perspectives for a european standard on biomethane: a biogasmax

Perspectives for a european standard on biomethane: a Biogasmax proposal

Written by: Paul Huguen and Gildas Le Saux Lille Métropole Communauté urbaine (LMCU)

reviewed by: Michael Beil, Fraunhofer IWESFrançois Cagnon, Aude Greninger and Frédérique Bravin, GDF SUEZArthur Wellinger, Nova Energie

December 2010

www.biogasmax.eu

Keywords:Biomethane, European standard, grid injection,

biomethane quality

Abstract:This document reports on stakes and aims of a

European standard on biomethane for gridinjection or use as a fuel.

First steps in the establishment of such a standard are described: implementation of common regulation between countries

and agreement on natural gas quality.This document focuses on relevant parameters

for the setting of a European standard andparameters that have to be studied.

CO-FINANCED BY THE EUROPEAN COMMISSIONProject supported by the European Commission Under RTD contract : 019795

coordinated by:

BIOGASMAX - Integra ted Pro jec t

No 019795 Perspectives for a European standard on biomethane

Proposal for a European technical specification on biomethane of 27 2010-11-05

Table of Contents Summary: in the perspective of the biomethane market expansion, a need for a flexible standard adapted to the local nature of biomethane; some actions are also needed to simplify methodologies ............................................................................................................................... 4

1. Context and method of the report .......................................................................................... 5

2. Standards on gas in Europe: concepts, issues and objectives of a common specification on biomethane .................................................................................................................................... 5

Concepts and definitions.....................................................................................................................................................5

Various natural gases/various biogases.............................................................................................................................5

The challenges to overcome ...............................................................................................................................................6

Stakes and aims of a European standard on Biomethane..............................................................................................6

3. The different types of substrates used for biogas production in Europe .............................. 7

4. Biomethane utilization in Europe: grid injection, direct use as a fuel .................................. 9

The current standards on grid injection and/or use as a fuel........................................................................................9

The Netherlands, standard injection of biomethane from landfills .......................................................................... 10

Strict rules in France in place with some flexibilities: .................................................................................................. 10

Switzerland allows two qualities of biomethane for grid injection ............................................................................ 11

Sweden, biomethane directly used as a fuel; some experience on grid injection..................................................... 11

5. First steps in the introduction of a European standard on biomethane: current regulation and recommendations .................................................................................................................. 11

EASEE-gas: harmonization of units and of quality parameters of natural gas ....................................................... 12

MARCOGAZ: “Technical Association of the European Natural Gas Industry”.................................................. 13

KIWA: comparison of parameters defining quality of biomethane in Europe....................................................... 13

AFG (Association Française du Gaz): specification for grid injection of biomethane in distribution network ...... 13

European Committee for Standardization (CEN) ....................................................................................................... 13

Current work on standardization at the international level: ISO............................................................................... 13

6. Comments regarding comparison of European specifications ............................................14

Biogasmax recommendations regarding specifications applied in different countries........................................... 14

7. Parameters defining biomethane quality: proposals and perspectives ................................16

The current legal parameters of biomethane................................................................................................................. 16

For a common technical specification, some crucial parameters have to be defined............................................. 16

Assessing engine performance regarding the biomethane quality: the "Sonic Bievo Index"................................ 18

Biogasmax proposal - Important parameters to consider for a standard on biomethane ..................................... 18

Parameters with a need for further researches and assessment ................................................................................. 21

8. Recommendations for a EU standard for biomethane grid injection ................................. 22

Injection in high pressure natural gas grid of low methane content biomethane ................................................... 23

Injection of upgraded biomethane.................................................................................................................................. 23

Appendix 1. Technical specifications applied in European countries ....................................... 25




Tables and figures

Figure 1 : Origins and transport of natural gas in Europe ............................................................................... 6

Figure 2. Number of biomethane plants by sources in Europe in 2008 (plants having an upgrading unit for biomethane)....................................................................................................................................................... 8

Figure 3. Types of combinations of fermentable waste in 20082 (plants that have an upgrading step to biomethane) ............................................................................................................................................................. 9

Figure 4. Biomethane injection or valorization as a fuel in Europe in 20082 .............................................. 10

Table 1 – Common business practices : harmonization of units (since 2005) ............................................ 12

Table 2. Harmonized parameters of gas by EASEE-gas................................................................................ 12

Table 3. Water dew point – units and values.................................................................................................... 15

Table 4 - Summary table - Biogasmax recommendations for an harmonization of units ......................... 16

Table 5. Biogasmax proposal - Parameters defining biogas quality .............................................................. 17

Figure 5. Theoretical composition of an H and L gas..................................................................................... 19

Table 6 - Injection in high pressure natural gas grid of low methane content biomethane : a Biogasmax proposal for a European technical specification.............................................................................................. 23

Table 7 – Substitution for natural gas : a Biogasmax proposal for a European technical specification on biomethane ............................................................................................................................................................ 24




Summary:

in the perspective of the biomethane market expansion, a need for a

flexible standard adapted to the local nature of biomethane; some

actions are also needed to simplify methodologies

Anticipating the fossil gas depletion

In a near future when fossil sources are depleted, biomethane as a renewable energy, will ensure the continuity of supplying the natural gas network by a local and decentralized production. At a European scale, implementation of a common standard on biomethane aims to promote its uses and to develop such an energy source. Nowadays, various regulations and specifications for gas and biomethane are applied in each country.

A way of sustaining new biomethane projects

Since the European gas market was opened in 2007, harmonization of standards regarding biomethane uses between countries is a crucial issue. Such a standard along with defining a common technical specification will ensure that the quality of biomethane is stable throughout Europe. Stable quality will lead to positive conditions, i.e. similar tunings for upgrading units and analyses equipment, as well as a distinct falling-off of investments and operation costs by an economy of scale. Authorization procedures for biomethane injection into the grid will be significantly simplified as soon as quality requirements will be fulfilled, which will help local stakeholders to implement such projects.

The common standard should be flexible and take into account current European experiences

Nevertheless, for an EU standard not to add a further barrier but to be a driving force for biomethane expansion, conditions for success will have to be met. An EU standard will have to ensure flexible technical specifications. Consequently, legal frameworks currently applied in the present injector countries will have to be considered as a basis beyond which a common technical specification will not be defined.

Therefore, enforcement of European specifications for natural gas, such as those from EASEE-gas association, is not conceivable to biomethane.

Biogasmax proposal for a European technical specification on biomethane : please refer to the chapter untitled “Recommendations”

The need for further researches

In order to simplify as much as possible analysis methodologies at the producer site, several studies have to be carried out:

� Possible correlation of removal of couple H2O/H2S. Because of their chemical properties and molecule size, hydrogen sulfide and water would be removed during drying phase of the process, notably by using activated carbon filters for precise desulfurization and TSA technology for drying.

� Way to lighten measurement practices: certification of upgrading units for the removal of particular components such as ammonia, chlorine, fluorine, siloxanes or mercury.

� Importance to carrying out further surveys and monitoring on biomethane use in order to examine impacts of minor biomethane pollutants on engines, grids…




1. Context and method of the report

At the occasion of the European Conference on Biomethane Fuel in Göteborg in September 2009, where the main findings of Biogasmax project were presented, the Consortium was asked by the European Commission (EC) to set up a proposal for a European technical specification on biomethane. This was specifically requested by both Anne Houtman, Chief of unit in the former Directorate General Transport and Energy (DG TREN) and Antonio Tricas, European officer responsible for Biogasmax project at the EC.

