Biogas - Biogas production, conditioning, upgrading and utilization - Terms, definitions and classification scheme (ISO 20675:2018)

This document defines terms and describes classifications related to biogas production by anaerobic digestion, gasification from biomass and power to gas from biomass sources, biogas conditioning, biogas upgrading and biogas utilization from a safety, environmental, performance and functionality perspective, during the design, manufacturing, installation, construction, testing, commissioning, acceptance, operation, regular inspection and maintenance phases.
Biogas installations are, among others, applied at industrial plants like food and beverage industries, waste water treatment plants, waste plants, landfill sites, small scale plants next to agricultural companies and small scale household installations.
The following topics are excluded from this document:
—   boilers, burners, furnaces and lightening, in case these are not specifically applied for locally produced biogas;
—   gas-fuelled engines for vehicles and ships;
—   the public gas grid;
—   specifications to determine biomethane quality;
—   transportation of compressed or liquefied biogas;
—   transportation of biomass or digestate;
—   assessment and determination whether biomass is sourced sustainably or not.
This document describes the following for information purposes as well:
—   the parameters to determine the size (e.g. small, medium-sized, or large scale);
—   the parameters to determine the type of installation (e.g. domestic, industrial);
—   the parameters to describe the type of technique;
—   terms and processes in order to develop health, safety and environmental protection guidelines for biogas installations.
NOTE   For an explanation of the Scope, see Annex A.

Biogas - Erzeugung, Aufbereitung, Konditionierung und Verwendung von Biogas - Begriffe, Definitionen und Klassifizierungsschema (ISO 20675:2018)

Biogaz - Production, traitement, épuration et utilisation du biogaz - Termes, définitions et classification(ISO 20675:2018)

Bioplin - Proizvodnja, priprava, nadgradnja in uporaba bioplina - Izrazi, definicije in shema razvrščanja (ISO 20675:2018)

Ta dokument opredeljuje izraze in opisuje klasifikacije, povezane s proizvodnjo bioplina z anaerobno presnovo, uplinjanjem iz biomase in energije v plin iz virov biomase, pripravo bioplina, nadgradnjo bioplina in uporabo bioplina z vidika varnosti, okolja, učinkovitosti ter funkcionalnosti, med projektiranjem, proizvodnjo, montažo, konstrukcijo, testiranjem, zagonom, prevzemom, obratovanjem, rednimi pregledi in vzdrževanjem.
Naprave za bioplin se med drugim uporabljajo v industrijskih obratih, kot so živilska industrija in industrija pijač, čistilne naprave, obrati za predelavo odpadkov, odlagališča, manjši obrati ob kmetijskih podjetjih ter manjše naprave v gospodinjstvih.
Naslednje teme niso vključene v ta dokument:
–   kotli, gorilniki, peči in razsvetljava, če se ne uporabljajo posebej za lokalno proizvodnjo bioplina;
–   plinski motorji za vozila in ladje;
–   javno plinsko omrežje;
–   specifikacije za določitev kakovosti biometana;
–   transport stisnjenega ali utekočinjenega bioplina;
–   transport biomase ali digestata;
–   ocena in ugotavljanje, ali je biomasa pridobljena trajnostno ali ne.
Teme, ki jih ta dokument vsebuje v informativne namene:
–   parametri za določitev velikosti (npr. majhna, srednja ali velika);
–   parametri za določitev vrste naprave (npr. gospodinjska, industrijska);
–   parametri za opis vrste tehnike;
–   pogoji in postopki za razvoj smernic za zdravje, varnost in varstvo okolja pri uporabi bioplinskih naprav.
OPOMBA:   Za razlago področja uporabe glej dodatek A.

General Information

Status
Published
Public Enquiry End Date
01-Oct-2021
Publication Date
12-Jan-2022
Technical Committee
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
21-Dec-2021
Due Date
25-Feb-2022
Completion Date
13-Jan-2022

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SLOVENSKI STANDARD
SIST EN ISO 20675:2022
01-februar-2022

Bioplin - Proizvodnja, priprava, nadgradnja in uporaba bioplina - Izrazi, definicije in

shema razvrščanja (ISO 20675:2018)

Biogas - Biogas production, conditioning, upgrading and utilization - Terms, definitions

and classification scheme (ISO 20675:2018)
Biogas - Erzeugung, Aufbereitung, Konditionierung und Verwendung von Biogas -
Begriffe, Definitionen und Klassifizierungsschema (ISO 20675:2018)

Biogaz - Production, traitement, épuration et utilisation du biogaz - Termes, définitions et

classification(ISO 20675:2018)
Ta slovenski standard je istoveten z: EN ISO 20675:2021
ICS:
01.040.75 Naftna in sorodna tehnologija Petroleum and related
(Slovarji) technologies (Vocabularies)
75.160.40 Biogoriva Biofuels
SIST EN ISO 20675:2022 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN ISO 20675:2022
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SIST EN ISO 20675:2022
EN ISO 20675
EUROPEAN STANDARD
NORME EUROPÉENNE
December 2021
EUROPÄISCHE NORM
ICS 75.020; 27.190
English Version
Biogas - Biogas production, conditioning, upgrading and
utilization - Terms, definitions and classification scheme
(ISO 20675:2018)
Biogaz - Production, traitement, épuration et utilisation (ISO 20675:2018)
du biogaz - Termes, définitions et classification(ISO
20675:2018)
This European Standard was approved by CEN on 29 November 2021.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this

European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references

concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN

member.

This European Standard exists in three official versions (English, French, German). A version in any other language made by

translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management

Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,

Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,

Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and

United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels

© 2021 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 20675:2021 E

worldwide for CEN national Members.
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SIST EN ISO 20675:2022
EN ISO 20675:2021 (E)
Contents Page

European foreword ....................................................................................................................................................... 3

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SIST EN ISO 20675:2022
EN ISO 20675:2021 (E)
European foreword

The text of ISO 20675:2018 has been prepared by Technical Committee ISO/TC 255 "Biogas” of the

International Organization for Standardization (ISO) and has been taken over as EN ISO 20675:2021 by

Technical Committee CEN/TC 408 “Natural gas and biomethane for use in transport and biomethane for

injection in the natural gas grid” the secretariat of which is held by AFNOR.

