Frequently Asked
Questions
Straightforward answers about biomethane, safety, regulations, and how to get involved.
Biomethane is a clean, renewable gas made by breaking down organic materials such as animal slurry, grass silage, and food waste in a sealed tank. It works just like natural gas but comes from local, biodegradable sources rather than fossil fuels.
Biogas is the raw gas created during anaerobic digestion, containing methane, carbon dioxide, and small impurities. Biomethane is the upgraded form of this gas, where carbon dioxide and impurities are removed. The result is a clean, renewable gas with the same quality as natural gas, ready for use in the gas grid, heating, transport, or electricity.
Biomethane is still at an early stage in Ireland but is already being produced and injected into the gas grid on a small scale. The Government's National Biomethane Strategy sets out plans for rapid growth, aiming for widespread use across the country in the coming years.
The other 3% typically consists of small amounts of impurities:
- Carbon Dioxide (CO₂): A small percentage may remain after the upgrading process.
- Nitrogen: Sometimes present, especially if air has been used in production.
- Hydrogen Sulfide (H₂S): A trace amount, usually removed during upgrading.
- Oxygen: A small amount depending on the production method.
- Water Vapour: Depending on the process, a small amount may remain.
Yes. Biomethane can be carbon negative, meaning it removes or prevents more greenhouse gases than it produces. Cattle slurry emits methane when decomposed, but by digesting it in a closed tank, biomethane is produced instead — releasing CO₂, which has a much lower global warming potential than raw methane. Similarly, using food waste prevents methane emissions from landfills. The CO₂ separated during production can be captured and stored, contributing further to negative emissions.
According to Gas Networks Ireland's Biomethane Energy Report (September 2023), Ireland has the potential for 14.8 TWh/year of biomethane production — 2.6 times the 2030 target of 5.7 TWh. This means up to 26% of Ireland's current natural gas demand could be replaced and decarbonised by biomethane, delivering a significant boost to the rural economy while reducing reliance on natural gas imports.
Yes. Biomethane plants are widely used across Europe and are designed to meet strict safety and environmental standards. They are carefully regulated and monitored to ensure safe operation and minimal impact on neighbours.
After digestion, the leftover material — called digestate — is nutrient-rich and can be used as a natural fertiliser on farmland. This helps reduce the need for chemical fertilisers and supports sustainable farming.
When managed properly, biomethane plants are designed to control odours and emissions. Feedstocks are stored and handled in sealed tanks, and the process reduces methane emissions compared to leaving slurry or waste untreated.
Yes, methane is flammable — similar to natural gas, oil, or petrol — but biomethane plants are designed with strict safety measures to prevent accidents. The gas is pressurised like natural gas already used across Ireland, and advanced engineering ensures safe operation. In case of malfunction or pressure surge, safety flares burn off excess gas to reduce explosion risk. These protocols are in place to ensure safety for local communities and workers.
Methane leaks can potentially contribute to emissions, but modern plants are designed with strict safety measures to prevent them. Equipment for production, storage, and transport is carefully engineered to minimise escape of methane into the atmosphere. Any accidentally released methane is typically captured and burned off in safety flares.
Plants and trucks are designed to minimise odours. Feedstocks like slurry and crop waste can have a natural smell, but modern plants use closed systems for digestion which significantly reduces odour emissions. Collection trucks use covered containers to limit smells during transport. Any potential impact on local areas is minimised through proper management practices.
Biomethane must emit at least 80% fewer greenhouse gases than the fossil fuel it replaces, per EU renewable energy directives. This helps minimise climate change impacts on biodiversity. Locally, using anaerobic digestate instead of synthetic fertiliser and slurry reduces waterway pollution from run-offs.
It is important to prevent digestate runoff into waterways, but since digestate is usually pasteurised, it poses less risk to water quality than synthetic fertilisers. A well-operated AD system minimises nutrient remnants, and nitrogen-rich feedstocks like manures yield digestate high in ammonium — which plants absorb easily — reducing the risk of runoff and nitrification of waterways.