This task has consequently been coordinated by Lille Métropole Communauté Urbaine (LMCU, who is also the coordinator of this FP 6 project) represented by Paul Huguen.

Following partners and experts have contributed to this analysis and proposal: Arthur Wellinger (Nova Energie), Michael Beil (IWES), François Cagnon, Frédérique Bravin and Aude Greninger (GDF SUEZ), Pierre Hirtzberger, Gildas Le Saux, Paul Huguen (LMCU) and Christian Couturier (Solagro, as an external expert)

The purpose of this report has been to provide the EC (and especially the CEN) with knowledge and a cross analysis of upgraded biogas used in the Biogasmax project and to draw recommendations for the establishment of a European Standard on biomethane.

This report seeks to answer the following questions:

� What are the reasons to set up a European standard on biomethane?

� What has already been done towards such a EU standard?

� What are the technical parameters specifying the biomethanes quality? What have been the issues raised by the cross-analysis of European experiences carried out here by Biogasmax?

� What are the cconditions for success of a common standard on biomethane, in perspective of a market expansion for biomethane?

2. Standards on gas in Europe: concepts, issues and objectives of a

common specification on biomethane

Concepts and definitions

A standard (also called « technical specification ») defines a quality of gas (biomethane in our case). Thresholds on parameters and compounds of gas... (e.g. heating value, water content, hydrogen sulphide content...) are expressed in units.

On the one hand, equipments (upgrading unit, compressors...) must be tuned to reach the specifications (in agreement with the valorisation/injection needs). On the other hand, the vehicles could be optimized to have the best operating conditions with the gas quality defined within the specifications (in most cases they will be adapted to the natural gas quality).

Various natural gases/various biogases1

Natural gas: Europe is crossed by numerous gas pipelines that ensure transportation of natural gas from principal extraction areas - notably Russia, North Sea or Algeria - to the European consumers. This supply may be completed with LNG carrier transportation.

Locally, gas quality depends on its origin, i.e. the mixture of different gases and on the respective gas specification, like the two natural gases H (High calorific value) and L (Low calorific value) in France.

1 Biogasmax WP 4/Task 5.2,”Guidelines on technical, economical, legal and institutional aspects of grid injection and possible strategies for different local conditions”,2010.




Figure 1 : Origins and transport of natural gas in Europe

Biogas: Like the composition of natural gas depends on its origins, methane content of biogas varies from 50 to 70%, depending on the feedstock composition. Upgrading and cleaning phases enable biogas to match the local or national regulation and specification for natural gas when biomethane feeds in grid. The different production processes of biogas also affect the content of minor polluting compounds.

So, biomethane has a common feature with natural gas: the main component is methane, that’s why it can be used as a substitute to natural gas. But although quality of biomethane is met, the minor components may differ from one biomethane to another or from biomethane to natural gas. This will depend on a series of factors (substrates used, upgrading process involved…). Often the major difference between upgraded biogas and the local natural is it’s heating value. Whereas biomethane bases fully on the methane content, natural gas may contain substantial amounts of short chain aliphatic hydrocarbons with high heating values.

The challenges to overcome

An harmonization of standards on biomethane has to deal with the following issues:

- Today, each biomethane plant needs to be adapted to a technical specification (called “SPEC”) applying locally/regionally/nationally,

- And, throughout Europe, several SPECs are applied according the countries or regions involved.

This diversity of standards inhibits biogas expansion throughout Europe

The question is then: how to meet:

- on the one hand, the need for biomethane expansion in Europe as part of opening gas market?

- on the other hand, the requirements for trading, and of course for safety of equipments and people?

Stakes and aims of a European standard on Biomethane

Making the opening of the gas market feasible at a European level.

Once European Directives have opened the gas market in 2007, cross-border gas trade became easier for smaller companies. Gas suppliers and transporters have been quickly confronted to the gas quality disparities between standards of European countries. In order to support international trades, associations such as EASEE-gas, set up Common Business Practices (CBP) defining gas quality that enables a gas to be sold in the European market.




Nowadays, some border treatments on natural gas (desulfurization, odorization) take place in order to match the local regulations on gas transportation or distribution.

Anticipating the fossil gas depletion.

The expansion of the biomethane production on a local scale is in line with the scope of the development of decentralized electricity and other energy sources. Development of biomethane, as a renewable energy, aims to help European countries to anticipate the fossil sources depletion and especially Gas Peak. Hence biogas is pointed out to be a local source of energy whereas natural gas stocks are geographically irregular and have a limited lifetime.

The need for flexibility, taking into account current European experiences.

Establishing a standard on biomethane aims at:

• overcoming the various regional specifications

• setting a common basis for grid injection into the natural gas networks and for the use of biomethane as a vehicle fuel locally produced.

National standards currently in application would be harmonized with a European regulation, in an extent that has to be defined (regulation on a series of parameters or wide guidelines…).

However, countries that have already implemented SPECs such as Germany, Switzerland, France or Sweden will not have to be prejudiced by a more stringent European standard than their current rules in application. European experiences have therefore to be taken into account to draw up the European regulation on biomethane.

It is important to keep in mind that more than twenty years of injecting biomethane into the grid (intermesh of studies, experimentations and stable practices) are recorded in precursor countries. This experience in biomethane grid injection enables to prove the reliability of the technology applying the current specification, since almost no bad feedback has been reported.

A common framework for a sustainable development of biomethane.

European standard on biomethane will simplify procedure of validation of biomethane injection into the grid. Quality will be driven by common parameters.

Such quality definition would be a way to allow a common tuning for biogas upgrading units and for analysis equipment. Investment costs will thus be cut down, notably with effects of numbers of equal installations.

Biomethane will thus be used at different scales, locally when injected into distribution networks and possibly region/nationwide when injected in transportation networks. Its quality, ensured by the parameters defined in the European standard, will guarantee its easy and safe use for natural gas based applications.

It may be here noticed that once biomethane expanded, some section of distribution networks might be strictly supplied with biomethane, especially in summer time when gas consumption is the lowest (e.g. as the network in Lille metropolitan area when only a few buses will be operating in the area due to scholar holidays).

3. The different types of substrates used for biogas production in Europe

Switzerland and The Netherlands were the main forerunners in biogas recovery. At the present time, Germany, Sweden and Switzerland are equipped with numerous operating installations, each country having its own specificities:

- The Netherlands is the only country that injects biomethane from landfill biogas into the natural gas grid. In France, it is allowed but it has not been implemented so far. This practice is strictly forbidden in Switzerland, Austria and Germany8. Indeed, the latter countries point out the fact that landfills are suspected to emit halocarbon derivatives that could react when combusted and form furanes and dioxins, highly carcinogenic compounds.




- France and Austria have reached an experimental step of biomethane production with only few plants. Veolia in France has experienced biomethane production from landfill gas, for use in vehicle.

- Sweden produces significant amount of biomethane from sewage sludge (waste water treatment plant) alone or in combination with biowaste, energy crops and manure.

Dutch biomethane is mainly extracted from landfill gas. The other European projects involved in the study (Austria, Germany, France, Sweden and Switzerland), produce their biomethane from substrates such as biowaste, sewage sludge, energy crops and manure, in variable proportions.