This European Standard shall be given the status of a national standard, either by publication of an

identical text or by endorsement, at the latest by June 2022, and conflicting national standards shall be

withdrawn at the latest by June 2022.

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. CEN shall not be held responsible for identifying any or all such patent rights.

Any feedback and questions on this document should be directed to the users’ national standards body.

A complete listing of these bodies can be found on the CEN website.

According to the CEN-CENELEC Internal Regulations, the national standards organizations of the

following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,

Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,

Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of

North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the

United Kingdom.
Endorsement notice

The text of ISO 20675:2018 has been approved by CEN as EN ISO 20675:2021 without any modification.

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SIST EN ISO 20675:2022
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SIST EN ISO 20675:2022
INTERNATIONAL ISO
STANDARD 20675
First edition
2018-02
Biogas — Biogas production,
conditioning, upgrading and
utilization — Terms, definitions and
classification scheme
Biogaz — Production, traitement, épuration et utilisation du biogaz
— Termes, définitions et classification
Reference number
ISO 20675:2018(E)
ISO 2018
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SIST EN ISO 20675:2022
ISO 20675:2018(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2018

All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may

be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting

on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address

below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva, Switzerland
Tel. +41 22 749 01 11
Fax +41 22 749 09 47
copyright@iso.org
www.iso.org
Published in Switzerland
ii © ISO 2018 – All rights reserved
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SIST EN ISO 20675:2022
ISO 20675:2018(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................iv

Introduction ..................................................................................................................................................................................................................................v

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms and definitions ..................................................................................................................................................................................... 2

4 Abbreviated terms .............................................................................................................................................................................................. 9

5 Classifications .......................................................................................................................................................................................................10

Annex A (informative) Explanation to the scope ..................................................................................................................................11

Annex B (informative) Biogas characteristics, processes and classifications ........................................................15

Bibliography .............................................................................................................................................................................................................................20

© ISO 2018 – All rights reserved iii
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SIST EN ISO 20675:2022
ISO 20675:2018(E)
Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national standards

bodies (ISO member bodies). The work of preparing International Standards is normally carried out

through ISO technical committees. Each member body interested in a subject for which a technical

committee has been established has the right to be represented on that committee. International

organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.

ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of

electrotechnical standardization.

The procedures used to develop this document and those intended for its further maintenance are

described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the

different types of ISO documents should be noted. This document was drafted in accordance with the

editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of

any patent rights identified during the development of the document will be in the Introduction and/or

on the ISO list of patent declarations received (see www .iso .org/ patents).

Any trade name used in this document is information given for the convenience of users and does not

constitute an endorsement.

For an explanation on the voluntary nature of standards, the meaning of ISO specific terms and

expressions related to conformity assessment, as well as information about ISO's adherence to the

World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see the following

URL: www .iso .org/ iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 255, Biogas.
iv © ISO 2018 – All rights reserved
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SIST EN ISO 20675:2022
ISO 20675:2018(E)
Introduction

The technical committee on biogas (ISO/TC 255) was established in 2011 in order to

— provide liberalization and facilitation for international trade of biogas installations,

— contribute to international cooperation on technical regulations, standards and assessment

procedures,

— curb discriminatory technical requirements as the main form of trade protectionism, and

— reduce and eliminate the technical barriers for international trade of biogas installations.

This document about terms, definitions and classifications is applicable for biogas production by

anaerobic digestion, gasification from biomass and power to gas from biomass sources, biogas

conditioning, biogas upgrading and biogas utilization.

The availability of a set of agreed terms and definitions for biogas installations, as well as a classification

scheme for the whole biogas chain, is necessary in order to

— moderate the communication between the different biogas parties through meaningful discussions,

— facilitate development of regional and national regulations and incentive programs to promote

biogas production and application,

— contribute to the reinforcement of biogas installations’ safety and business competitiveness with

recognized terms and definitions that clarify the actors’ expectations related to procurement,

contracts and services as well as reporting on biogas related action plans and road maps, and

— contribute to the use of standards by facilitating their development and furthering the users’

understanding and application of standards.

ISO/TC 255 intends to promote international technology exchange and to accelerate international

application of biogas (products) and equipment by developing and maintaining globally harmonized

standards.
© ISO 2018 – All rights reserved v
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SIST EN ISO 20675:2022
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SIST EN ISO 20675:2022
INTERNATIONAL STANDARD ISO 20675:2018(E)
Biogas — Biogas production, conditioning, upgrading and
utilization — Terms, definitions and classification scheme
1 Scope

This document defines terms and describes classifications related to biogas production by anaerobic

digestion, gasification from biomass and power to gas from biomass sources, biogas conditioning,

biogas upgrading and biogas utilization from a safety, environmental, performance and functionality

perspective, during the design, manufacturing, installation, construction, testing, commissioning,

acceptance, operation, regular inspection and maintenance phases.

Biogas installations are, among others, applied at industrial plants like food and beverage industries,

waste water treatment plants, waste plants, landfill sites, small scale plants next to agricultural

companies and small scale household installations.
The following topics are excluded from this document:

— boilers, burners, furnaces and lightening, in case these are not specifically applied for locally

produced biogas;
— gas-fuelled engines for vehicles and ships;
— the public gas grid;
— specifications to determine biomethane quality;
— transportation of compressed or liquefied biogas;
— transportation of biomass or digestate;
— assessment and determination whether biomass is sourced sustainably or not.
This document describes the following for information purposes as well:

— the parameters to determine the size (e.g. small, medium-sized, or large scale);

— the parameters to determine the type of installation (e.g. domestic, industrial);

— the parameters to describe the type of technique;