The CO₂ can be captured and stored or used in various industries through Carbon Capture, Utilisation, and Storage (CCUS). It can be converted into chemicals, fuels, and building materials, or used directly in refrigeration, biomass production (algae), and food and beverage industries as a carbonating agent. CO₂ can also be stored underground in carbon sequestration systems, or combined with hydrogen to produce e-methanol, ethanol, or sustainable aviation fuel (SAF).
Biomethane from agricultural feedstocks is generally very clean. Impurities such as hydrogen sulfide (H₂S) may be present in the raw biogas, but these are removed before the gas is upgraded. The final product injected into the grid is high quality and safe for use. Regular monitoring and filtering systems ensure compliance with stringent safety and quality standards.
Food waste and crops can attract vermin, but careful management of feedstock stores and pest control at plants can prevent infestations. The processing of feedstocks in anaerobic digestion also makes them less attractive to vermin.
Common feedstocks include animal slurry, grass silage, crop residues, and food waste. These materials are abundant in Ireland and help recycle nutrients back to the soil after digestion.
Yes. Farmers can provide slurry, silage, and other residues to biomethane plants and receive payment, creating a new and stable income stream alongside traditional farming activities.
No. Biomethane development in Ireland will prioritise farm residues, manures, and grass — not food crops. The aim is to complement food production, not compete with it, while also returning digestate to farmers as fertiliser.
No. Ireland's biomethane strategy prioritises waste (bioresources) not crops — mainly slurry, manure, straw, food waste, and farm residues — so food production land remains unchanged. Farmers can grow extra grass silage for AD without reducing food production. By using farm and food waste, AD helps reduce emissions, improve nutrient recycling, and lower reliance on chemical fertilisers.
During summer, when slurry availability is low due to livestock grazing, AD plants will rely more on grass silage stored in advance. Some developers may build large slurry storage tanks to retain supplies from winter and spring. Alternative feedstocks like crop residues, poultry manure, and food by-products may also be used. Farmers should plan ahead and coordinate with AD plants to ensure a steady year-round supply.
Building a biomethane plant is a major investment — equipment alone costs around €3 million, with total plant setup exceeding €15 million. To be competitive with fossil gas, plants need to operate near full capacity year-round, processing large amounts of feedstock consistently. Most plants aim to produce around 40 GWh of biomethane per year, requiring up to 100 farms to supply the right amount and variety of materials. The more farmers involved, the more stable and reliable the feedstock supply.
Yes. Like any significant development, biomethane plants must go through the full planning permission process. This includes environmental assessments and community consultation.
Biomethane plants must comply with Irish and EU safety, environmental, and energy regulations. Local authorities oversee planning and environmental permits, while agencies such as the Environmental Protection Agency (EPA) and Commission for Regulation of Utilities (CRU) regulate operations and grid connections.
Yes. Plants must follow strict environmental standards covering feedstock use, waste management, emissions, and nutrient recycling. These safeguards ensure protection of air, water, soil, and biodiversity, enforced through planning and licensing conditions.
No specific minimum distances have been set. Plants will typically be located in the countryside, and decisions to grant planning permission will consider proximity to houses in the overall suitability assessment of each project.
Digestate is subject to Ireland's Nitrates Directive, similar to slurry. There are closed periods when spreading is not allowed — typically mid-October to mid-January, depending on location.
Water used in an anaerobic digestion system can be reused, eliminating disposal needs. This sustainable approach may require EPA wastewater licences depending on feedstocks. Waste undergoes rigorous testing to prevent environmental impacts. Slurries stored on-site are contained in impermeable tanks, and areas around digesters are enclosed in concrete with raised bunds to prevent feedstock runoff and groundwater contamination.
- Reduce emissions: Biomethane cuts greenhouse gas emissions by over 80% compared to fossil gas.
- Extra income: Supply feedstocks like slurry and crops for additional, stable income.
