Selecting the right bio-LNG plant depends on your biogas composition, production scale, site conditions, technology preferences, budget, and operational requirements. Key factors include plant capacity, upgrading and liquefaction technology, design flexibility, resource needs, total cost of ownership, and lead time. This page guides you through each decision point to help you choose a bio-LNG solution that fits your project.
Key factors when selecting a bio-LNG plant:
- Biogas source and composition – methane content, contaminants, flow stability
- Target production capacity – daily bio-LNG output (e.g., 5–45 tonnes/day)
- Technology fit – upgrading method, liquefaction approach, energy efficiency
- Site and infrastructure – space, utilities, truck access, grid connection
- Operational model – single vs. multiple train, turndown capability, automation level
- Product specifications – offtaker requirements for purity, temperature, CO₂ handling
- Total cost of ownership – CAPEX (pretreatment, upgrading, liquefaction, CO₂), OPEX, lead time
- Supplier track record – proven technology, uptime, support, reference sites
What process steps should a bio-LNG plant include?
When selecting a bio-LNG plant, ensure it covers all essential process steps to turn raw biogas into two valuable products: liquid bio-LNG and biogenic CO₂.
It starts with pretreatment of the raw biogas, where impurities such as water, hydrogen sulphide (H₂S), and volatile organic compounds (VOCs) are removed. In the next step, known as upgrading, CO₂ is separated from the gas, leaving purified methane (biomethane). This methane is then cooled to a temperature below -150°C, turning it into liquid bio-LNG. The captured CO₂ can also be liquefied to enable efficient transport and reuse as a valuable co-product.
A complete bio-LNG plant integrates all four steps: pretreatment, upgrading, liquefaction, and optionally CO₂ liquefaction.
What production technologies are available, and how do they compare?
There are several proven technologies for upgrading biogas (such as membrane separation, pressure swing adsorption, and amine scrubbing) and for liquefaction (such as expansion cycles and mixed refrigerant systems). When comparing them, it’s important to look beyond just the core process and consider the full operational footprint:
Plant capacity: Some solutions perform better at very small or very large scale. Nordsol’s sweet spot is 5–45 tonnes per day.
Resource needs: Does the system require chemicals, heat, electricity, cooling water, or consumables like adsorption media?
Reliability: What is the uptime of the plant in practice? A visit to a live installation is often the best way to find out.
Operational costs: Think about staffing, loading and unloading logistics, and the maintenance required to keep things running smoothly.
What factors should I consider when selecting and designing a bio-LNG plant?
Several factors influence both the selection and technical design of your plant:
Biogas composition and flow: Know your typical, minimum, and maximum methane levels.
Storage requirements: How much on-site storage is needed for bio-LNG and liquefied CO₂? What are your offtaker’s demands and transport options?
Product specifications: Different offtakers may require specific temperatures or limits on oxygen and nitrogen content.
Site logistics: Ensure safe access for trucks, loading bays that aren’t blocked, and emergency routes.
Turndown capability: Decide at what biogas flow the plant should be able to operate; 30% or 50% of nominal flow, for instance.
Utilities: Secure reliable access to power, compressed air, and nitrogen.
Safety: The plant should be intrinsically safe and continuously monitored. Nordsol’s systems include automatic shut-off valves, pressure relief mechanisms, and predictive maintenance tools.
Should I choose a single-train or multiple-train bio-LNG plant?
Larger bio-LNG plants (typically above 15–20 tonnes per day) often benefit from a multiple-train setup: several smaller, parallel systems rather than one large unit. Compared to a single large train, this approach offers:
Redundancy: If one train is offline for maintenance, the others can keep running.
Improved uptime: Maintenance can be scheduled across trains without full shutdowns.
Easier operations: Identical units simplify spare parts management and reduce downtime.
Energy efficiency: Smaller trains run closer to their optimal load, saving energy when operating at partial capacity.
Grid compatibility: Multiple smaller trains can run at low voltage (400V), avoiding costly high-voltage connections.
Modular rollout: Building the plant train-by-train makes large projects more flexible and manageable.
Do I need a gas grid connection to run a bio-LNG plant?
No, a gas grid connection is not required. However, it can add operational flexibility. For example, if you want to sell excess biomethane to the grid during maintenance or respond to energy market opportunities.
Keep in mind that a gas grid connection comes with infrastructure costs and regulatory requirements. An alternative is to integrate a CHP unit (Combined Heat and Power), which allows you to use biogas for on-site power and heat during planned downtime.
Important: Some systems allow liquefaction of natural gas from the grid, but this produces fossil LNG, not bio-LNG. It also makes little energy or environmental sense, as a significant part of European pipeline gas originated as LNG and re-liquefying it adds unnecessary cost and emissions. Nordsol plants are designed specifically for biogas-derived biomethane, not fossil hydrocarbons.
How is the total cost of a bio-LNG plant structured?
Bio-LNG plants are typically built around four key investment blocks:
1. Pretreatment – Removing contaminants (H₂S, siloxanes, moisture, particles) from raw biogas.
2. Upgrading – Separating CO₂ to produce biomethane (>95% CH₄).
3. Liquefaction – Turning methane into liquid bio-LNG; includes coldbox, compressors, storage, and loading station. Of the four blocks, this one requires the highest investment.
4. CO₂ liquefaction – This block is optional, but often economically viable and can improve overall project profitability.
What is the lead time for a bio-LNG plant?
The full timeline from contract to commissioning is usually 15–17 months:
13–15 months for engineering, pre-fabrication, and delivery.
2–3 months for site integration, testing, and start-up.
Ready to select the right bio-LNG plant for your project?
Every biogas site is different. The optimal plant configuration depends on your specific feedstock, production scale, site infrastructure, offtake requirements, and budget.
Nordsol specialises in modular, proven bio-LNG installations tailored to decentralised biogas sites in the 5–45 tonnes per day range. Our plants draw on deep expertise in bio-LNG process design and a track record of operational installations across Europe.
Contact our team to discuss your project, or explore our other FAQs.
