Glossary
A natural process where microorganisms break down organic material (like crops or food waste) in the absence of oxygen, producing biogas.
Ensuring a project delivers new environmental benefits that wouldn’t have happened otherwise, such as creating new unsubsidised biogas capacity.
Baseline emissions are the greenhouse gas (GHG) emissions that would occur in a business-as-usual situation. They form the reference level against which the emissions of a project are compared in order to quantify emission increases or reductions.
Combining renewable bioenergy production with carbon capture and storage to permanently remove CO2 from the atmosphere.
The practice of growing two or more crop species simultaneously on the same field to improve yield, resource use, and biodiversity. Common examples include rye and vetch or barley and peas, where each species benefits the other through complementary nutrient or root interactions.
Broad term, that encompasses renewable energy derived from organic matter, including biomass, biogas, and biofuels.
The nutrient-rich and organic-rich material remaining after anaerobic digestion, replacing synthetic fertilisers and improving soil structure.
A renewable mixture of methane (CH4) and carbon dioxide (CO2) produced through anaerobic digestion, usable for heat, power, or upgraded to biomethane.
Carbon dioxide from biological sources such as plants, which is part of the natural carbon cycle.
Any organic matter (e.g. crops, food waste, sewage) used as a feedstock to bioenergy production.
A purified form of biogas consisting mainly of methane which has been upgraded to remove the CO2 and trace elements.
A crop planted between crops (like maize, wheat or barley) to interrupt pest and disease cycles and improve soil health.
Tradable certificates representing one tonne of CO2 avoided or removed from the atmosphere, often used in voluntary or compliance carbon markets.
The amount of greenhouse gas emitted per unit of energy generated, often expressed as kgCO2e/MWh or g CO2e/MJ
Energy generation that removes more CO₂ from the atmosphere than it emits.
The process of permanently storing captured carbon dioxide in deep geological formations, such as depleted oil and gas fields or saline aquifers, to prevent its release into the atmosphere and achieve long-term emissions reduction.
The use of captured carbon dioxide in industrial processes (e.g. carbonating drinks) or products (e.g. producing Sustainable Aviation Fuel – SAF) rather than permanent geological storage.
Broad term covering all nascent markets for captured carbon dioxide.
A carbon credit representing one tonne of atmospheric carbon which has been captured and stored permanently.
An approach that keeps materials in use for as long as possible, reducing waste and resource consumption.
A process where outputs are reused or recycled, minimising waste and emissions.
Natural gas (typically methane) that has been compressed to less than 1% of its volume at standard atmospheric pressure for use as a low-carbon vehicle fuel. When derived from biomethane, CNG becomes a renewable transport fuel that can significantly reduce greenhouse gas emissions compared to diesel, particularly in heavy goods vehicles and buses.
A crop grown primarily to protect and enrich the soil rather than for direct sale to market or consumption. Cover crops (such as clover, vetch, or mustard) are typically planted between main crops to reduce soil erosion, fix nitrogen and improve soil. Whilst not sold, cover crops can provide grazing opportunities for livestock, particularly sheep.
Growing different crops in succession on the same land to improve soil fertility and reduce vulnerability to pests and disease. Long and diverse crop rotations play a fundamental role in more sustainable farming practices.
Reducing or eliminating carbon dioxide emissions.
Energy generation that can be turned on or off to meet demand; biogas provides this flexibility unlike intermittent renewables.
Farmers introducing new revenue streams like energy crops or feedstock supply to support farm resilience.
The total CO2 emitted during the production and transport of materials before they are used.
A value used to estimate emissions per unit of activity (e.g. kgCO2e per kWh of gas burned).
Ensuring reliable, affordable, and sustainable access to energy resources domestically.
The regulatory process required to build and operate waste-fed anaerobic digestion or carbon capture sites safely and legally.
The European Union’s carbon pricing mechanism, setting a cap on total greenhouse gas emissions from covered sectors and allowing trading of emission allowances.
Organic materials such as crops or residues used in anaerobic digestion to produce biogas.
Non-renewable natural gas extracted from underground reserves; its extraction, transmission and use directly results in GHG emissions. Biomethane is a renewable drop-in replacement to fossil gas.
Unintentional releases of gases like methane from equipment or pipelines.
Gases like carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) that trap heat in the atmosphere and contribute to climate change.
Renewable gas such as biomethane produced from sustainable organic sources rather than fossil sources.
The process of introducing biomethane into the gas grid for national distribution.
When a company reduces or removes emissions within its own value chain, rather than offsetting through unrelated projects.
A certification verifying sustainable production, traceability, and emission reduction across supply chains.
Biomethane cooled to liquid form for easier transport and storage, often used in heavy goods vehicles.
A comprehensive evaluation of environmental impacts throughout a product or process’s entire life cycle.
A fuel that emits significantly less CO2 than fossil alternatives over its life cycle, such as biomethane.
The primary component of biogas/biomethane and natural gas.
A process where CO2 is chemically bound into solid materials like concrete for permanent storage.
The process of accurately tracking and independently confirming emission reductions or removals for certification.
Achieving a balance between greenhouse gas emissions produced and removed from the atmosphere. If a country becomes Net Zero, it is no longer contributing to global GHG emissions.
A greenhouse gas with 298 times the warming potential of CO2, often emitted from fertiliser use – reduced through management/limiting artificial fertiliser applications, good agricultural practices and displacing artificial fertiliser with digestate.
Returning nutrients in organic materials like digestate back to soils to maintain soil fertility.
The regulatory process required to build and operate waste-fed anaerobic digestion or carbon capture sites safely and legally.
The natural process by which plants convert sunlight, water, and carbon dioxide into oxygen and biomass, forming the basis of biogenic carbon.
A contract under which a buyer agrees to purchase renewable power or gas at an agreed price over a set period.
A holistic system of agricultural management that actively rebuilds and enhances soil health, biodiversity, water-retention and ecosystem resilience. It involves farming practices tailored to each site (soil, climate and enterprise), minimising soil disturbance, keeping the soil covered and roots alive, maximising diversity of plants and animals, and integrating livestock or equivalent functions, aiming to restore degraded soils and support long-term productivity.
Agricultural by-products such as straw which may be used as a feedstock for AD.
Certificates verifying that biomethane injected into the gas grid is produced from renewable sources.
A low-carbon, drop-in alternative to conventional jet fuel made from sustainable, non-fossil feedstocks. SAF reduces life-cycle emissions and can be used in existing aircraft and fuel infrastructure.
Categories of a company’s emissions: direct (Scope 1), indirect from purchased energy (Scope 2), and value-chain-related (Scope 3).
Long-term storage of carbon in soils, plants, or geological formations to mitigate climate change.
Organic carbon accumulated and stored in soil that contributes to fertility, structure, and climate stability.
Meeting present needs without compromising the ability of future generations to meet theirs.
A standard unit for comparing greenhouse gases based on their global warming potential relative to CO2.
The preparation of soil for planting crops; reduced or minimal tillage results in lower soil disturbance and therefore helps preserve soil carbon and structure.
The extent to which feedstocks and products can be tracked back through the entire supply chain for transparency and accountability.
A cap-and-trade system established by the United Kingdom government to limit greenhouse gas emissions across energy-intensive industries, the power sector, and aviation. Companies receive or purchase allowances for each tonne of CO2e emitted, incentivising decarbonisation and investment in low-carbon technologies.
A secondary crop sown beneath a standing main crop, designed to establish before the main crop is harvested. Once the main crop is removed, the undersown crop continues to grow, providing soil cover, nutrient retention, or livestock forage.