- Solve slurry issues: Biomethane production helps manage slurry and reduces fertiliser costs with nutrient-rich digestate.
- Meet national targets: Ireland has strict emission reduction targets; biomethane helps agriculture avoid penalties.
- Sustainability: Decarbonising beef and dairy sectors ensures long-term viability and aligns with national goals.
- Long-term contracts: Secure 10–20 year agreements with developers, offering stability and easing succession planning.
- Renewable fuel: Biomethane is space-efficient and less visible than solar or wind infrastructure.
Yes, farmers can earn substantial income from supplying feedstocks to AD plants:
- Payments vary by contract: Generally, farmers earn money for supplying grass, crops, slurry, or food waste — exact amounts depend on contract terms.
- Digestate as part of the deal: Some developers offer digestate in exchange for slurry, reducing fertiliser costs significantly.
- Consistent supply = higher payments: Year-round supply earns better rates than seasonal supply.
- SEAI estimates: By 2050, grass silage prices could increase by 20%, reaching around €36/tonne. Food waste prices could drop from €50 to €40/tonne, potentially making supply more profitable.
- Co-ownership potential: Some farmers may partner with AD plants through profit-sharing or co-ownership models.
It can be, depending on key factors:
- Long-term contracts provide stability: Most AD developers want 10–20 year supply contracts, providing predictable income for feedstocks like silage, slurry, or food waste.
- Feedstock type matters: High-energy crops like silage generally earn more than lower-energy materials like slurry.
- Market conditions may change: While contracts offer security, prices can still be influenced by demand, policy, and market changes. A well-negotiated contract helps protect against price drops.
Bottom line: A feedstock contract can provide reliable income, but it's important to understand the terms and negotiate a good price.
Digestate can help reduce slurry storage needs in several ways:
- Easier to manage: Digestate can be separated into liquid and solid. The solid part takes up less space and can be stored separately or sold as fertiliser.
- Can be spread more often: Digestate smells less and has readily available nutrients, allowing more frequent application and reducing storage needs.
- May help with regulations: If using a digester, you might not need to build as much extra storage, which saves money.
Yes — and in many ways it can be even better:
- Keeps nutrients on the farm: Digestate contains nitrogen (N), phosphorus (P), and potassium (K) in a form crops can absorb more easily than raw slurry.
- Reduces need for synthetic fertiliser: Key nutrients are already present, leading to cost savings and better soil health.
- Helps with nitrogen limits: Digestate contains more plant-available nitrogen than raw slurry, allowing more efficient use within regulations.
- Better for spreading: Fewer odours and compatible with low-emission spreading techniques.
- Improves soil health: Adds organic matter, improving structure, water retention, and microbial activity.
No, digestate is safe when properly processed:
- Pasteurisation: Digestate from multiple farms is typically heated to 70°C for 1 hour to kill harmful pathogens.
- Bord Bia approval: After pasteurisation, Bord Bia approves digestate for use (as long as it does not come from sewage or sewage sludge).
- Farm-based digestate: Digestate from farm-based AD systems fed with crops is safe and can be applied directly to land as a fertiliser.
Generally, methane-producing microbes are deactivated in aerobic (oxygen-containing) environments. However, digestate can emit methane if microbes remain active and the material is not properly managed or stored. To prevent this, digestate should be dried or composted, which stops microbial activity and reduces methane risk — while also making it more valuable as a fertiliser or soil conditioner.
It depends on the agreement with the AD plant developer. Some developers may store and manage digestate on-site, while others may require farmers to have on-farm storage. Farmers using digestate as fertiliser will likely need sufficient storage to comply with slurry storage regulations.
This varies by project. Some AD developers provide storage and deliver digestate when needed, while others may require farmers to collect and store it themselves. Check the agreement details to understand who is responsible for storage and logistics.
Biomethane plants need a steady feedstock supply to operate at full capacity:
- Incentives for summer slurry: Developers may offer premium payments to encourage slurry provision during summer months.
