmv protects the genset and keeps emissions compliant; biological desulphurisation in the digester headspace is the common low-cost first step.
Q4: What share of cost is the digester?
A: Typically 25–35% of equipment cost, with the energy conversion unit at 25–40% and pre-treatment at 10–20%. Civil works, grid connection, and engineering are usually counted separately from equipment.