— terms and processes in order to develop health, safety and environmental protection guidelines for

biogas installations.
NOTE For an explanation of the Scope, see Annex A.
2 Normative references
There are no normative references in this document.
© ISO 2018 – All rights reserved 1
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SIST EN ISO 20675:2022
ISO 20675:2018(E)
3 Terms and definitions
For the purpose of this document, the following terms and definitions apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
anaerobic digestion

biological conversion of biodegradable materials by micro-organisms in the absence of oxygen creating

two main products: biogas (3.2) and digestate (3.19)

Note 1 to entry: An example of anaerobic digestion is the biological conversion of the biodegradable parts of

biomass (3.9) sources, but also fossil biodegradable sources.
Note 2 to entry: Wet and dry anaerobic digestion systems are applied.
3.2
biogas

gas produced by anaerobic digestion of organic matter, gasification (3.25) of biomass (3.9) or power to

gas from biomass sources and without further upgrading or purification

Note 1 to entry: Biogas comprises mainly methane and carbon dioxide and/or hydrogen and/or carbon monoxide

and/or heavier hydrocarbons with two till six carbon atoms.
Note 2 to entry: Bio-syngas (3.15) is also a type of biogas.
3.3
biogas boiler
boiler which uses biogas (3.2) as fuel
3.4
biogas flare
installation to burn biogas (3.2), whether superfluous or not

Note 1 to entry: A flare is applied for biogas generated in biogas installations (3.5) or extracted from landfill sites,

among others, to avoid methane and/or hazardous compounds to be emitted into the atmosphere. A biogas flare

can be applied as safety, environmental and/or process device.

Note 2 to entry: A typical flare consists of, among others, an ignition system, flame and temperature detection

system, windproof body and combustion chamber, biogas piping, valves, condensate drainage, electrical control

cabinet, installation fixtures, burner head, heat insulation and pilot or ignition burner.

Note 3 to entry: A flare can be classified in three main categories: open flare (3.43), enclosed flare (3.23) and

enclosed high efficiency flare (3.24).
3.5
biogas installation

installation including its pipelines, pipes and accessories for anaerobic digestion of biomass (3.9),

gasification (3.25) of biomass and waste, upgrading of biogas (3.2), liquefaction of biogas, storage of biogas

(in raw, gas or liquid form), storage of CO , storage of auxiliaries, storage of biomass and digestate (3.19)

Note 1 to entry: Upgrading of biogas includes cooling, compressing, heating, separation, reaction in order to

purify or upgrade the biogas to a higher methane percentage.
2 © ISO 2018 – All rights reserved
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SIST EN ISO 20675:2022
ISO 20675:2018(E)
3.6
biogas pipeline

system of pipework for transportation of biogas (3.2) or biomethane (3.12) with all associated equipment

and stations up to the point of delivery and outside the biogas installation (3.5)

Note 1 to entry: This pipework is mainly below ground, but includes also above-ground parts.

3.7
biogas storage
buffer, gas holder, tank, vessel, bag or similar to store biogas (3.2)
Note 1 to entry: The biogas storage can be part of the fermenter.
3.8
biogenic content
organic material from biomass (3.9)
3.9
biomass

material of biological origin excluding material embedded in geological formations and/or transformed

to fossilized material

Note 1 to entry: Biomass is organic material that is plant-based or animal-based, including, but not limited to

dedicated energy crops, agricultural crops and trees, food, feed and fibre crop residues, aquatic plants, alga,

forestry and wood residues, organic agricultural, animal and processing by-products, agricultural, municipal

and industrial organic waste and residues whether or not in landfills, sludge, waste water, and other non-fossil

organic matter.
3.10
biomass pipeline
digestate pipeline

system of pipework for transportation of liquid biomass (3.9) or digestate (3.19) with all associated

equipment and up to the point of delivery
3.11
biomass pretreatment

treatment of biomass (3.9) with chemical, physical, thermal and biological methods in order to increase

methane production when the biomass is digested or gasified
3.12
biomethane

methane-rich gas with the properties similar to natural gas derived from biogas (3.2) produced by

anaerobic digestion or gasification (3.25) or from power to gas by upgrading

Note 1 to entry: Requirements for chemical and physical properties of biomethane, such as heat content, flame

characteristics, dew points, traces of chemical compounds, are part of standards for injection of biomethane in

public grids and standards for vehicle fuels and are not in the scope of, and thus not described by, this document.

Note 2 to entry: In the business, the term “upgraded biogas” is also used instead of the term "biomethane”.

3.13
biomethane potential of biomass

potential of biomethane (3.12) production expressed in normal cubic metres per tonne dry matter of

biomass (3.9)
3.14
biomethane storage
buffer, gas holder, tank, vessel, cylinder or similar to store biomethane (3.12)

Note 1 to entry: In case of liquefied biomethane, this often concerns vacuum insulated tanks.

© ISO 2018 – All rights reserved 3
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SIST EN ISO 20675:2022
ISO 20675:2018(E)
3.15
bio-syngas

type of biogas (3.2), comprising principally carbon monoxide and hydrogen, obtained from gasification

(3.25) of biomass (3.9)
Note 1 to entry: Bio-syngas also contains traces of methane and carbon dioxide.
3.16
combined heat and power installation
CHP

gas engine, pilot spark ignition engine, gas turbine or fuel cell using gas to generate electrical power

and useful heat at the same time
Note 1 to entry: This is also called co-generation.
3.17
compressed biomethane
CBM

biomethane (3.12) used as a fuel for vehicles or for other purposes, typically compressed up to

20 000 kPa in the gaseous state
3.18
compressed natural gas
CNG

natural gas (3.39) used as a fuel for vehicles or other purposes, typically compressed up to 20 000 kPa

in the gaseous state

[SOURCE: ISO 14532:2014, 2.1.1.11, modified — the definition has been revised and Note 1 to entry has

been deleted.]
3.19
digestate

remaining effluent from the anaerobic digestion process including solid fraction and liquid fraction