- No requirement to house cattle year-round: While incentives may be offered, year-round housing is not required. Balancing indoor and outdoor grazing with feedstock supply is key.
- Alternative feedstocks: Grass silage and crop residues can help meet summer demand if full-time housing isn't suitable for your operation.
Yes. Even if hydrogen becomes more common, biomethane will remain important:
- Grid compatibility: Biomethane can fully replace natural gas in pipelines — the existing network can handle some hydrogen, but not full replacement.
- Complementary technologies: Biomethane and hydrogen can work together. E-methane (made by combining H₂ with CO₂) can be produced, meaning they complement rather than replace each other.
- Stable farmer income: Biomethane is also used in high-temperature industrial heating and heavy vehicle fuel — creating steady long-term demand for farm feedstocks.
Denmark is a global leader in biomethane, with roughly 40% of its gas supply coming from biomethane and around 150 biogas plants operating:
- Agriculture-based feedstocks: Heavy reliance on animal slurry and manure reduces farm emissions and creates farmer revenue.
- Farmer-led cooperatives: Farmers own and supply plants with agricultural waste, benefiting directly from production.
- Large, centralised plants: Scale lowers costs and increases efficiency compared to many small plants.
- Strong government support: Long-term policies, subsidies, and stable prices encourage investment and participation.
- Diverse feedstocks: Food waste, crop residues, and energy crops supplement livestock waste.
Biomethane plants run 24/7 all year round. Anaerobic digestion works continuously to break down organic material. Day-to-day operations involve regular monitoring, daily feeding of the digester, and routine maintenance. Most plants have automated systems, but staff are needed for monitoring and occasional adjustments. Feedstock delivery will have set times, but biomethane production itself never stops.
Yes. Feedstocks are typically delivered daily to biomethane plants by heavy goods vehicles (HGVs) — not tractors — while digestate is also collected by HGV. Wheel washes are used at plants to prevent dirt on roads. Traffic management plans are required during the planning process. Feedstocks are typically sourced from within 10 km of the plant to minimise transportation distances and fuel use.
Biomethane plants are typically clean industrial areas with no mud, and will often require wheel wash facilities. Feedstock collections and digestate deliveries are expected to be by HGVs rather than tractors, and must take place in clean areas on farms.
Site selection is based on several key factors:
- Close to feedstock supply: Near farms and food processing units to reduce transport costs.
- Near gas pipelines: Proximity to the national gas network makes injection easier and cheaper.
- Good road access: Wide roads for HGVs delivering feedstock and transporting digestate.
- Suitable land conditions: Flat, stable sites preferred for construction and operations.
- Minimal neighbour impact: Typically placed in rural or industrial areas to avoid odour complaints and heavy traffic near homes.
Typically very little. Anaerobic digestors are silent, only requiring stirring. Pumps and compressors will operate and some vehicle movement will occur on site. Soundproofing measures are put in place to minimise noise impacts on the surrounding area.
- New income for farmers: Earn by supplying slurry, manure, and other organic materials. Some may also receive digestate in return.
- Job creation: Plants create local jobs in construction, operation, and maintenance.
- Better waste management: Animal slurry and food waste become valuable energy instead of decomposing and releasing methane.
- Cleaner air and water: Reduced farm emissions, less odour, and prevention of slurry runoff into waterways.
- Reliable local energy: Gas produced can power homes, businesses, and transport.
- Rural development: Investment in infrastructure such as roads and transport links.
The quantity of water required by plants is typically relatively small and not considered an issue, as most water can be recycled in the anaerobic digestion process. Quantities will vary between projects and should be considered by the local authority during the planning process.
Yes. The regulatory landscape for biomethane covers eight main thematic areas:
- Planning Consent: Planning Permission, EIAR, AA/NIS, Flood Risk Assessment, Fire Safety, Disability Access Certificate.
- Environmental / Emissions: EPA IE Licence, Air Pollution Act, Section 4 and Section 16 licences, Water Abstraction, Noise (EPA AG9), Odour.