Figure 2. Number of biomethane plants by sources in Europe in 20082 (plants having an upgrading unit for biomethane)

Since the study the numbers of plants have increased substantially, especially in Germany. In Europe around 150 plants are upgrading biogas to biomethane.

Despite a large development in Germany, energy crops are a sensitive issue and raise questions regarding sustainability. The latter substrates are specially cultivated with the aim of producing biogas. The conflict regarding land uses change represents the major issues. Indeed, intensive cropping may lead to environmental problems, however this is not unique to energy crops. With reasonable best practice including crop rotation, the problem can be marginalized.

It should be noted that practices regarding energy crops may differ from site to site: some have developed an intensive culture but other ones have implemented an integrated approach such as the Växstkraft project in Västerås (Stockholm region, Sweden). In the latter case, energy crops are an additional substrate (less than 20% of the whole feedstock): clover is cultivated and is, meantime, a way of preparing and improving soils for food cultures.

2 IEA Bioenergy, “Biogas upgrading technologies – developments and innovation”, October 2009




Figure 3. Types of combinations of fermentable waste in 20082 (plants that have an upgrading step to biomethane)

Total mixing (Figure 2) stands for combinations of changing fermentable wastes, in various quantities: sewage sludge/biowaste, manure/biowaste, manure/energy crop and a few of multi sources waste, called “other”. France has not yet biomethane production plants that combine agricultural waste with other sources of biodegradable waste.

By mixing waste like sewage sludge with co-substrates, biogas yield is enhanced. This practice is commonly used in Sweden and in Switzerland to recover as much as possible biodegradable waste.

4. Biomethane utilization in Europe: grid injection, direct use as a fuel

The current standards on grid injection and/or use as a fuel

- France: National guidance (décret) n°2004-555 dated 15th of June 2004

- Germany: Standards DVGW G 260 (2008) on gas composition, G 262 (2004) on injection of renewable

gases in public grids, G 280-1 and G 280-2 on odorization

- Switzerland: Directive SVGW G13 (2009)

- Sweden: Standard SS 155438

- Austria: Directive OVGW G31 (2001) and G33 (2006)

- The Netherlands: proposition from Dte (regulator), updated by Dutch gas grid operators in 2009

The cross analysis of the different technical specifications shows that threshold values of the major parameters (carbon dioxide, hydrogen sulfide, water, heating value) are quite in the same range. Some specificity exist in some countries on some minor compounds, depending mainly on the substrates used for biomethane production and the characteristics of natural gas in grids.

The Netherlands and France have quite stringent thresholds on minor parameters (Mercury, Chloride, and

Fluorine) as biomethane from landfills is allowed for grid injection.

In Sweden, heating value of biomethane has to be enhanced to match the Swedish natural gas standard for fuel used. Propane is thus added to biomethane. This practice also takes place in Germany but is forbidden in Switzerland, whereas other European countries do not refer to it.




The SS 15 54 38 established in 1999 is only applicable to direct utilization as vehicle fuel. It has been used ad hoc as a basis for the national specification of gas quality for injection into the natural gas grid. This has been highlighted in the Marcogaz report in 2006, some data actually not being part of the standard (e.g. H2 limit). There are no official guidelines in place; all other aspects such as Wobbe index (propane addition to reach the high energy content of the Danish gas utilized in Sweden) is dealt within the contracts.

Figure 4. Biomethane injection or valorization as a fuel in Europe in 20082

The Netherlands, standard injection of biomethane from landfills

Dutch biomethane has to fulfill stringent quality requirements as defined in the Dutch standard. It was established with regard to landfill biomethane, which is known to contain a number of polluting trace compounds: hydrocarbons and BTX (Benzene, Toluene, Xylene), acids (cyanhydric acid HCN and chlorhydric acid HCl), chloride, fluorine or siloxanes.

Steal pipes are very sensitive to acids: it is important to remove these acidic compounds in order to preserve natural gas network integrity.

However, the real need to regulate (and consequently monitor) these specific parameters has still to be proven, as experiences have shown that the current technologies seem able to remove these compounds during the cleaning and upgrading process (source: C. Couturier, Solagro).

When used as a fuel, biomethane has to be free of siloxanes. Oxidation of these compounds occurs in engines during burning and creating silicium oxide. The compound is highly abrasive and covers up the whole mechanical parts of CNG engine, in particular pistons.

Strict rules in France in place with some flexibilities:

The technical specifications for grid injection were established in 2006, but the first biomethane grid injection in practice is planned early 2011 only in Lille3. A pilot project was built in 1999 on the Montech landfill, but injection had not been allowed because the central administration gave no authorization due to a supposed presence of phosgene which could lead to a risk regarding health (since, it has been demonstrated that biomethane does not contain phosgene). French standard on biomethane has been built partly on the basis of this experimentation (notably regarding mercury content).

3 Prescriptions techniques du distributeur GrDF, mars 2009, Prescriptions prises en application du décret n°2004-555 du 15 juin 2004 relatives aux prescriptions techniques applicables aux canalisations et raccordements des installations de transport, de distribution, de stockage de gaz.




In addition, several other parameters are regulated in France (chloride or fluorine) unlike other countries implementing already biomethane grid injection.

More generally, SPEC is the same for all type of biomethane. Even if the specifications are the same, the type and the frequency of the controls required by the grid operator may be less stringent for biomethane from biowaste than for biomethane from landfills. For instance, the same SPEC is applied to biomethane produced from biowaste (whose quality is high when organic waste is sort out in a separated manner by inhabitants) as well as from landfill. The latter presenting some higher risks regarding contents of Mercury, Chloride or Fluorine.

Nevertheless, France allows, according the local projects, some flexibility on parameters. Oxygen content may be increased from 0,01% to 3%mol. when the biogas producer proves that water and H2S content are low, in accordance with local gas network quality (if the pipe is in iron, oxygen and water content has to be to a lower value than for polyethylene pipe) For instance, oxygen and carbon dioxide contents can be increased to higher values that still match specification of heating value and Wobbe index: 3% O2 and 11.3% CO2 for L gas in North of France, as shown in Figure 4.

In Lille, L gas is supplied, hence 3% mol. Oxygen content and 11% CO2 content will be allowed by the grid owner.

Moreover, “Injection-Mixing” can be considered in case of injection into a transportation grid with a sufficient flow of natural gas (control of the gas quality after mixing biomethane into natural gas).

Switzerland allows two qualities of biomethane for grid injection

Grid injection of upgraded and cleaned biogas, notably of H2S, and with high methane content (CH4 > 96% vol.) is presently a common and well-established practice. Moreover, Swiss standards allow grid injection of cleaned biomethane but with a low methane content (CH4 > 50% vol.) however only with limited injection (5% volume of biogas in natural gas network, calculated on summer volumes) into a transport network. The five percent limit of low methane biogas warranties a high dilution in natural gas, with the mixture still matching the required heating value. The quality parameters of low and high methane content biomethanes have to match the same SPEC, expect for biomethane content.

In a limited number of upgrading plants (in two at present) the gas is directly used as vehicle fuel.

Sweden, biomethane directly used as a fuel; some experience on grid injection

Göteborg has implemented grid injection whereas other Swedish sites have developed direct use in vehicles. This particular development is enabled by a developed CNG vehicle market, a non-restrictive standard and about 15 years of experience on biomethane production, upgrading and utilization. Moreover, natural gas network is not widespread in Sweden. A natural gas network only exists along the South-West coast, where biomethane grid injection occurs.