3.20
digester
anaerobic digestion installation including reactors, tanks and related equipment
3.21
dry matter
remaining part of biomass (3.9) or digestate (3.19) after the removal of water
3.22
emergency flare

biogas flare (3.4) which is meant to combust biogas (3.2) during exceptional situations when the biogas

is not utilized

Note 1 to entry: Emergency flares can be of the type enclosed flare (3.23), enclosed high efficiency flare (3.24) or

open flare (3.43).
3.23
enclosed flare

biogas flare (3.4) which consists of an enclosed combustion chamber, where the flame is invisible from

the outside

Note 1 to entry: An enclosed flare is burning more efficiently with a relatively higher temperature than an open

flare (3.43), and the burning temperature can be monitored.
4 © ISO 2018 – All rights reserved
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SIST EN ISO 20675:2022
ISO 20675:2018(E)
3.24
enclosed high efficiency flare

biogas flare (3.4) which consists of an enclosed combustion chamber, where the flame is invisible from

the outside and the biogas is combusted at a monitored and automatically controlled temperature of

1 000 °C to 1 200 °C with a retention time of at least 0,3 s
3.25
gasification

process that converts biogenic or fossil-based materials into carbon monoxide and hydrogen

Note 1 to entry: This is achieved by exposing the material at high temperatures (>700 °C), without combustion,

with a controlled amount of oxygen and/or steam.

Note 2 to entry: Normally, the gasification is followed by conversion into methane and carbon dioxide

(methanation).

Note 3 to entry: The resulting gas mixture of carbon monoxide and hydrogen is called syngas (3.58). When the

feedstock of gasification is biomass (3.9), the resulting gas mixture is called bio-syngas (3.15).

3.26
gas infrastructure

pipeline systems including pipework and their associated stations or plants for the transmission (3.59)

and distribution of gas
3.27
gas pipeline

system of pipework for transportation of gas with all associated equipment and stations up to the point

of delivery

Note 1 to entry: This pipework is mainly below ground but includes also above-ground parts.

3.28
hydraulic retention time

theoretical average period of time a soluble compound remains in the digester (3.20)

Note 1 to entry: The hydraulic retention time (HRT) is calculated as net digester volume (m )/daily feedstock

input (m /day).
3.29
hydrocarbon dew temperature

temperature at a specified pressure at which hydrocarbon vapour condensation initiates

3.30
injectable biomethane

upgraded biogas (3.2) having natural gas (3.39) quality suitable to feed into the public grid and which

fulfils the legal requirements for feeding into the public grid
3.31
installation owner
legal entity, a company or natural person owning the biogas installation (3.5)
3.32
liquefied biogas
biogas (3.2) which has been liquefied
EXAMPLE Liquefied biomethane.
3.33
liquefied biomethane
LBM

biomethane (3.12) which has been liquefied, after processing, for storage or transportation purposes

© ISO 2018 – All rights reserved 5
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SIST EN ISO 20675:2022
ISO 20675:2018(E)
3.34
liquefied natural gas
LNG

natural gas (3.39) that has been liquefied after processing for storage or transportation purposes

Note 1 to entry: Liquid natural gas is revaporized and introduced into pipelines for transmission (3.59) and

distribution as natural gas.
3.35
lower heating value

amount of heat that would be released by the complete combustion with oxygen of a specified quantity

of gas, in such a way that the pressure, p, at which the reaction takes place remains constant, and all the

products of combustion are returned to the same specified temperature, T, as that of the reactants; all

of these products being in the gaseous state

[SOURCE: ISO 14532:2014, 2.6.4.2, modified — “inferior calorific value” has been replaced.]

3.36
methane content
mol percentage of methane in biogas (3.2) or biomethane (3.12)
3.37
methane number
rating indicating the knocking characteristics of a fuel gas

Note 1 to entry: It is comparable to the octane number for petrol. One expression of the methane number is the

volume percentage of methane in a methane-hydrogen mixture that in a test engine under standard conditions

has the same tendency to knock as the fuel gas to be examined.
[SOURCE: ISO 14532:2014, 2.6.6.1]
3.38
mixer
agitator within a digester (3.20) homogenizing the biomass (3.9) in the digester
3.39
natural gas

complex gaseous mixture of hydrocarbons, primarily methane, but generally includes ethane, propane

and higher hydrocarbons, and some non-combustible gases such as nitrogen and carbon dioxide

Note 1 to entry: Natural gas can also contain components or containments such as sulfur compounds and/or

other chemical species.
[SOURCE: ISO 14532:2014, 2.1.1.1]
3.40
natural gas network

network which is either a transmission (3.59) network or a local distribution system

Note 1 to entry: Network and grid have the same meaning.
3.41
normal cubic metres of gas

volume of one cubic metre for real dry gas at ISO Standard Reference conditions of 15 °C and 101 325 kPa

Note 1 to entry: In the industry, 0 °C and 101 325 kPa are also often used; however, in this document, the ISO

Standard Reference conditions are used.
6 © ISO 2018 – All rights reserved
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SIST EN ISO 20675:2022
ISO 20675:2018(E)
3.42
odorization

addition of odorants, normally intensively smelling organic sulphur compounds, to natural gas (3.39) to

allow the recognition of gas leaks by smell at very low concentration (before a build up to a dangerous

gas in air concentration can occur)

Note 1 to entry: Natural gas is normally odourless. It is necessary to add an odorant to the gas fed into the

distribution system for safety reasons. It permits the detection of the gas by smell at very low concentrations.

[SOURCE: ISO 14532:2014, 2.8.2]
3.43
open flare
biogas flare (3.4) from which the burning flame is visible from the outside
Note 1 to entry: This is also called external combustion flame burner.

Note 2 to entry: The flame burner combustion is not optimal; the combustion temperature is relatively low.

3.44
organic dry matter

part of biomass (3.9) or digestate (3.19) which consists of dry matter containing carbon and originating

from living materials

Note 1 to entry: Instead of organic dry matter, the term “total volatile solids” is also used.

