Biogas and Biomethane: towards sustainable and circular energy
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The energy transition is one of the most urgent challenges of our time. In this scenario, biogas and biomethane emerge as fundamental pillars for combining energy self-sufficiency with environmental sustainability. They are not simply renewable energy sources, but essential links in the circular economy, capable of valorizing waste and by-products in a zero-waste model.
Italy, in particular, is investing significantly in these technologies, with the aim of reducing dependence on fossil fuels and creating new economic and rural opportunities. For companies and farmers, understanding the technology, raw materials, and certification obligations is crucial to fully exploiting the benefits offered by these supply chains.
The technology: from Biogas to Biomethane
Although often used interchangeably, Biogas and Biomethane represent different phases of the same biological process.
1. Biogas: the anaerobic digestion process
Biogas is a combustible gas produced by anaerobic digestion, a natural biochemical process that occurs in the absence of oxygen. The process takes place inside sealed reactors called anaerobic digesters.
Raw materials (substrates): the process uses a wide range of biomasses and organic waste.
- Agricultural waste: livestock effluents (slurry and manure), dedicated crops (e.g., maize or triticale silage), and agricultural by-products.
- Organic waste: FORSU (organic fraction of municipal solid waste) and food industry waste.
- Sewage sludge: residues from wastewater treatment.
Composition: biogas is mainly composed of methane (CH4, 50-75%) and carbon dioxide (CO2, 25-45%), plus traces of other gases (such as hydrogen sulfide).
The biogas produced in this way is typically used on-site for the combined production of electricity and heat (cogeneration).
2. Biomethane: the upgrade of renewable gas
Biomethane is biogas that has undergone a purification process, known as upgrading. This process removes CO2 and other contaminants to bring the methane concentration to very high levels (over 97%), making it equivalent to natural gas of fossil origin.
Advantages of upgrading:
- Grid injection: biomethane can be injected directly into the national gas grid (snam), making energy available throughout the territory.
- Advanced fuel: it can be compressed (bio-cng) or liquefied (bio-lng) for use as a sustainable fuel in the transport sector (heavy vehicles, ships).
The choice of raw materials and environmental sustainability
The sustainability of Biogas and Biomethane production critically depends on the nature of the substrates used. Italian and European Union regulations strongly incentivize the use of advanced raw materials to maximize environmental benefit.
Admitted and sustainable raw materials
The current regulatory framework (particularly the fer 2 decree) prioritizes the following categories for access to incentives:
- By-products and waste: raw materials that do not compete with the food supply chain, such as manure, straw, pruning residues, and agro-industrial waste.
- Second-harvest crops: energy crops grown on land not intended for primary food production, often used as cover crops between one main harvest and the next, also improving soil health.
- Waste: forsu and sludge, thus valorizing urban and industrial waste.
The use of these raw materials strengthens the circular economy, reduces waste management, and mitigates climate-changing emissions resulting from the uncontrolled decomposition of waste.
Opportunities and Certification Obligations in Italy
The Italian regulatory framework, in line with the European renewable energy directive (RED II), establishes clear rules for access to incentives and for the certification of the sustainability of biomethane production.
1. The incentive system: the biomethane decree (dm 2022)
The biomethane decree 2022 has relaunched the sector, providing a support system based on:
- Incentive tariffs: all-inclusive tariffs for the energy produced.
- Capital contributions: funds for the reconversion of existing biogas plants or the construction of new plants, often financed through the PNRR (national recovery and resilience plan).
Access to these mechanisms is bound by compliance with rigorous sustainability criteria.
2. Sustainability Certification (RED II)
To sell biomethane into the grid or use it as a biofuel, it is mandatory to demonstrate that the raw material used complies with the sustainability criteria set out in RED II.
Key criteria:
- GHG Emission reduction: biomethane must guarantee a minimum reduction in greenhouse gas emissions compared to the reference fossil fuel (usually, at least 65%).
- Land use: raw materials must not come from areas with high biodiversity or high carbon stock (e.g., primary forests or peatlands).
- Certification scheme: sustainability is verified by an accredited independent certification body, which issues a certificate confirming the chain of custody and mass balances.
3. Certificates of Release for Consumption (cic)
The main incentive mechanism for advanced and waste-derived biomethane is linked to the Certificates of Release for Consumption (cic), tradable certificates issued by the energy services management.
Functioning: each batch of biomethane injected into the grid, whose sustainability has been certified, entitles the holder to a certain number of cics. These certificates are purchased by fuel distributors, who are obliged to blend a quota of renewable biofuels into the total fuels sold.
4. The role of the CIB and technical rules
The Italian biogas and natural gas for traction consortium (cib) plays a crucial role, acting as a regulatory and technical reference point for sector operators. For grid injection, plants must comply with the technical rules for connection and the gas quality standards established by the energy, networks and environment regulatory authority (arera).
Multiple advantages of the Biogas-Biomethane supply chain
Adopting the biogas/biomethane supply chain offers benefits that go beyond simple energy production:
| Category | Key Advantage | Description |
|---|---|---|
| Environmental | Carbon neutrality and emission reduction | Capturing Methane from waste prevents its dispersal into the atmosphere, contributing significantly to the reduction of greenhouse gas emissions. |
Circular economy | Valorization of waste | Transforms agricultural waste and refuse into resources, reducing disposal costs and creating an alternative source of income. |
Agriculture | Digestate production | The solid and liquid residue from the digester (digestate) is a high-quality organic fertilizer that can replace chemical fertilizers, improving soil health. |
Energy | Flexibility and storage | Unlike wind or solar, biomethane is storable and injectable into the existing gas network, guaranteeing flexibility and security of supply. |
Prometheus’s support for your sustainable plant
The construction and management of a biogas or biomethane plant in Italy is a complex undertaking that requires careful navigation of the regulatory, technical, and financial framework. compliance with RED II criteria and energy services management procedures are fundamental for obtaining incentives.
Prometheus offers a specialized consulting service that covers the entire project life cycle:
- 1. Feasibility studies: analysis of raw materials, energy balances, and evaluation of sustainable production potential.
- 2. Regulatory compliance and incentives: management of procedures for accessing PNRR contributions.
- 3. RED II Certification: comprehensive support for biomass sustainability compliance and the acquisition of requisite certifications.
If you are an agricultural or industrial company and want to transform your waste into renewable energy and economic value, contact our experts for a preliminary assessment and discover how to maximize your sustainable biomethane production.