Sweden is supplied with Danish natural gas that is characterized by a high methane content. Therefore, propane needs to be added to match the Wobbe index of the natural gas.

The current regulation does not take into account any of the non-common parameters such as heavy metals, halogens, acids and siloxanes.

5. First steps in the introduction of a European standard on

biomethane: current regulation and recommendations

Numerous projects and working groups have drawn up recommendations, regulation or specification with more or less ambition and implementation.

Associations or working groups made the first move when drawing a comparison of several European standards (KIWA, MARCOGAZ). The French environmental and health security agency (AFSSET, now ANSES) validate grid injection of biomethane in France4, notably concerning microbiological risks. At a European scale, two

4 Biomethane produced from any waste except sewage sludge and industrial waste (food-process industry waste are accepted)




working groups (CEN TC 19 and CEN-TC 234-WG 9) are planned to be mandated by the European Commission to work out a common standard for grid injection and vehicle use respectively.

EASEE-gas: harmonization of units and of quality parameters of natural gas

EASEE-gas association (European Association for the Streamlining of Energy Exchange – gas) is a group of European gas suppliers and producers. The association has been focused on the development of a European market of natural gas, mainly with the setting-up of Common Business Practices (CBP). Two main CBP were developed and are today agreed by most of the European gas companies. One deals with harmonization of gas units in order to make gas trades easier. The second significant CBP defines crucial parameters and their concentration in natural gas.

The quality of natural gas is thus regulated at a European level and, as soon as a gas matches these specifications, it can be traded easily.

Nevertheless, these CBP are hardly enforceable with biomethane, as explained in section 7.

The main lines of the two CBP are described in the table and the figure below:

Table 1 – Common business practices : harmonization of units (since 2005)

harmonization of units5 (date of implementation: 2005.10.01)

Pressure bar

Energy kWh (at a reference temperature of combustion of 25 oC)

Volume: Nm3 (0 °C / 1.01325 bar)

Heating value kWh/Nm3 (at a reference temperature of combustion of 25 oC)

Characteristic values of natural gas and composition6

Values are only implementable to cross-border transportation of H gas.

Table 2. Harmonized parameters of gas by EASEE-gas

Parameter unit min max implementation date

Wobbe index kWh/Nm3 13.60 15.81 2010.10.01

Density - 0.555 0.700 2010.10.01

Total sulfur mgS/m3 - 30 2006.10.01

H2S + COS mgS/m3 - 5 2006.10.01

RSH mgS/m3 - 6 2006.10.01

O2 % mol. - 0.001a 2010.10.01

CO2 % mol. - 2.5 2006.10.01

Water dew point °C at 70 bar - - 8 2006.10.01

Hydrocarbon dew point °C at 1-70 bar - - 2 2006.10.01

a Limit is <0.001 mol%, daily average. However, cross border point daily average levels up to 0.01 mol% will be accepted if these are the result of the prudent operation of UGS’s (Underground Gas Storage) , existing in 2006, which use oxygen for desulphurization purposes. (Based on the full CBP Wobbe range).

5 EASEE-gas CBP 2003-001-01 harmonization of units 6 EASEE-gas CBP 2005-001-02 harmonization of natural gas quality




MARCOGAZ: “Technical Association of the European Natural Gas Industry”

MARCOGAZ gathers actors of gas industry of twenty European countries and aims to promote natural gas and the development of its utilization. In this way, working groups take part in the setting-up of recommendations and standards on gas in Europe.

The report7 published in 2006 is based on the recommendation of harmonization of natural gas quality made by EASEE-gas. The association first drew up an exhaustive table of standards on biomethane currently in application in Europe. This work points out the differences between standards.

The report makes only an inventory of regulations without making any proposition regarding a common regulation for biomethane.

KIWA: comparison of parameters defining quality of biomethane in Europe

The report published by KIWA Gas Technology in 20078 is relatively detailed in information concerning biomethane and gives a full table of all parameters taken into consideration in several European countries, but without pointing out the need of a common standard.

This document is presented as an inventory of the different uses of biomethane in each country. It describes the specificities of standards on biomethane currently in application.

AFG (Association Française du Gaz): specification for grid injection of biomethane in

distribution network9

The French Gas Association gathers the French actors of natural gas (distribution grid operators, transportation grid operators, suppliers) and associations focused on gas.

AFG has compiled both GrDF technical specifications and Agence française de sécurité sanitaire de l’environnement et du travail (AFSSET)’s conclusions10. Implementation of such parameters is specific to French regulations and is only allowed in the distribution network of natural gas, the technical specification for transport grid injection being in late-2010 is still under progress.

Only biomethane that fulfilled quality parameters defined in the distribution grid operator’s technical prescriptions and in accordance with the assessment of waste type according the French National Health Agency (AFSSET) is allowed to be injected into the distribution grid (except biogas from sewage sludge).

Several research thesis and studies11 dealing with the measurement of microorganism populations and diversity in natural gas, biogas and ambient air, have shown a lower microbiologic risk of biogas compared to air and natural gas. So far, the French National Health Agency AFSSET has not published any opinion on biogas produced with sewage sludge.

European Committee for Standardization (CEN)

The European Commission plans to mandate this organization with the aim to set up a standard on biomethane.

Two working groups have been set up and met in a regular basis: CEN TC 19 (fuel) and CEN TC 234 WG 9 (grid injection). Some actors (among them GDF SUEZ) would prefer a single group to be created (rather than two distinct approaches) in order to prevent the setting-up of two distinct specifications on biomethane.

Current work on standardization at the international level: ISO

7 MARCOGAZ, WG-Biogas-06-18 “Injection of Gases from Non-Conventional Sources into Gas Networks”, 01/12/06 8 Kiwa gas Technology, GT-070127 “Quality Aspects of Biogas”, 21/09/2007 9 AFG, Cahier des charges pour l'injection de BIOGAZ dans le réseau de distribution, B 562-1, March 2010 10 AFSSET, Evaluation des risques sanitaires liés à l’injection du biogaz dans le réseau de gaz naturel, October 2008 11 Thesis of Marina Moletta, “Caractérisation de la diversité microbienne aéroportée des biogaz » INRA, 2005




A group of stakeholders on natural gas vehicles has started since March 2009 a work on common fuelling station

standards/ regulation, in perspective of a strategy for a biomethane standard.

Conclusion. Remaining work to be done is still considerable. However significant stages have been overcome, notably with adoption of CBP (EASEE-gas) and common specification for gas between gas suppliers and transporters: harmonization of units that aims to develop trades.

6. Comments regarding comparison of European specifications

Biogasmax recommendations regarding specifications applied in different countries

A number of European countries developed their own specifications concerning gas concentrations, volumes, energies, etc. that may rise some problems when SPECs from different countries are to be compared. Indeed, data is not always expressed in the international system of unit (SI). Below, the main parameters and their units are presented as well as Biogasmax’ comments and recommendations (please also refer to the summary table at the end of this chapter).

Unit of content/concentration

A common concentration unit for gases is volume fraction (%vol.). However, more units are sometimes used: ppm or mole faction (%mol.) for instance in the French specifications.

In addition, the standard ISO 697612 relative to natural gas calculations, presents the formula below that make possible conversion of volume fraction to molar one:

Where xj is mole fraction

yj is volume fraction

Zj is compression factor

t2 and p2 are respectively the temperature and the pressure of measurement

Compression factor depending on temperature12, volume and molar fractions are thus two ways to express gas content against the other components.