3.45
organic loading rate digester

amount of volatile organic dry matter (3.44) entering the anaerobic digester (3.20) over time, measured

in kilograms per cubic metre digester volume per day

Note 1 to entry: The organic load gives an indication on biological degradation of the substrates (3.56). It provides

information on nutrient supply levels of the microorganisms involved, overload or undersupply of the system as

well as resulting technical and process control measures to be taken. The organic load describes the efficiency of

the anaerobic digester.
3.46
pipeline network

system of interconnected pipelines, both national and international, that serve to transmit and

distribute natural gas (3.39)

[SOURCE: ISO 14532:2014, 2.1.2.1, modified — “grid” has been replaced by “network”.]

3.47
power to gas
gas generated from electrical power from biomass (3.9) origin
3.48
raw biogas

biogas (3.2) directly from the digester (3.20) which is not conditioned, so it is not yet dried and cleaned

3.49
recovered gas

gases such as hydrogen, carbon dioxide, carbon monoxide and/or complex gaseous mixtures of

hydrocarbons, primarily methane, but generally includes ethane, propane and higher hydrocarbons,

and some non-combustible gases such as nitrogen and carbon dioxide which are recovered as a by-

product or residual product of gases from, for example, industrial or thermochemical processes not

being biogas (3.2) and not produced from biomass (3.9)

Note 1 to entry: Recovered gas can also contain components or containments such as sulfur compounds and/or

other chemical species.
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ISO 20675:2018(E)
Note 2 to entry: Usually, these gases have a fossil origin.
3.50
relative density

ratio of the mass of a gas contained within an arbitrary volume to the mass of dry air of standard

composition that would be contained in the same volume at the same reference conditions

3.51
renewable non-biogenic gas

gas such as hydrogen, carbon dioxide, carbon monoxide and/or complex gaseous mixtures of

hydrocarbons, primarily methane, but generally includes ethane, propane and higher hydrocarbons,

and some non-combustible gases such as nitro
...

SLOVENSKI STANDARD
oSIST prEN ISO 20675:2021
01-september-2021

Bioplin - Proizvodnja, priprava, nadgradnja in uporaba bioplina - Izrazi, definicije in

shema razvrščanja (ISO 20675:2018)

Biogas - Biogas production, conditioning, upgrading and utilization - Terms, definitions

and classification scheme (ISO 20675:2018)

Biogaz - Production, traitement, épuration et utilisation du biogaz - Termes, définitions et

classification (ISO 20675:2018)
Ta slovenski standard je istoveten z: prEN ISO 20675
ICS:
27.190 Biološki viri in drugi Biological sources and
alternativni viri energije alternative sources of energy
75.160.40 Biogoriva Biofuels
oSIST prEN ISO 20675:2021 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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oSIST prEN ISO 20675:2021
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oSIST prEN ISO 20675:2021
INTERNATIONAL ISO
STANDARD 20675
First edition
2018-02
Biogas — Biogas production,
conditioning, upgrading and
utilization — Terms, definitions and
classification scheme
Biogaz — Production, traitement, épuration et utilisation du biogaz
— Termes, définitions et classification
Reference number
ISO 20675:2018(E)
ISO 2018
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oSIST prEN ISO 20675:2021
ISO 20675:2018(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2018

All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may

be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting

on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address

below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva, Switzerland
Tel. +41 22 749 01 11
Fax +41 22 749 09 47
copyright@iso.org
www.iso.org
Published in Switzerland
ii © ISO 2018 – All rights reserved
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oSIST prEN ISO 20675:2021
ISO 20675:2018(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................iv

Introduction ..................................................................................................................................................................................................................................v

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms and definitions ..................................................................................................................................................................................... 2

4 Abbreviated terms .............................................................................................................................................................................................. 9

5 Classifications .......................................................................................................................................................................................................10

Annex A (informative) Explanation to the scope ..................................................................................................................................11

Annex B (informative) Biogas characteristics, processes and classifications ........................................................15

Bibliography .............................................................................................................................................................................................................................20

© ISO 2018 – All rights reserved iii
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oSIST prEN ISO 20675:2021
ISO 20675:2018(E)
Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national standards

bodies (ISO member bodies). The work of preparing International Standards is normally carried out

through ISO technical committees. Each member body interested in a subject for which a technical

committee has been established has the right to be represented on that committee. International

organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.

ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of

electrotechnical standardization.

The procedures used to develop this document and those intended for its further maintenance are

described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the

different types of ISO documents should be noted. This document was drafted in accordance with the

editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of

any patent rights identified during the development of the document will be in the Introduction and/or

on the ISO list of patent declarations received (see www .iso .org/ patents).

Any trade name used in this document is information given for the convenience of users and does not

constitute an endorsement.

For an explanation on the voluntary nature of standards, the meaning of ISO specific terms and

expressions related to conformity assessment, as well as information about ISO's adherence to the

World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see the following

URL: www .iso .org/ iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 255, Biogas.
iv © ISO 2018 – All rights reserved
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Introduction

The technical committee on biogas (ISO/TC 255) was established in 2011 in order to

— provide liberalization and facilitation for international trade of biogas installations,

— contribute to international cooperation on technical regulations, standards and assessment

procedures,

— curb discriminatory technical requirements as the main form of trade protectionism, and

— reduce and eliminate the technical barriers for international trade of biogas installations.

This document about terms, definitions and classifications is applicable for biogas production by

anaerobic digestion, gasification from biomass and power to gas from biomass sources, biogas

conditioning, biogas upgrading and biogas utilization.

The availability of a set of agreed terms and definitions for biogas installations, as well as a classification

scheme for the whole biogas chain, is necessary in order to

— moderate the communication between the different biogas parties through meaningful discussions,

— facilitate development of regional and national regulations and incentive programs to promote

biogas production and application,

— contribute to the reinforcement of biogas installations’ safety and business competitiveness with

recognized terms and definitions that clarify the actors’ expectations related to procurement,

contracts and services as well as reporting on biogas related action plans and road maps, and

— contribute to the use of standards by facilitating their development and furthering the users’

understanding and application of standards.

