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Biomethane is 100% renewable energy obtained from organic waste from agricultural and livestock sources. Through an anaerobic fermentation process (oxygen-free and completely sealed), it is converted into a high-quality gas that is injected directly into the existing natural gas grid.

Waste from the surrounding area is treated and transformed into “digestate”, a high-quality biofertiliser that returns organic matter and the nutrients needed for soil regeneration, and supports compliance with European regulations. All of this makes waste management easier and positions it as a benchmark for Circular Economy, Innovation and Decarbonisation in rural areas.

From a more technical perspective, Biomethane is a renewable gas composed mainly of methane (CH₄) obtained from biogas after a purification process known as upgrading. Once purified, it can be injected into the gas grid as natural gas, or stored and transported as LNG (Liquefied Natural Gas) or CNG (Compressed Natural Gas).

Biogas is the initial product resulting from the anaerobic fermentation of organic waste in the digester. It then undergoes a purification process to obtain Biomethane, a high-quality gas very similar to fossil natural gas. This Biomethane is injected directly into the existing national gas grid infrastructure and blends with the natural gas we use in our homes, offering a greener alternative without requiring substantial changes to infrastructure.

The most important difference is the business model: in the case of Biomethane, the priority is to obtain a high-quality gas through a fully sealed process with strict control of inputs, processing and outputs for each component. In the case of biogas, uses and processes can vary widely.

Biomethane is a benchmark for the Circular Economy and decarbonisation. Plants convert organic waste, such as manure or agricultural residues, into Biomethane, a renewable gas with characteristics similar to natural gas. This process not only prevents methane—a powerful greenhouse gas—from being released into the atmosphere, but also creates high-quality biofertilisers that regenerate agricultural soils. All of this takes place in a controlled, sealed environment, eliminating odour emissions and contamination risks.

Steps to produce Biomethane:

1. Collection of organic feedstock. Our plants have strict intake controls and we only use organic agricultural and livestock waste.
2. Anaerobic digestion (biogas production): the organic matter corresponding to the optimised feedstock mix for each project is introduced into a biodigester, where it breaks down in an oxygen-free, fully sealed environment.
3. Biogas purification: to convert biogas into Biomethane, impurities such as CO₂ (via absorption, membranes or cryogenics), hydrogen sulphide (H₂S) and other components generated during anaerobic digestion are removed. Once purified, the gas has a methane purity above 95%, similar to natural gas, and can be blended with it in the existing Spanish gas grid.

Biomethane can be injected into the natural gas grid or used as:

• Vehicle fuel (BioCNG)
• Electricity and heat generation for industrial or domestic use.

IAM Carbonzero’s Biomethane plants are managed to the highest quality standards and with the best technological innovation. With these state-of-the-art developments, highly significant benefits can be delivered in the areas where they are implemented:

• Promoting the circular economy
• Decarbonisation and energy transition in line with EU targets
• Energy independence
• Reduction of greenhouse gases (GHG)
• Aquifer regeneration
• Regeneration of agricultural soils
• Improved air quality
• Ecosystem regeneration
• Revitalisation of rural areas
• Local economic impact
• Job creation
• Social innovation

Here is how they are very similar:

• Their chemical composition is very similar: once purified, Biomethane contains more than 95% methane, just like fossil natural gas, which is why they can be blended.
• Same infrastructure:
  • It is transported and stored in the same pipelines and tanks as natural gas. In other words, it uses existing infrastructure. It does not require new installations for distribution.
• Same uses:
  • It can be injected into the existing natural gas grid.
  • It can be used as vehicle fuel (BioCNG).
  • It is used in industry, heating and electricity generation.

What is the difference between Biomethane and natural gas?

• Origin: Biomethane is renewable, obtained from organic waste through anaerobic digestion. Natural gas is a fossil fuel, extracted from underground deposits.
• Environmental impact:
  • Biomethane reduces CO₂ emissions because it collects agricultural and livestock waste and ferments it in a sealed process, preventing large amounts of methane and fossil CO₂ from being released into the atmosphere.
  • Natural gas emits CO₂ when burned, and its extraction (fracking) can cause environmental damage.
• Availability:
  • Natural gas has limited reserves and depends on fossil fuel extraction.
  • Biomethane comes from the circular economy, so it can be produced locally on an ongoing basis, reducing energy dependence on other countries.

Europe is the world’s most advanced region in Biomethane production, thanks to climate regulations and economic incentives.