However, at normal condition (0°C and 1.01325 bar), if volumes are considered in Nm3, %vol. and %mol. Are equal.

Comparison between European specifications is therefore difficult because of the unit disparity. Moreover, some publications do not specify any units for gas content, often leading to confusion and errors.

Recommendation 1: Make a common unit proposal for gases content

Unit of volume

In some publications volumes are not expressed in normal cubic meters (Nm3), which are standard conditions of

pressure and temperature (1.01325 bar/0°C).

It can be assumed that it is an omission, but definition of such a condition on volume measurement is rightfully

relevant because gas volume is varying significantly with temperature.

Recommendation 2: Only one unit for volume should be used: Nm3

12 ISO 6976:1995, Natural gas - Calculation of calorific values, density, relative density and Wobbe index from composition




Wobbe index

Wobbe index and Heating value are both important characteristics of natural gas and biomethane. However, units in the publications consulted are either given in kWh/Nm3 or MJ/Nm3. Both are correct and relevant, but when converting (1 kWh = 3.6 MJ), discrepancy occurs in reports.

In addition, in some countries (such as Sweden) lower Wobbe index is used whereas upper Wobbe index is used in others.

Recommendation 3: Proposal for units: both Wobbe Index and Heating value should be expressed in MJ/Nm3 and

kWh/Nm3.Use a proper conversion factor (1 kWh = 3.6 MJ) in calculation.

Water dew point.

As for water content in gas, several units and parameters are varying between European specifications: pressure and temperature of measurement are significantly different as shown in the table below.

Table 3. Water dew point – units and values

France Germany Switzerland Sweden Austria Netherland

Dew point

< - 5°C b

Ground

Temperature at

related grid

pressure

ф < 60% c

Dew point

- 9°C at 200bar

or 32 mg/m3

Dew point

- 8°C at 40 bar 32 mg/m3

b Below -5°C at Maximum Service Pressure on the system below the Connection

c Relative humidity: defined as the ratio of the partial pressure of water vapor in the gas to the saturated

vapor pressure of water at a prescribed temperature

The water dew point is a crucial parameter to define the gas quality. It ensures that at high pressure and in tanks of CNG vehicles no water condensation occurs in order to prevent corrosion of metallic parts.

Recommendation 4: Correlation of Gergwater enables conversion from mass content into temperature of dew point. A common unit

has to be defined.

Relative density

Some countries do not define a range of relative density (d) for biogas. This data is nevertheless important because it is part of the Wobbe index (Iw) calculation as well as of the heating value (Hv):

Recommendation 5: A range of relative densities has to be defined. The density of air (1.293 kg/m3) as well as standard condition of

pressure and temperature (101325 Pa, 0°C) have to be mentioned, since they are part into relative density calculation.

Hydrocarbon dew point

Austria, France and Germany require to gas producers the measurement of temperature of hydrocarbon dew point. This parameter enables characterization of hydrocarbons, except methane. As measurement of water dew point, the unit used for the temperature and pressure of such a parameter is different according countries.




Table 4 - Summary table - Biogasmax recommendations for an harmonization of units

Field Current situation Recommendations from Biogasmax

Unit of content/concentration

Several units used according

countries :%vol.; %mol. Make a common unit proposal for gases

content

Unit of volume Only one unit for volume should be used:

Nm3

Wobbe index Units vary between publications from kWh/Nm3 to MJ/Nm3

Proposal for units: units of Wobbe index and

Heating value should both kWh/Nm3 and

MJ/Nm3

Use a proper conversion factor (1 kWh = 3.6 MJ) in calculation

Water dew point Several units and parameters are varying between European specifications

Correlation of Gergwater enables conversion from mass content into temperature of dew point. A common unit has to be defined

Relative density Absence of this important parameter

A range of relative density has to be defined. d = 0.555 – 0.700 seems to be mostly used

7. Parameters defining biomethane quality: proposals and perspectives

The current legal parameters of biomethane

In Appendix 1 is presented a table of current regulated parameters for biogas injection into the natural gas grid or fuel using.

Parameters that are directly influencing the biogas quality are: Wobbe index, water dew point, CO2, O2, N2, content of some minor components such as H2S, total sulfur.

Some countries that regulate biomethane with stringent standards, notably France and The Netherlands, take into consideration several other minor components that are mostly in traces amount: ammonia, carbon monoxide, mercury, chlorine, fluorine, siloxanes or BTX (Benzene, Toluene, and Xylene).

Because of traces amount, quantification of such parameters is complicated and needs specific equipment that represent a high-cost investment.

If these parameters (e.g. for siloxanes) are suggested to be added to a European standard, the frequency of

measurements, the applicable methods and especially the sampling has to be defined.

In the Netherlands, injection of biomethane extracted from landfill is allowed into the natural gas grid. Therefore, measurement of some parameters such as siloxanes is relevant because of the waste sources. But historically minor pollutants are regulated in biomethane and the most particular one is mercury, which is only taken into account in France.

These first observations point significantly out the importance of the implementation of a common regulation at a European scale, notably in the purpose to inject biomethane into the natural gas grid.

For a common technical specification, some crucial parameters have to be defined

In the perspective of a common technical specification, some crucial parameters have to be considered; the relevance of other needs to be demonstrated

A comparison of current European standards (Appendix 1) points out two types of parameters that define biomethane quality:




- The important parameters are virtually all present in the national standards on biomethane but have sometimes very distinct values. Oxygen content is one of the most crucial parameter (in the UK but also in France).

- The “Uncertain” parameters. Since the measurement of such compounds in traces amount is complex and costly, reliability of the quantification of such parameters has to be proven. These parameters may be in “traces” levels, which mainly depend on the feedstock used for biogas production.

The table 5 below attempts to classify on one hand the “crucial” and, on the other hand, the “uncertain” parameters that are actually compounds of biomethane, but do not suggest any content and concentration since these values have to be based on several sources: experiences of grid injection, studies that aim to define effects of such compounds on natural gas network and burning systems (engine, boiler…) and reachable range of value with current upgrading technologies.

Table 5. Biogasmax proposal - Parameters defining biogas quality

Important

parameter

Uncertain

parameter

Methane x

Heating value x

Wobbe index x

CO2 x

CO x

O2 x

H2 x

H2S x

Mercaptans (RSH) x

THT x

Total sulfur x

NH3 x

Relative density x

Water dew point x

Siloxanes (as Si) ?

Hydrocarbon dew point ?

Mercury (Hg) ?

F ?

Cl ?

dust ?

HCl ?

HCN ?

BTX (Benzene, Toluene, Xylene) ?

PAH ?

The EASEE-gas proposal for harmonization of gas quality established in 2006 applies for some compounds. This harmonization has been set up to meet gas operators’ interests. This regulation is only enforceable to natural gas for cross-border trades; it can not be applied to biomethane, due to the specificities of the latter.




Assessing engine performance regarding the biomethane quality: the "Sonic Bievo

Index"

In the Biogasmax report “Influence of H2S Poisoned Biomethane on Catalyst Performance”13 (www.biogasmax.eu), Biogasmax has proposed a new index, the so-called “Sonic Bievo Index”.

How biomethane can reach the light-duty and heavy-duty NGVs’ fuel specifications?