ISO/TC 255 intends to promote international technology exchange and to accelerate international

application of biogas (products) and equipment by developing and maintaining globally harmonized

standards.
© ISO 2018 – All rights reserved v
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oSIST prEN ISO 20675:2021
INTERNATIONAL STANDARD ISO 20675:2018(E)
Biogas — Biogas production, conditioning, upgrading and
utilization — Terms, definitions and classification scheme
1 Scope

This document defines terms and describes classifications related to biogas production by anaerobic

digestion, gasification from biomass and power to gas from biomass sources, biogas conditioning,

biogas upgrading and biogas utilization from a safety, environmental, performance and functionality

perspective, during the design, manufacturing, installation, construction, testing, commissioning,

acceptance, operation, regular inspection and maintenance phases.

Biogas installations are, among others, applied at industrial plants like food and beverage industries,

waste water treatment plants, waste plants, landfill sites, small scale plants next to agricultural

companies and small scale household installations.
The following topics are excluded from this document:

— boilers, burners, furnaces and lightening, in case these are not specifically applied for locally

produced biogas;
— gas-fuelled engines for vehicles and ships;
— the public gas grid;
— specifications to determine biomethane quality;
— transportation of compressed or liquefied biogas;
— transportation of biomass or digestate;
— assessment and determination whether biomass is sourced sustainably or not.
This document describes the following for information purposes as well:

— the parameters to determine the size (e.g. small, medium-sized, or large scale);

— the parameters to determine the type of installation (e.g. domestic, industrial);

— the parameters to describe the type of technique;

— terms and processes in order to develop health, safety and environmental protection guidelines for

biogas installations.
NOTE For an explanation of the Scope, see Annex A.
2 Normative references
There are no normative references in this document.
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3 Terms and definitions
For the purpose of this document, the following terms and definitions apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
anaerobic digestion

biological conversion of biodegradable materials by micro-organisms in the absence of oxygen creating

two main products: biogas (3.2) and digestate (3.19)

Note 1 to entry: An example of anaerobic digestion is the biological conversion of the biodegradable parts of

biomass (3.9) sources, but also fossil biodegradable sources.
Note 2 to entry: Wet and dry anaerobic digestion systems are applied.
3.2
biogas

gas produced by anaerobic digestion of organic matter, gasification (3.25) of biomass (3.9) or power to

gas from biomass sources and without further upgrading or purification

Note 1 to entry: Biogas comprises mainly methane and carbon dioxide and/or hydrogen and/or carbon monoxide

and/or heavier hydrocarbons with two till six carbon atoms.
Note 2 to entry: Bio-syngas (3.15) is also a type of biogas.
3.3
biogas boiler
boiler which uses biogas (3.2) as fuel
3.4
biogas flare
installation to burn biogas (3.2), whether superfluous or not

Note 1 to entry: A flare is applied for biogas generated in biogas installations (3.5) or extracted from landfill sites,

among others, to avoid methane and/or hazardous compounds to be emitted into the atmosphere. A biogas flare

can be applied as safety, environmental and/or process device.

Note 2 to entry: A typical flare consists of, among others, an ignition system, flame and temperature detection

system, windproof body and combustion chamber, biogas piping, valves, condensate drainage, electrical control

cabinet, installation fixtures, burner head, heat insulation and pilot or ignition burner.

Note 3 to entry: A flare can be classified in three main categories: open flare (3.43), enclosed flare (3.23) and

enclosed high efficiency flare (3.24).
3.5
biogas installation

installation including its pipelines, pipes and accessories for anaerobic digestion of biomass (3.9),

gasification (3.25) of biomass and waste, upgrading of biogas (3.2), liquefaction of biogas, storage of biogas

(in raw, gas or liquid form), storage of CO , storage of auxiliaries, storage of biomass and digestate (3.19)

Note 1 to entry: Upgrading of biogas includes cooling, compressing, heating, separation, reaction in order to

purify or upgrade the biogas to a higher methane percentage.
2 © ISO 2018 – All rights reserved
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3.6
biogas pipeline

system of pipework for transportation of biogas (3.2) or biomethane (3.12) with all associated equipment

and stations up to the point of delivery and outside the biogas installation (3.5)

Note 1 to entry: This pipework is mainly below ground, but includes also above-ground parts.

3.7
biogas storage
buffer, gas holder, tank, vessel, bag or similar to store biogas (3.2)
Note 1 to entry: The biogas storage can be part of the fermenter.
3.8
biogenic content
organic material from biomass (3.9)
3.9
biomass

material of biological origin excluding material embedded in geological formations and/or transformed

to fossilized material

Note 1 to entry: Biomass is organic material that is plant-based or animal-based, including, but not limited to

dedicated energy crops, agricultural crops and trees, food, feed and fibre crop residues, aquatic plants, alga,

forestry and wood residues, organic agricultural, animal and processing by-products, agricultural, municipal

and industrial organic waste and residues whether or not in landfills, sludge, waste water, and other non-fossil

organic matter.
3.10
biomass pipeline
digestate pipeline

system of pipework for transportation of liquid biomass (3.9) or digestate (3.19) with all associated

equipment and up to the point of delivery
3.11
biomass pretreatment

treatment of biomass (3.9) with chemical, physical, thermal and biological methods in order to increase

methane production when the biomass is digested or gasified
3.12
biomethane

methane-rich gas with the properties similar to natural gas derived from biogas (3.2) produced by

anaerobic digestion or gasification (3.25) or from power to gas by upgrading

Note 1 to entry: Requirements for chemical and physical properties of biomethane, such as heat content, flame

characteristics, dew points, traces of chemical compounds, are part of standards for injection of biomethane in

public grids and standards for vehicle fuels and are not in the scope of, and thus not described by, this document.

Note 2 to entry: In the business, the term “upgraded biogas” is also used instead of the term "biomethane”.

3.13
biomethane potential of biomass

potential of biomethane (3.12) production expressed in normal cubic metres per tonne dry matter of

biomass (3.9)
3.14
biomethane storage
buffer, gas holder, tank, vessel, cylinder or similar to store biomethane (3.12)

Note 1 to entry: In case of liquefied biomethane, this often concerns vacuum insulated tanks.