1. France: more than 600 Biomethane plants in operation.
2. Germany: more than 200 Biomethane plants. It uses Biomethane to generate electricity and as vehicle fuel.
3. Sweden: extensive use of BioCNG for buses and trucks.
4. Italy: Biomethane injection into the gas grid since 2017 and more than 133 Biomethane plants (source: EBA and GIE).
5. The Netherlands: has a plan for 30% of gas in 2030 to come from Biomethane. It has more than 55 plants in production.
6. Spain: high potential, but development began recently, so there are few plants: around 11 currently operating and more than 200 projects in the approval process.

Without a doubt. The economic viability of Biomethane rests on regulations that support its development (*), economies of scale, the circular economy and growing demand for renewable energy.

(*) Main EU requirements on renewable energy in Spain:

1. 42% renewables target by 2030
   • Spain, under its National Integrated Energy and Climate Plan (PNIEC), has raised its target to 48% by 2030.
2. Decarbonisation and climate neutrality by 2050
   • Spain must reduce its dependence on fossil gas and oil and increase the use of solar, wind, Biomethane and other renewables.
3. Emissions reduction:
   • Emissions reductions are required in industry, transport and heating.

The production of renewable Biomethane gas is an economic activity based on excellence in environmental best practice. Plants comply with the Best Available Techniques (BAT) for each process, set out in Implementing Decision (EU) 2018/1147. These are therefore projects that require high investment and whose technical-economic viability is studied in every respect.

Project viability is based, among other aspects, on strict control of the digester feedstock mix to ensure stable production throughout the year. In addition, costly preliminary studies are carried out on basic engineering and applicable technology, as well as the corresponding environmental impact assessments. These results confirm the plant’s viability.

Biomethane plants are still largely unknown technologies in Spain. Misinformation and lack of knowledge about this industry are creating significant social alarm, driving the emergence of neighbourhood groups. In the media and on social networks, many examples are shared that mix facts from poor practices in other types of past and recent projects, creating a climate of alert and fear about potential dangers that understandably concerns communities near projects, as they perceive something unknown as a threat. This is normal, which is why we want to help build understanding of how this technology works and the benefits it brings. If you have any questions, write to our information channel hablamos@iamcarbonzero.com and we will be happy to reply.

The country’s energy strategy is still being defined. The energy mix is always the solution.

In the short to medium term: Biomethane can partially replace natural gas in key sectors (transport, industry, heating).

In the long term: with continued investment and development, Biomethane could fully replace fossil gas, complemented by green hydrogen and electrification.

The plants developed by IAM Carbonzero are designed with the most advanced technologies, incorporating sophisticated biofilters that capture and neutralise any potential source of odour within the treatment process. The entire process—from transport, intake and treatment to Biomethane injection into the grid and digestate as biofertiliser—is carried out in a sealed system that includes negative-pressure storage areas and advanced biofilters to capture and neutralise odours.

In addition, all substrate transport is carried out using sealed vehicles to prevent any spillage or odour emissions, and the same approach will be used within the facility by capturing all gases and routing them to an air treatment system for purification. All waste is received and stored in closed buildings or tanks.

This approach ensures an odour-free town and improved air quality. During the operational phase, strict control and constant monitoring are planned. Throughout the plant’s lifetime, we will continue to incorporate innovations as they emerge and the best available techniques.

A Biomethane plant by IAM Carbonzero is completely safe and, as a driver of the circular economy, improves citizens’ quality of life from an environmental, economic and social perspective. It supports the management of agricultural and livestock waste by generating recurring income and new business opportunities. It boosts the local economy by creating jobs directly.

The plant location is assessed while respecting the required distances from population centres based on regulatory and environmental compliance, taking into account proximity to the gas pipeline connection—into which the resulting Biomethane is injected—and the availability of agricultural and livestock waste within an average distance of 15 to 25 kilometres.

Regulations exist to guarantee the safety and comfort of local communities and, in addition, these facilities are designed to minimise risks and operate very efficiently, using the Best Available Techniques. In all phases—construction and operation—strict control and constant monitoring are planned, along with safety and risk-control plans to the highest standards. All projects are supervised by the competent authorities.

By processing agricultural and livestock waste, such as olive pomace or slurry, in a Biomethane plant, it is removed from the fields and the emission of unpleasant odours is significantly reduced, thereby improving air quality and reducing nuisance for nearby communities. The plant’s carbon footprint is negative, which undoubtedly improves the air in the local area.

The Environmental Impact Assessment includes a noise study, ensuring full compliance with regulations and no nuisance to the population. In addition, we avoid routing lorry traffic through the town centre, so that any potential nuisance arising from it is eliminated.

Noise barriers will be implemented and equipment and machinery will be used that meet noise emission standards well above those required by regulations. The environmental project includes a noise map verifying that the plant’s sound level complies with current regulations.