In Biogasmax, the research organization TNO has assessed the impact of key gas parameters, usability in NGVs and the impact on catalyst performance. Following conclusions can be drawn:

Biomethane quality can be used in almost all NGV’s without influence on the NGV’s performance, fuel economy and emissions:

- “Regional regulated” biomethane qualities (with e.g. CH4 content of approx. 95% or higher) can be used in all LD-NGV’s as well as all HD-NGV’s specified for the “HL” or “H” fuel range.

- Even exceptional low biomethane quality (e.g. with a CO2 content of approx. 10%) can be used in all LD-NGV’s, but also in all HD-NGV’s if designed for the L or HL fuel quality range

- Even the highest possible biomethane (upgraded biogas) gas quality will never exceed both light-duty as well as heavy-duty NGV fuel specifications. The exception is upgraded biogas with additional propane. In that case (which is a typical Swedish particularity), some LD-NGV’s may run into problems. Exact calculation of a specific index, the so-called “Sonic Bievo Index”, is required to check this combination.

Biogasmax proposal - Important parameters to consider for a standard on biomethane

Methane (CH4): Methane-content in biomethane has to reach a minimum threshold of 96%, as shown by Eric Zinn14, for grid injection (except for L gas).

In addition, injection into transportation network of a poor methane-content biogas could be allowed, according specific conditions as in Switzerland. When injected in a transport grid, dilution of a low methane-content biogas into natural gas has to be considered. It is also possible in Germany, a so called injection of “Zusatzgas” and in France, called

“Injection-Mixing”.

Heating value and Wobbe index

Values of both parameters are varying widely between countries and within country where the two types of gas L and H apply. Upgrading technologies and purification of biogas enable methane content of biomethane, and thus heating value, to match local specifications.

In a L gas network, decreasing heating value is easily reachable by reducing biogas upgrading and increasing carbon dioxide content, which is the major by-product of anaerobic digestion. Other minor compounds content is nevertheless not increased because upgrading technologies are really efficient in pollutant concentration reduction.

Conversely, increasing heating value, a common practice in Sweden, is done by adding a higher heating potential gas, such as propane, to biomethane. Addition of such a fossil source product in biomethane could be given up by extending Wobbe index range. A wider interval would enable harmonization of upgrading units’ tunings and ensuring a good biomethane quality.

One important suggestion can be that a biomethane producer is responsible to reach a minimum CH4 content or alternatively reach a Wobbe Index or heating value range. The grid operator is responsible for the conditioning process to reach (if required for his gas grid)

13A.J. Bruijstens, M.v.d. Molen, W.P.H, Beuman, W.A.J. Bleuanus, TNO Automotive - Björn Hugosson, City of Stockholm Local Consortium - Pierre Hirtzberger, Lille Metropole Urban Community - All BIOGASMAX partners contributed to this report - January 2008 14 Guidelines on technical, economical, legal and institutional aspects of grid injection and possible strategies for different local conditions, Eric Zinn, October 2010




the exact Wobbe Index and exact heating value. This system is applied in Germany and regulated in the “Gasnetzzugangsverordnung” (Gas Network Access Ordinance).

Carbon dioxide (CO2)

As a product of digestion, it is the second major product composing biogas. Austria and France are the strictest countries as for this parameter. A maximum threshold of 6% in The Netherlands, Switzerland and Germany seems to be properly defined since it ensures Wobbe index value to be in agreement with national legislations.

However, threshold could be defined as the maximum carbon dioxide content of biomethane that makes sure the heating value to be reached. As an example, the chart below points out French CO2 threshold that can be calculated in order to match the French technical specification.

Figure 5. Theoretical composition of an H and L gas

*Nitrogen and hydrogen are not taken into account in this figure.

Source : GrDF, 2010

Carbon monoxide (CO)

A few feedbacks on this parameter. It is only regulated in France and in The Netherlands. CO is easily quantifiable even though content after biogas upgrading is mainly below detection threshold.

Relevance of measurement of this parameter has to be shown. It is more relevant for a thermo-chemical production of biomethane and not for biomethane from anaerobic digestion.

Oxygen content (O2)

German, Swedish and Swiss oxygen contents in biomethane should be used as references for establishment of a European regulation. The flexibilities allowed in French SPEC could also be a relevant tool (please refer to page 9).

O2 is a critical parameter only in UK. The required contents regarding O2 in this country significantly low in comparison with the other European countries. Due to the specificities of biomethane (cf. page 4), applying such a low content to the latter is not relevant.

Why to be strict for O2 content in natural gas and why allowing some flexibility on biomethane?

High oxygen content is feared mostly for possible corrosion effects of oxygen on steel composing pipes and particularly when gas is humid. Corrosion risks of pipes are then enhanced.

The really low oxygen content proposed by EASEE-gas association6 (100 ppm content) for natural gas come from the SPEC requested by the French operator of transport of gas. Because of a higher risk of humidity in underground storage systems situated on transportation grids, low content of O2 is necessary in order to preserve the integrity of storage systems, pipes and networks.

As biomethane does not need to be stored in such deep system, this threshold is not enforceable to biomethane when it is used locally.

As a local source of energy, biomethane is not transported as much as natural gas. Indeed, most of the biomethane is injected into distribution network only. Hence, a European




standard on biomethane would be flexible and would take into consideration state (age, type of material, corrosion risks) of the distribution network in which biomethane will be injected.

In addition, setting-up of a threshold should take into consideration the dilution that occurs when injecting biomethane into the grid (in a distribution grid dilution would hardly occur in summer). Thereby higher oxygen content could be allowed since dilution is important, this depending on the localization of the injection unit and the flow of the grid.

Furthermore, it should be noted that upgrading technologies are not able to reach such level of oxygen content. For these two reasons, threshold regarding O2 has to be risen for biomethane standard, as the European experiences (including France) have shown.

One suggestion for a European standard could be that there are two different concentrations

defined: One for distribution grid and one for transport grid. The real problem of oxygen

(besides in metallic tubes) is the underground storages that might be degraded with oxygen.

However there are not too many storages along the gas grids with biomethane. Hence the

recommendation should be with high oxygen contents (> 1%) and specifications for

storages and metallic grids.

Hydrogen (H2): H2 maximum content is high in all countries, except in Sweden. This parameter takes part in the heating value calculation (as well as the Wobbe Index calculation and the octane or methane number if used as fuel and in that case H2 is a very important parameter because it decreases the methane or octane number). Having a restricted range of heating value, Sweden ensures that hydrogen does not reach high content in order to control easily heating value by adding propane.

However, hydrogen represents only a negligible part in biomethane (from anaerobic digestion) composition and does not seem to raise problems.

Extension of interval of heating value is nevertheless wished in order to get rid off any compounds that would influence heating value of biomethane.

High Hydrogen content will ensure grid injection of biomethane from gasification.

Sulphurous compounds (H2S, RSH):

The concentration allowed by European countries regulation in application for hydrogen sulfide or mercaptans are similar. Moreover, contents are easily reachable with current desulfurization and upgrading technologies.

Studies carried out within the Biogasmax project15 point to the fact that below 30 ppm of H2S in biomethane, none or almost no effects are noticed on NGVs engines, as well as regarding efficiency of combustion or of post combustion treatment. Current European regulations, harmonization of natural gas quality and desulfurization technologies agree about a limit value of 30 mgS/Nm3 in natural gas.