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3.15
bio-syngas

type of biogas (3.2), comprising principally carbon monoxide and hydrogen, obtained from gasification

(3.25) of biomass (3.9)
Note 1 to entry: Bio-syngas also contains traces of methane and carbon dioxide.
3.16
combined heat and power installation
CHP

gas engine, pilot spark ignition engine, gas turbine or fuel cell using gas to generate electrical power

and useful heat at the same time
Note 1 to entry: This is also called co-generation.
3.17
compressed biomethane
CBM

biomethane (3.12) used as a fuel for vehicles or for other purposes, typically compressed up to

20 000 kPa in the gaseous state
3.18
compressed natural gas
CNG

natural gas (3.39) used as a fuel for vehicles or other purposes, typically compressed up to 20 000 kPa

in the gaseous state

[SOURCE: ISO 14532:2014, 2.1.1.11, modified — the definition has been revised and Note 1 to entry has

been deleted.]
3.19
digestate

remaining effluent from the anaerobic digestion process including solid fraction and liquid fraction

3.20
digester
anaerobic digestion installation including reactors, tanks and related equipment
3.21
dry matter
remaining part of biomass (3.9) or digestate (3.19) after the removal of water
3.22
emergency flare

biogas flare (3.4) which is meant to combust biogas (3.2) during exceptional situations when the biogas

is not utilized

Note 1 to entry: Emergency flares can be of the type enclosed flare (3.23), enclosed high efficiency flare (3.24) or

open flare (3.43).
3.23
enclosed flare

biogas flare (3.4) which consists of an enclosed combustion chamber, where the flame is invisible from

the outside

Note 1 to entry: An enclosed flare is burning more efficiently with a relatively higher temperature than an open

flare (3.43), and the burning temperature can be monitored.
4 © ISO 2018 – All rights reserved
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3.24
enclosed high efficiency flare

biogas flare (3.4) which consists of an enclosed combustion chamber, where the flame is invisible from

the outside and the biogas is combusted at a monitored and automatically controlled temperature of

1 000 °C to 1 200 °C with a retention time of at least 0,3 s
3.25
gasification

process that converts biogenic or fossil-based materials into carbon monoxide and hydrogen

Note 1 to entry: This is achieved by exposing the material at high temperatures (>700 °C), without combustion,

with a controlled amount of oxygen and/or steam.

Note 2 to entry: Normally, the gasification is followed by conversion into methane and carbon dioxide

(methanation).

Note 3 to entry: The resulting gas mixture of carbon monoxide and hydrogen is called syngas (3.58). When the

feedstock of gasification is biomass (3.9), the resulting gas mixture is called bio-syngas (3.15).

3.26
gas infrastructure

pipeline systems including pipework and their associated stations or plants for the transmission (3.59)

and distribution of gas
3.27
gas pipeline

system of pipework for transportation of gas with all associated equipment and stations up to the point

of delivery

Note 1 to entry: This pipework is mainly below ground but includes also above-ground parts.

3.28
hydraulic retention time

theoretical average period of time a soluble compound remains in the digester (3.20)

Note 1 to entry: The hydraulic retention time (HRT) is calculated as net digester volume (m )/daily feedstock

input (m /day).
3.29
hydrocarbon dew temperature

temperature at a specified pressure at which hydrocarbon vapour condensation initiates

3.30
injectable biomethane

upgraded biogas (3.2) having natural gas (3.39) quality suitable to feed into the public grid and which

fulfils the legal requirements for feeding into the public grid
3.31
installation owner
legal entity, a company or natural person owning the biogas installation (3.5)
3.32
liquefied biogas
biogas (3.2) which has been liquefied
EXAMPLE Liquefied biomethane.
3.33
liquefied biomethane
LBM

biomethane (3.12) which has been liquefied, after processing, for storage or transportation purposes

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3.34
liquefied natural gas
LNG

natural gas (3.39) that has been liquefied after processing for storage or transportation purposes

Note 1 to entry: Liquid natural gas is revaporized and introduced into pipelines for transmission (3.59) and

distribution as natural gas.
3.35
lower heating value

amount of heat that would be released by the complete combustion with oxygen of a specified quantity

of gas, in such a way that the pressure, p, at which the reaction takes place remains constant, and all the

products of combustion are returned to the same specified temperature, T, as that of the reactants; all

of these products being in the gaseous state

[SOURCE: ISO 14532:2014, 2.6.4.2, modified — “inferior calorific value” has been replaced.]

3.36
methane content
mol percentage of methane in biogas (3.2) or biomethane (3.12)
3.37
methane number
rating indicating the knocking characteristics of a fuel gas

Note 1 to entry: It is comparable to the octane number for petrol. One expression of the methane number is the

volume percentage of methane in a methane-hydrogen mixture that in a test engine under standard conditions

has the same tendency to knock as the fuel gas to be examined.
[SOURCE: ISO 14532:2014, 2.6.6.1]
3.38
mixer
agitator within a digester (3.20) homogenizing the biomass (3.9) in the digester
3.39
natural gas

complex gaseous mixture of hydrocarbons, primarily methane, but generally includes ethane, propane

and higher hydrocarbons, and some non-combustible gases such as nitrogen and carbon dioxide

Note 1 to entry: Natural gas can also contain components or containments such as sulfur compounds and/or

other chemical species.
[SOURCE: ISO 14532:2014, 2.1.1.1]
3.40
natural gas network

network which is either a transmission (3.59) network or a local distribution system

Note 1 to entry: Network and grid have the same meaning.
3.41
normal cubic metres of gas

volume of one cubic metre for real dry gas at ISO Standard Reference conditions of 15 °C and 101 325 kPa

Note 1 to entry: In the industry, 0 °C and 101 325 kPa are also often used; however, in this document, the ISO

Standard Reference conditions are used.
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3.42
odorization

addition of odorants, normally intensively smelling organic sulphur compounds, to natural gas (3.39) to

allow the recognition of gas leaks by smell at very low concentration (before a build up to a dangerous

gas in air concentration can occur)

Note 1 to entry: Natural gas is normally odourless. It is necessary to add an odorant to the gas fed into the

distribution system for safety reasons. It permits the detection of the gas by smell at very low concentrations.