- Traffic & Roads: TII Traffic Assessment, Road Opening Licence, Abnormal Load Permit, ADR, Temporary Traffic Management, Bridge Clearance Checks.
- Utilities & Energy: ESB Networks Demand Connection, ESBN/EirGrid Generator Connection, GNI Biomethane Injection, CRU Gas Act s.39A Consent.
- Materials, Waste & ABP: EU Reg. 1069/2009 (ABP), EU Reg. 142/2011, Nitrates Regulations, C&D Waste Management Plan.
- Biodiversity & Heritage: Habitats Directive (AA/NIS), Birds Directive, EIA Directive, National Monuments Acts, Landscape & Visual Assessment.
- Health, Safety & Construction: Safety, Health & Welfare (Const.) Regs 2013, ATEX 2014/34/EU, Pressure Systems (GA Regs 2007), Dangerous Substances Licence, COMAH/Seveso, HSA Notification.
- Site-Specific & Other: Weighbridge Cert, MCP Registration, Building Regulations, BCMS, Commencement Notice, other Local Authority Permits.
The end-to-end permitting and planning roadmap has six stages:
- Feasibility & Site: Desktop scan of zoning, Natura 2000, flood, heritage, and grid capacity. Land control (options/HoT).
- Pre-Planning & Scoping: Formal pre-planning, EIA/AA screening, surveys (ecology, noise, odour), and confirming the licence path (EPA IE/ABP).
- Planning Application: Full planning set — plans, EIAR (if required), AA/NIS, Traffic, Noise & Odour, Flood Risk, CMP, Heritage.
- Parallel Consents: EPA IE licence (if thresholds met), Section 4/16 discharge, Road Opening Licences, GNI/ESB connections, COMAH screening.
- Construction Mobilisation: Appoint PSDP/PSCS, Construction Management Plan, Traffic Management (TII), HSA notification, C&D Waste Plan.
- Commissioning & Operations: Grid and gas commissioning, odour/flare checks, safety file, staff training, complaints protocol, ongoing monitoring.
Biomethane production currently costs more than natural gas, so it is primarily purchased by large companies willing to pay a 'green premium' to reduce their carbon footprint. As the sector evolves, production costs are expected to decrease. Gas utilities and transport fuel companies are likely to be key buyers. The government is also expected to introduce a Renewable Heat Obligation (RHO), requiring gas suppliers to blend a minimum percentage of renewable gas into their supply — targeting 10% by 2030.
Biomethane plants create local jobs and profits, boosting the rural economy, and typically include community funds. Where profits go depends on the developer. The Biomethane for Carbon and Community project is researching co-operative ownership models, which would mean revenues stay in the Irish economy instead of being spent on fuel imports.
The National Biomethane Strategy estimates that constructing and operating AD plants in Ireland could generate around 2,700 jobs in the rural economy. For a standard 40 GWh plant, this translates to approximately 13 direct jobs and 31 indirect jobs, covering roles such as plant operators, management teams, and construction workers. The Biomethane Implementation Group is developing training programmes to prepare the workforce.
Yes, if designed properly. Many European plants operate profitably without subsidies, and Ireland has the potential for similar success. The Irish government has allocated capital grants to 18 biomethane projects, and the upcoming Renewable Heat Obligation (RHO) will create a stable market for biomethane. However, addressing challenges from cheap imports and fraudulent practices is important to ensure a fair ecosystem for local developers.
A nearby biomethane plant is unlikely to impact property values. Plants typically occupy about 10 acres for a 40 GWh capacity and consist of tanks, shed-like buildings, and an office. Landscaping with trees and hedgerows is common to reduce visibility. Vibrations, noise, and odours are expected to be minimal, as plants use odour treatment units. Steam and smoke emissions are not expected, and biogas flares are only activated at high pressures. Wheel washes will minimise dirt on roads from increased HGV traffic.