Sulphurous compounds have been taken into account since a long time and are regulated so as to respond to demands of gas operators, gas producers and European regulations.

Water content (H2O):

It is an essential parameter in the definition of a gas quality. It ensures that, even at high pressure, no condensation of water can occur that prevent grid from any risk of corrosion.

Temperature of water dew point seems to be the most used unit in current standards of the European countries.

Couple of pressure and temperature of measurement of such a parameter has to be clearly

15 Biogasmax WP5/Task 5.2, “Report on influence of H2S poisoned biomethane on catalyst performance”, 2008




defined because disparities exist between countries.

Parameters with a need for further researches and assessment

The following parameters are regulated at a national scale essentially in the two strictest countries on biomethane quality: France and The Netherlands. For some parameters, it seems to be important to set a threshold; for other, it is arguable and it has to be studied further.

Mercury (Hg)

Only quantified in France, measurement of Hg can be really debated for several reasons: campaign of mercury quantification in biomethane shown contents in biomethane lower than in ambient air (monthly measurements in Lille). Sorted biowaste are always pretreated by shredding, metal removing and screening, which confer to biowaste a composition exempt from any sources of mercury. Moreover, most of upgrading units are equipped with activated carbon that fix and remove traces of mercury in biomethane (source: Michael Beil).

Up to now, no bad feedback of mercury has been noticed on installations and vehicle using biomethane as a fuel.

A study is currently carried out at the Gas Technology Institute in the USA that aims at determining the appropriate mercury content for biomethane injection into natural gas grid.

Siloxanes (R2SiO):

They are residual compounds from cosmetic formulation and from building material. Siloxanes are thus only found into biomethane extract from landfill or produced by anaerobic digestion of sewage sludge from Wastewater Treatment Plant (WWTP).

Biowaste, manure and rest of food are free from any sources of siloxanes and biomethane produced from these sources would not contain any traces of such compounds.

Siloxanes can damage, after combustion phase, engines and mechanical parts of CNG vehicle since they are oxidized in silica (SiO2) that has high abrasive properties.

No study has been carried out yet in order to define precisely a threshold of siloxanes in biomethane. The Netherlands and Austria defined a regulation on siloxanes as a limit of these compound expressed in mass of silicon per cubic meter.

Studies should be done on the assessment of a threshold value in biomethane that ensures integrity (when combined or not to natural gas) of gas networks, engines as well as boilers.

A certificate of waste type, especially for green and biowaste, could be considered and would avoid the measurement of siloxanes whether the source has been shown not to contain any traces of them. This practice already takes place in Germany.

A suggestion for the definition of a threshold for the sum parameter siloxane or better organic

silicon compounds can be the requirements of CHP manufacturers.

Temperature of hydrocarbon dew point:

In the manner of condensation of water in gas, traces amount of hydrocarbons could condensate at high pressure.

Measurement of such a parameter is a common practice for natural gas, which contains a combination of several hydrocarbons, of which methane is the principal. Therefore, this parameter is relevant for natural gas. Conversely, quantification of hydrocarbons in biogases shows extremely low content of such compounds, except for Sweden where propane is added to biomethane to enhance heating value, relevance has to be shown. However, propane is only added if grid injection is applied. If using biomethane directly as vehicle fuel it is disadvantageous to add propane because of possible condensation effects.

In Germany, approximately 40 plants add propane to the biomethane.




Halogen and derivatives content (Cl, F, RCl, RF):

These compounds are only measured in France and in The Netherlands. Corrosive properties of such compounds for grid or CNG vehicle tanks are pointed out and explain the fear from the latter countries. The measurements made in biogases (in Lille, for instance) and their combustion products show very low content of Halogen and derivatives matching current regulations in application. Measurement of such parameters is relevant for landfill gas that contain higher traces than other biogases.

Transportation installations or industrial combusting systems such as boiler can be affected by halogen compounds. Into the grid, chlorine and fluorine are potentially corrosive when they are under acid form. Metallic canalizations are thus highly sensitive to such corrosive compounds.

Acid forms of chlorine and fluorine could, after combustion of halogen derivatives, lead to corrosion effect describe previously in case of the formation of water.

Presence of chlorine could also be a precursor of dioxins when burnt in a boiler. However, no study set a limit of chlorine to prevent dioxins.

Only a few studies have been carried out for two reasons: natural gas is free from halogens, hence issues of corrosion of metallic part of transportation installations are not much known. In addition, corrosion problems of halogens occur in particular condition of gas humidity, which lead to the formation of acids that take effect on the long range on the grid.

Studies have to be done to assess capacities of transportation and transformation installations to tolerate corrosion and to determine on which range.

Aromatic compounds

Known as PAH (Polycyclic Aromatic Hydrocarbons) and BTX (Benzene, Toluene, Xylene), aromatic compounds are essentially present in landfill biogas. They are suspected, for some of them, to be carcinogenic but no limit content in the air or in gases has been defined.

Synergetic effects

Well known in chemistry, properties of a compound in a system are amplified, here negatively, when other compounds are added in the system.

In the case of natural gas, a compound, such as carbon dioxide, inert in a dry gas can be highly corrosive when combined with water or a too high humidity of gas. Several acids could thus be formed during the transportation or using phase: HCl, HF, H2SO4, H2CO3. Thereby, a humid gas with high oxygen content presents corrosive properties.

8. Recommendations for a EU standard for biomethane grid injection

The tables 6 and 7 below describe the recommendations made by the Biogasmax project and that should be taken into consideration for the establishment of a European standard for biomethane. The values and contents of required quality parameters take into account the European experience of countries in biomethane grid injection and use as a fuel.

Two types of injection exist, involving two types of biomethane. Biogasmax makes here a proposal for each of one: :

- Dilution of low methane content biogas (> 50 % vol.). This biogas is dewatered and cleaned from pollutants but is not upgraded. It is diluted by injection into high pressure natural gas grid. A limited volume of such a biogas that can be injected is defined by the grid operator (maximum of 5% vol. of biogas in natural gas network, calculated on summer volume)

- Substitution of natural gas with upgraded biogas (= biomethane). Unlimited volume of biomethane can be injected into both distribution and transport networks as a substitute of natural gas. The Wobbe Index of such a biomethane is adapted to local conditions of natural gas supply (H or L gas). Propane can be added to biomethane in order to reach the Wobbe index that is required locally.




Injection in high pressure natural gas grid of low methane content biomethane

No Wobbe Index can be defined for such a biogas, only a minimum methane content is considered. Injection of such a biogas is profitable to the producers when the cost of compression of such a biogas in order to be injected in a high pressure grid is lower than the cost of an upgrading unit. In addition, the biogas plant has also to be located closed to a transportation grid.

Table 6 - Injection in high pressure natural gas grid of low methane content biomethane : a Biogasmax proposal for a European technical specification

Parameter Unit Comments

Methane %vol. > 50 dewatered and cleaned but not upgraded biogas

Relative density dn - Not required

Other parameters Please refer to the SPEC for grid injection of upgraded biomethane

Biogasmax, 2010

Injection of upgraded biomethane

Some preliminary remarks about the European technical specification proposed here by Biogasmax

In the tables below, Biogasmax project proposes a series of values for a European technical specification on parameters defining biomethane quality. It should be noted that:

- This proposal has been built on the basis of

o the numerous experiences regarding biomethane grid injection throughout Europe.

o Especially, organic silicon compounds requirement is based on CHP manufacturers’ data. The frequency of measurement of such quality parameters will be discussed as part of the contract between biomethane producer and grid operator.

