The biomethane It is now a real part of the energy transition. Behind every biomethane plant There are waste materials that can be converted into renewable gas, as well as technical equipment capable of designing, managing, and operating such a system.
What is biomethane, and how does it differ from biogas and natural gas?
The biomethane is a renewable gas with 98-99% purity in natural gas, obtained by purifying the biogas. It is produced through the decomposition of organic matter and still contains CO₂ and impurities. Once purified, biomethane is interchangeable with natural gas, which is of fossil origin, and can be injected into its network.
What is a biomethane plant, and how does it work?
One biomethane plant converts organic waste into renewable gas in two stages: the anaerobic digestion, which produces biogas, and the upgrading, which purifies it to the quality of natural gas. In addition, it produces digestate, which can be used as fertilizer.
Step-by-Step Biomethane Production Process
These are the four stages. Explore them in the diagram and then in detail.
From Waste to Renewable Gas
Click on each stage to see what goes in, what comes out, and what technical role is involved.
Receipt and Pretreatment of Raw Materials
The waste is weighed, unloaded, and grind or homogenize. Impurities such as plastics or stones, which could interfere with the process, are also removed.
Anaerobic digestion
In digesters In closed, oxygen-free environments, microorganisms break down organic matter. This produces biogas, which is rich in methane, and digestate.
Biogas Purification and Upgrading
The biogas is purified to remove moisture, hydrogen sulfide, and CO₂, using membranes, washed with water or amines, or PSA, up to the purity required by the grid.
Injection into the grid or use in transmission
Biomethane is measured, odorized, and compressed to the point of gas line connection. You can also go to charging stations or industry.
Raw materials: agricultural and livestock waste, food waste (FORSU), and sewage sludge
The raw material determines the design and profitability. Common sources include agricultural waste, slurry and manure, the FORSU, agro-industrial waste y sewage sludge.
Stages of a Biomethane Plant Project: From Feasibility to Operation
Feasibility and Site Selection Study
The following is evaluated: availability of raw materials, the distance to the gas network, the site, and social acceptance. This is where a large part of the project is decided. Check it off with this checklist.
Biomethane Plant Feasibility Checklist
Check off the items you've already completed in your project. Critical items count double.
Guidance tool: This does not replace a technical, economic, and legal feasibility study.
Engineering, Permits, and Financing
Includes design, environmental and energy permits and funding. The processing is the bottleneck: the sector talks about 3 to 5 years by project.
Construction and Commissioning
Digesters are constructed, upgrades are made, and connections are established, and operations are gradually brought online.
Operation and Maintenance
It requires monitoring the biology of the digester, the gas quality and preventive maintenance.
Biomethane Plant: Pros and Cons for the Company
Pros: You recycle waste, generate revenue from renewable gas, produce fertilizer, and reduce emissions. Cons: high investment costs, lengthy processing times, dependence on raw materials, and potential opposition from neighbors due to odors. Industry estimates put the investment at between 12 and 50 million euros.
Uses of biomethane: the gas grid, transportation, and industry
It can injected into the gas network, be used as fuel for heavy-duty vehicles or supply industrial processes difficult to electrify. The Guarantees of Origin demonstrate that they are renewable.
Regulatory Framework and Market in Spain and Europe
The EU aims to 35 bcm of biomethane by 2030 with REPowerEU. In Spain, the technical potential exceeds 160 TWh per year, but actual production is still very low. There is a system of Guarantees of Origin and, in 2026, the government submitted a royal decree with minimum payment of renewable gas in total gas sales.
Technical Roles in Demand for Renewable Gas Projects
Process and Biotechnology Engineers
They design and optimize the anaerobic digestion and upgrading, and they monitor performance.
Energy and Gas Project Engineers
Coordinate engineering, construction, and grid connection, including timelines and a budget.
Operations and Maintenance Technicians
They ensure day-to-day operations: instrumentation, maintenance, and safety with gas.
Environmental and Permitting Specialists
They manage permits, environmental impact studies, odors, and digestate.
How to Train Teams on Renewable Gases and Energy Projects
The industry is growing faster than its talent pool. At Structuralia, you'll find energy and gas programs so that your engineers can master the renewable gases and project management.
Frequently Asked Questions About Biomethane
Are biogas and biomethane the same thing?
No. The biogas is the undigested mixture from digestion; the biomethane It is that purified biogas, which is equivalent to natural gas.
How much does a biomethane plant cost?
It depends on capacity and waste: sector-specific estimates range from 12 to 50 million euros, and there are specific projects related to 35 million.
Is biomethane a renewable energy source?
Yes, if it comes from waste and biomass and meets sustainability criteria, with its guarantee of origin.
What types of waste can be recycled?
Pig manure, horse manure, agricultural and agroindustrial waste, FORSU y sewage sludge.