[SOURCE: ISO 14532:2014, 2.8.2]
3.43
open flare
biogas flare (3.4) from which the burning flame is visible from the outside
Note 1 to entry: This is also called external combustion flame burner.

Note 2 to entry: The flame burner combustion is not optimal; the combustion temperature is relatively low.

3.44
organic dry matter

part of biomass (3.9) or digestate (3.19) which consists of dry matter containing carbon and originating

from living materials

Note 1 to entry: Instead of organic dry matter, the term “total volatile solids” is also used.

3.45
organic loading rate digester

amount of volatile organic dry matter (3.44) entering the anaerobic digester (3.20) over time, measured

in kilograms per cubic metre digester volume per day

Note 1 to entry: The organic load gives an indication on biological degradation of the substrates (3.56). It provides

information on nutrient supply levels of the microorganisms involved, overload or undersupply of the system as

well as resulting technical and process control measures to be taken. The organic load describes the efficiency of

the anaerobic digester.
3.46
pipeline network

system of interconnected pipelines, both national and international, that serve to transmit and

distribute natural gas (3.39)

[SOURCE: ISO 14532:2014, 2.1.2.1, modified — “grid” has been replaced by “network”.]

3.47
power to gas
gas generated from electrical power from biomass (3.9) origin
3.48
raw biogas

biogas (3.2) directly from the digester (3.20) which is not conditioned, so it is not yet dried and cleaned

3.49
recovered gas

gases such as hydrogen, carbon dioxide, carbon monoxide and/or complex gaseous mixtures of

hydrocarbons, primarily methane, but generally includes ethane, propane and higher hydrocarbons,

and some non-combustible gases such as nitrogen and carbon dioxide which are recovered as a by-

product or residual product of gases from, for example, industrial or thermochemical processes not

being biogas (3.2) and not produced from biomass (3.9)

Note 1 to entry: Recovered gas can also contain components or containments such as sulfur compounds and/or

other chemical species.
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Note 2 to entry: Usually, these gases have a fossil origin.
3.50
relative density

ratio of the mass of a gas contained within an arbitrary volume to the mass of dry air of standard

composition that would be contained in the same volume at the same reference conditions

3.51
renewable non-biogenic gas

gas such as hydrogen, carbon dioxide, carbon monoxide and/or complex gaseous mixtures of

hydrocarbons, primarily methane, but generally includes ethane, propane and higher hydrocarbons,

and some non-combustible gases such as nitrogen and carbon dioxide which are produced from

renewable sources not being biogas (3.2) and not produced from biomass (3.9)

Note 1 to entry: Examples are gases produced via power to gas (3.47) processes from renewable power from

solar, wind, hydropower or geothermal sources, but not from biomass sources.
3.52
service provider

legal entity or a company operating on request of the biogas installation owner (3.31) and/or maintaining

the biogas installation (3.5)
3.53
solid retention time

period of time expressed in days the biomass (3.9) is in the digester (3.20) for anaerobic digestion

Note 1 to entry: The solid retention time (SRT) is calculated as the net capacity for biomass content in the

digester (kg)/daily feedstock input (kg/day).
3.54
specific biogas production

standard state volumetric biogas (3.2) production expressed in normal cubic metres per liquid volume

in cubic metres of the digester per day
3.55
specific biogas yield

standard state volumetric biogas production expressed in normal cubic metres per kilogram organic

dry matter (3.44) of the feedstock
3.56
substrate

part of the biomass (3.9) which is biodegradable and converted by microorganisms and/or enzymes as

catalyst into biogas (3.2) and/or degradable by gasification (3.25)
3.57
supplier of the biogas installation

legal entity or a company which designs, manufactures or constructs and delivers the biogas installation

(3.5) to the biogas installation owner (3.31)
3.58
syngas

gas, comprising principally of carbon monoxide and hydrogen, obtained from gasification (3.25) of

fossil fuels
3.59
transmission

activity intended to convey gas from one place to another through pipelines in order to supply gas to

distribution systems or to industrial consumers
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3.60
treated biogas

biogas (3.2) which is dried until a water dew point of at least 10 °C and conditioned by cleaning from

contaminants like hydrogen sulphide and siloxanes, but from which the CO and N percentages have

2 2
not been decreased yet
3.61
treated digestate

digestate (3.19) after partly removing the nutrients such as phosphates, nitrogen and/or water

Note 1 to entry: Treatment can be done by drying, pelletizing, and separating water and nutrients.

3.62
volatile fatty acid
fatty organic acid containing less than six carbon atoms

Note 1 to entry: These are intermediate products of the biogas (3.2) production process.

3.63
waste water treatment gas

biogas (3.2) produced by anaerobic waste water treatment installation or waste water treatment sludge

digestion
Note 1 to entry: Waste water treatment gas is often mentioned as sewage gas.
3.64
water dew point
temperature at a specified pressure at which water vapour condensation initiates

Note 1 to entry: For any pressure lower than the specified pressure, there is no condensation of water vapours at

this water dew point temperature.
[SOURCE: ISO 14532:2014, 2.6.5.1.1]
3.65
Wobbe index

calorific value on a volumetric basis at specified reference conditions, divided by the square root of the

relative density at the same specified metering reference conditions

Note 1 to entry: The Wobbe index is specified as superior (denoted by the subscript “S”) or inferior (denoted by

the subscript “I”), depending on the calorific value.
[SOURCE: ISO 14532:2014, 2.6.4.3]
4 Abbreviated terms
CBM Compressed biomethane
CHP Combined heat and power plant
CNG Compressed natural gas
HRT Hydraulic retention time
LBM Liquefied bio methane
LNG Liquefied natural gas
SRT Solid retention time
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5 Classifications

Biogas installations can be classified in different types (e.g. domestic, farm, industrial) and different

sizes (e.g. domestic scale, small scale, medium scale and large scale). Also, parts of the installations can

be classified in different pressure classes. Classifications are descriptions and categorizations used for

information and better understanding and do not contain technical requirem
...

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