- These values need to be considered as tentative figures. They may consequently evolve according further experiences and oncoming lessons learnt from current practices.

- All kind of feedstocks (used as substrates for biogas production) are concerned by this proposal: biowaste, garden waste, manure, sewage sludge, energy crop, landfill, etc.

- The European SPEC that is proposed here seeks to ensure a flexibility to the local/regional/national grid operators:

o In comparison with SPECs applied in some countries,, additional parameters are proposed here. Grid operator will define case by case whether biomethane producer has to measure these parameters or not: This will depend on the feedstock used (for instance, the measurement of biomethane produced from source-separated collected biowaste involves less parameters than biomethane produced from landfills (as the latter deals with more minor pollutants). The kind of upgrading technology used has also to be taken into account.

o Such flexibility will consequently allow the biomethane producer to meet the grid operator’s requirements in an easier way.

- Biomethane producer has to warranty the feedstock origin to the grid operator.




Table 7 – Substitution for natural gas: a Biogasmax proposal for a European technical specification on biomethane

Common parameters (all types of biomethane)

Parameter Unit L-Gas H-Gas Comments

kWh/m³ 10.86 – 12.44 12.69 – 15.19 Wobbe Index (range) WS,n

MJ/m³ 39.1 – 44.8 45.7 – 54.7

Range of Gross Wobbe Index at 15°C and 1013.25 mbar as mentioned in

standard EN 437.

Propane addition is allowed to reach the required range

kWh/Nm³ 8.4 – 13.1 Range of current SPECs in Europe Heating value (range) HS,n MJ/Nm³ 30.2 – 47.2 Range of current SPECs in Europe

Relative density dn - 0.55 – 0.75 Range of current SPECs in Europe

CO2 Vol.-% ≤ 11 ≤ 6 Range of current SPECs in Europe

Hydrocarbons (without CH4):

condensation point °C

Soil temperature (related to grid pressure of connected

grid)

To be measured only when heating value is enhanced by adding hydrocarbons

(propane)

Water dew point °C Soil temperature Related to grid pressure of connected

grid

Dust - Technically free

O2 % ≤ 3 Range of current SPECs in Europe

Sulphur (total) mgS/Nm³ ≤ 30 Odorant included

THT mg/Nm3 15-40 Range of current SPECs in Europe

H2S mg/Nm³ ≤ 5 Range of current SPECs in Europe

H2 Vol.-% ≤ 10

Range of current SPECs in Europe : <5. Nevertheless, H2 threshold value has to be enhanced to allow biomethane from

gasification

NH3 mg/Nm³ ≤ 3 - 20 Range of current SPECs in Europe

Additional parameters (depending on specific substrates) (Based on current range applied in Europe)

Parameter Unit Considered feedstock

Organic silicon compounds

(calculated as Si) mg/Nm³ ≤ 10 landfill, sewage sludge

F mg/Nm³ ≤ 10 - 25 landfill, sewage sludge

Cl mg/Nm³ ≤ 1 - 50 landfill, sewage sludge

Hg µg/Nm³ ≤ 1 landfill



Biogasmax: proposal for a European standard on biomethane of 27 2010-08-18

Appendix 1. Technical specifications applied in European countries

France Germany (1) Switzerland Sweden Austria Netherlands

Unlimited Limited

Unit H gas L gas H gas L gas

Injection Injection

kWh/Nm3 13.64-15.7 12.01-13.06 12.8-15.7 10.5-13.0 13.3-15.7 - 13.3-15.7 -

Wobbe Index MJ/Nm3

48.24-56.52

(higher)

42.48-46.80

(higher) 46.1-56.5 (higher) 37.8-46.8 (higher) 47.9-56.5

- Type A (2):

44.7-46.4 (lower)

Type B (2):

43.9-47.3 (lower)

47.7-56.5

(higher)

43.46-44.41

(higher)

kWh/Nm3 10.7-12.8 9.5-10.5 8.4-13.1 10.6-13.1 - 10.7-12.8 8.8-10.8 Gross calorific

value MJ/Nm3 38.52-46.08

(higher)

34.2-37.8

(higher) 30.2-47.2 38.5-47.2

- - 38.5-46.0 31.6-38.7

Methane vol % - - > 96 > 50 > 97 (2) 96 -

CO2

< 2.5 mol %

(Flexibilities exist for specific

conditions

e.g. in Lille: <11%)

< 6 vol % < 6 vol % < 4 vol % (3) < 3 vol %

< 6 mol %

< 10-10.3 % for

regional grid

CO mol % < 2 - < 0.5 - - < 1

O2 vol %

< 100 ppmv

(flexibilities exist for specific

conditions

e.g. in Lille: <3%)

< 0.5 (<3 if dry gas) < 0.5 < 1 < 0.5 < 0.5

H2 vol % < 6 < 5 < 4 - < 4 < 12

< 5 H2S mg/Nm3

(H2S + COS) < 5 < 5 < 10 ppm (4) < 5 < 5

Mercaptans

(RSH) mg/Nm3 < 6 < 16 < 5 ppmv - < 6 < 10

Total sulphur mgS/Nm3 < 30 < 30 < 30 < 23 < 10 < 45




NH3 mg/Nm3 < 3 - < 20 < 20 - < 3

dew point < -5°C dew point <-9°C

200bar

dew point <-

8°C H2O

at MOP (5)

Dew point at ground temperature

(related to corresponding grid pressure)

ф < 60% (6)

or < -8 °C at MOP (< 32 mg/m3) at 40 bar

< 32 mg/m3

or < -10 °C at 8 bar

Hydrocarbon

dew point < -2°C (1-70 bar)

Condensation point at ground temperature (related to

corresponding grid pressure) - -

< 0°C at OP

(7) -

Relative density - 0.555-0.70 - 0.55-0.70 - - 0.55-0.65 -

THT mg/Nm3 15-40 The gas has to be odorized 15-25 - -

> 10 mg/Nm3

Average 18

mg/Nm3

Mercury (Hg) µg/Nm3 < 1 - - - - -

Siloxanes (as Si) - - - - < 10

mgSi/Nm3 < 5 ppmv

F mg/Nm3 < 10 - - - - < 25

Cl mg/Nm3 < 1 - - - - < 50

Dust mg/Nm3 - technically free - < 1 µm technically

free technically free

HCl ppmv - - - - none < 1

HCN ppmv - - - - none < 10

BTX (Benzene,

Toluene, Xylene) ppmv - - - - - < 500

Aromatic

hydrocarbons mol % - - - - - < 1

(1) For grid injection due to DVGW G 260 and G 262

(2) 97 % ± 1 (type A*) and ± 2 (type B*)

(3)The sum of CO2, O2 and N2 is max 4% (type A) or 5% (type B)

(4) 10ppm = 15.2 mg/Nm3

(5) MOP: Maximal Operating Pressure, downstream from injection point (ISO 18 453 « Natural gas – Correlation between water content and water dew point. » (Correlation of Gergwater).)

(6) ф: Relative humidity

(7) OP: Operating Temperature

* Type A: biogas as vehicle fuel – Engines without lambda control

Type B: biogas as vehicle fuel – Engines with lambda control

perspectives for a european standard on biomethane: a biogasmax

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