The feedstock is agricultural and livestock waste from farms located, on average, 15 to 25 kilometres from the plant’s planned location.

The remaining material is a quality biofertiliser: digestate. This biofertiliser offers major benefits for local farmers, who have it available nearby.

• They will have simple, local access to stabilised organic fertiliser, supporting compliance with increasingly stringent European regulations (in addition, thanks to anaerobic fermentation at thermophilic process temperature, the digestate is pasteurised).
• Improve production: using digestate as a biofertiliser can help increase agri-food production and raise soil organic matter.
• Preserve green and blue ecosystems: it supports the fight against climate change by reducing GHG and NH₃ emissions, reducing aquifer pollution, preserving and improving biodiversity, and helping to combat drought.

• An IAM Carbonzero Biomethane plant is established and pays taxes locally in the municipality where it is installed; this ensures that taxes are settled with the relevant town council and reinvested in improving residents’ quality of life. We are a neighbour for at least 25 years.
• This type of project boosts the local economy by creating quality direct and indirect employment. Local hiring is always prioritised: more intensively during the construction phase and, during operation, with permanent positions for at least 25 years. In addition, it significantly stimulates the local economy through local services and professionals. This helps retain population and prevents rural depopulation.
• A Biomethane plant provides a major boost to innovation and modernises the primary sector. It helps meet the EU’s increasingly demanding regulations on waste management and the adoption of organic farming with the biofertiliser produced by the process. This reduces dependence on high-cost, highly polluting chemical fertilisers, creating new, more sustainable operating models from an economic and environmental perspective.
• It improves citizens’ quality of life, not only through the economic and social aspects already described, but also through its impact on the surrounding environment. Collecting waste such as slurry—which is highly polluting and generates bad odours—prevents these nuisances and protects natural ecosystems by avoiding seepage into aquifers and contamination of local water and soil. For all these reasons, a Biomethane plant is a CO₂ sink and improves air quality locally.
• IAM Carbonzero takes part in community development forums where it operates and makes social innovation investments aligned with the territory’s development plans.

Plants are designed to optimise water needs and operate with zero discharge, treating and recirculating liquid digestate to minimise external water requirements. This is complemented by rainwater harvesting, which provides the external water supply needed for normal operations. Drinking water is used only for workers’ consumption.

A detailed study of traffic in the area and its surroundings is carried out. Routes are then designed with the priority objective of NOT passing through the centre of urban areas. These are not the shortest routes, but the most suitable ones, ensuring there is no nuisance to residents.

The environmental impact assessment includes an environmental monitoring programme in accordance with the Best Available Techniques. The final environmental monitoring programme will be defined in the environmental impact statement and in the Integrated Environmental Authorisation.

Best Available Techniques:

• Noise control: noise barriers are implemented and equipment and machinery are used that comply with the noise emission standards set by regulations. The environmental project includes a noise map verifying that the plant’s sound level complies with current regulations.
• Control of suspended particles: measures are implemented to control the generation of dust and suspended particles, such as watering roads and work areas, as well as using covers on lorries transporting materials to prevent particle dispersion during transport.
• Traffic management: access and exit routes are designed for transport vehicles to avoid passing through residential areas, and operating hours are established to reduce traffic during peak times.
• Landscape integration: the design aims to minimise visual impact. In addition, IAM Carbonzero always carries out actions at all its plants to improve project integration into the landscape, for example by planting vegetation around the facilities and using materials that harmonise with the surroundings.
• Odour management: all waste is received and stored in closed buildings or tanks. Ventilation air is directed to odour treatment via a biofilter. Likewise, digestate lagoons are covered and gas collection is also directed to the biofilter. This ensures treatment of all potential odour sources at the plant. The effectiveness of the odour treatment system design is verified by preparing an odour map (olfactometry) in the environmental impact assessment and through a monitoring network during plant operation.

Digestate is an organic product obtained after the anaerobic digestion process at a Biomethane plant. Thanks to this controlled process, it retains the nutrients present in agricultural and livestock feedstocks and transforms them into a product with high agronomic value.

Depending on its treatment and the applicable regulations, it can be used as a biofertiliser or as a source of recycled nutrients for agriculture, contributing to a circular economy model.

Digestate is obtained from agricultural and livestock by-products generated in the area around the plant, such as manure, slurry and other authorised organic materials. Our plants do not accept wastewater treatment sludge, nor Category 1 animal by-products, nor slaughterhouse waste. All feedstocks are controlled from reception and remain fully traceable throughout the entire production process.

Because it is part of a circular economy model. The nutrients contained in agricultural and livestock by-products are recovered during the Biomethane production process and returned to the agricultural soils of the territory they come from.

Prioritising its application locally reduces nutrient transport, decreases dependence on mineral fertilisers and helps improve the sustainability of local agriculture.

In addition, it is only applied when there is an agronomic need, in accordance with fertilisation plans and current regulations.

The main difference lies in the process. Slurry or manure are the starting feedstocks. Digestate is the result of a controlled biological anaerobic digestion process that stabilises organic matter, significantly reduces the presence of pathogenic microorganisms and weed seeds, improves the availability of some nutrients, and provides a much more homogeneous, traceable and predictable composition.

Thanks to this process, the product offers greater quality and safety assurances, makes agronomic handling easier, and allows you to know precisely which nutrients are being incorporated into the soil.

Although both are organic products, they come from different processes.

Compost is obtained through an aerobic process (requires oxygen, usually open-air), while digestate comes from anaerobic digestion (oxygen-free and completely sealed), a process that also makes it possible to produce renewable Biomethane.

The result is products with different agronomic characteristics, which can be complementary depending on the needs of each farm.

IAM Carbonzero controls the composition of feedstocks from the moment they enter the plant and applies a continuous industrial process that guarantees high product stability.

In addition, each batch is verified through analytical controls that allow its composition to be known before use.

More information about the origin of the feedstocks

Yes. Full traceability. Each batch is delivered with its corresponding technical and analytical data sheet, which records its composition and compliance with applicable regulatory requirements.

This allows the farmer to know exactly the characteristics of the product they are going to apply and to certify them.

Yes. The anaerobic digestion process (oxygen-free and completely sealed) includes operating conditions that sanitise the product, significantly reducing the presence of pathogenic microorganisms and weed seeds that may exist in the incoming feedstock.

Yes. The product complies with applicable regulations and the limits established for the required parameters, including those relating to heavy metals and other contaminants where applicable. In addition to legal compliance, IAM Carbonzero carries out quality controls that guarantee traceability and product safety.

The main value of digestate is that it helps improve soil fertility by supplying recovered nutrients and organic matter.

Its use progressively promotes soil biological activity, improves structure, increases water retention capacity and optimises nutrient uptake by crops.

These benefits become more significant when it is incorporated into an ongoing soil management and improvement strategy.

Yes, in many cases. Depending on the crop, the soil and the fertilisation plan, digestate can replace a large part of mineral fertilisation thanks to its content of recovered nutrients.

The most appropriate strategy is always defined through technical advice, seeking a balance between productivity, sustainability and soil health.

Digestate provides benefits from the first application, especially due to its nutrient content. However, its greatest value appears with continued use, as it progressively improves the physical, chemical and biological properties of the soil.

Digestate can be adapted to a wide range of crops. Its application must always be adjusted to the soil’s characteristics, the crop’s nutritional needs and the agronomic objectives of each farm. For this reason, each recommendation is made on an individual basis.

The application method depends on the type of product and the machinery available on the farm. Before each application, field conditions are assessed to ensure efficient handling compatible with normal agricultural activity.

There is no single dose. The appropriate amount to apply depends on the crop, the soil, the product composition and the planned fertilisation programme. For this reason, each application must be based on strictly agronomic criteria.

Yes. Digestate can be part of an integrated fertilisation strategy alongside other organic or mineral fertilisers. The goal is to optimise nutrient supply and progressively improve soil fertility.

IAM Carbonzero’s technical team supports farmers and partners in using the product. Our goal is for each application to meet the farm’s real needs, achieving maximum agronomic benefit from recovered nutrients.

IAM Carbonzero maintains full traceability of the product and remains the point of contact throughout the plant’s entire service life. Each batch is identified, analysed and documented, offering the farmer maximum assurance and ongoing technical support.

No. It is a product obtained through a controlled industrial process that makes it possible to recover nutrients of organic origin and return them to the soil within a circular economy model.

No. Slurry is the feedstock. Digestate is a stabilised product after anaerobic digestion, with a more homogeneous, controlled, sanitised and traceable composition.

No. The anaerobic digestion process significantly reduces the compounds responsible for odour compared to fresh slurry. In addition, it is applied following good agronomic practices to minimise any potential nuisance.

Like any fertiliser, it must be used correctly. When applied according to crop needs and fertilisation plans, digestate enables efficient nutrient use and contributes to more sustainable fertilisation management.

Yes, it is. Each batch has analytical controls and technical documentation that make it possible to know its composition precisely and guarantee traceability.

No. The goal is to recover the nutrients contained in agricultural and livestock by-products and return them to the agricultural soils of the territory they come from.

This model reduces dependence on mineral fertilisers, promotes the circular economy and turns Biomethane plants into true biorefineries capable of producing renewable energy and high agronomic-value biofertilisers.