CO 2 emission factors for fuels in the Netherlands

Transcription

1 Nederlandse Organisatie voor toegepast-natuurwetenschappelijk onderzoek / Netherlands Organisation for Applied Scientific Research Laan van Westenenk 501 Postbus AH Apeldoorn The Netherlands TNO-report R 2002/174 CO 2 emission factors for fuels in the Netherlands T F info@mep.tno.nl Date April 2002 Authors Drs. A.K. van Harmelen Ing. W.W.R. Koch Order no Keywords Intended for CO 2 emission factor Carbon emission factor Fuel Novem Ministry of VROM Project group CO 2 monitoring All rights reserved. No part of this publication may be reproduced and/or published by print, photoprint, microfilm or any other means without the previous written consent of TNO. In case this report was drafted on instructions, the rights and obligations of contracting parties are subject to either the Standard Conditions for Research Instructions given to TNO, or the relevant agreement concluded between the contracting parties. Submitting the report for inspection to parties who have a direct interest is permitted TNO

2 TNO-MEP R 2002/174 2 of 42 Table of content 1. Introduction Approach Present emission factors and prioritisation Interpretation of emission factors Overview of present emission factors Sources and quality of present IPCC EFs Sources and quality of present national EFs Solid fossil fuels (primary and secondary) Liquid fossil fuels (primary and secondary) Gaseous fossil fuel Priority setting Analysis of new information on fuels Consistency of CO 2 calculations Measurements and factors Criteria for adoption of new CO 2 emission factors Primary solid fossil fuels Secondary fuels from solid fossil fuels Primary liquid fossil fuels Secondary fuels from liquid fossil fuels Primary Gaseous fossil fuels Other fuels Conclusions & recommendations References List of Abbreviations...41 Appendix A Appendix B The IPCC CO 2 methodology Oil data

3 TNO-MEP R 2002/174 3 of Introduction In 1999 a start has been made to improve the quality of existing emission inventories of greenhouse gases and to determine and minimise the uncertainties. The main reasons for improving the quality of the existing emission inventories are rooted in the following international developments: The adoption of new reporting guidelines and the Common Reporting Format under the Framework Convention on Climate Change; The Kyoto protocol: development of guidelines for the national system (art. 5), supplemental information (art. 7) and review (art. 8) 1 ; IPCC: development of Good practice guidance for emission inventories 2. The IPCC has put it in very concrete terms: when countries use local values of CO 2 emission factors instead of default IPCC emission factors, they should note the differences from the default values and provide to the IPCC documentation supporting the values used in the national inventory calculations. Moreover, the intensified national climate policy as described in the Implementation note on Climate Change policy Part 1 (in Dutch: Uitvoeringsnota Klimaatbeleid, deel 1 ) requires an improvement of the quality of the emission inventory of greenhouse gases. In the autumn of 1999 two national workshops were held in the Netherlands in order to determine the state of affairs concerning the monitoring of greenhouse gas emissions and sinks and to determine points of improvement. As a result of these workshops the Working group monitoring of greenhouse gas emissions (in Dutch: Werkgroep Emissiemonitoring Broeikasgassen - WEB ) was founded to coach and monitor the process to improve the monitoring of greenhouse gas emissions in the Netherlands. Representatives of relevant ministries and research institutes (Statistics Netherlands CBS, National Institute of Public Health and the Environment RIVM, Netherlands Organization for Applied Scientific Research TNO) are seated in this working group. The working group established a project group on CO 2 monitoring that is responsible for determining and improving the uncertainties in the process of CO 2 emission monitoring in the Netherlands. This project group initiated the present study on the determination and documentation of 1 2 As a result of the Kyoto Protocol each party shall have in place, no later than one year prior to the start of the first commitment period, a national system for the estimation of anthropogenic emissions by sources and removals by sinks of all greenhouse gases not controlled by the Montreal Protocol (article 5). Besides this, each party is obliged to incorporate the necessary supplementary information for the purposes of ensuring compliance with Article 3 of the Kyoto Protocol (article 7). Furthermore it is stated in the Kyoto Protocol that each Party shall be reviewed as part of the annual compilation and accounting of emissions inventories and assigned amounts (article 8). In the framework of the Intergovernmental Panel on Climate Change (IPCC) it is compulsory to include an uncertainty discussion in the inventory submission. To do so it is necessary to have insight in the quality of the a set of emission factors.

4 TNO-MEP R 2002/174 4 of 42 tiated the present study on the determination and documentation of CO 2 emission factors of fuels in the Netherlands. The set of CO 2 emission factors for fuels used in the Netherlands is presently only applied by parties in the Netherlands involved in the greenhouse gas emission inventory directly or indirectly under the umbrella of FCCC, viz. research institutes, governments and (smaller) companies that do not measure their emissions directly. Most large companies measure their emissions on the spot, present them in Environmental reports and provide their emission estimations to the national Pollutant Emission Register. These companies are not obliged to use standard emission factors. The objective of this study is to evaluate the documentation and validity of the present national set of CO 2 emission factors and to analyse the currently available information in the literature and at companies in order to make recommendations for the adoption, maintenance and further improvement of reliable, well-founded and documented CO 2 emission factors for fuels used in the Netherlands. If information on uncertainty of the data is available, these are presented. However, uncertainty is not an explicit aim in this study, but the main subject of a separate study on the uncertainty of greenhouse gases by IVM and ICIS that is currently being executed (report forthcoming). The results presented in this report have been reported and discussed with the project group CO 2 monitoring. The recommendations for further actions on the adoption, maintenance and further improvement of the set of emission factors are directed to the project group on CO 2 monitoring that is responsible for implementation of the recommendations.

5 TNO-MEP R 2002/174 5 of Approach Two research steps have been taken to evaluate the documentation and validity of the present national set of CO 2 emission factors in order to make recommendations for a reliable, well-founded and documented set of CO 2 emission factors for fuels used in the Netherlands: 1. Exploration and prioritisation; 2. Collection of new information and recommendations for improvement of national CO 2 emission factors. The objective of the first step was to analyse the foundation and documentation of the set of CO 2 emission factors presently in use in the Netherlands, to determine the available sources of information and to establish priorities for updating documentation and calculation of Dutch CO 2 emission factors. The results of step 1 are described in section 3. Present emission factors and prioritisation. The prioritisation takes place on the basis of: The reliability and validity of the emission factor; The quality and age of the documentation; The contribution of specific fuels to national CO 2 emissions; The difference with the default IPCC CO 2 emission factor. The contribution to national CO 2 emissions has been assessed by consulting the Dutch Pollutant Emission Register (PER), also called the Emission Inventory System (EIS), which contains the emissions to air, water, soil and waste both from all industrial and non-industrial sources. The emission inventory of 1998 has been analysed to indicate the importance of different fossil fuels in terms of their contribution to the national CO 2 emission. Together with a quality assessment of the national CO 2 emission factors presently in use and a comparison of default IPCC CO 2 emission factors, this resulted in a priority setting in terms of fuels that are important for more thorough investigation in step 2. Closer examination of the emission inventory generated additional information on the individual sources of the CO 2 emission and hence gave insight in the companies and institutes to be approached for more specific data in step 2. The second step analyses new, recent information and makes recommendations for the improvement of CO 2 emission factors for the Netherlands. The results of this step are described in section 4. Analysis of new information on fuels. Step 2 started with approaching the selected companies and institutes with a request for cooperation to collect the latest specific data. This resulted in specific information on the composition and use of the selected fuels and fuel types in use during (years of) the last decade in the Netherlands. Special attention has been paid

6 TNO-MEP R 2002/174 6 of 42 to the source of the received emission information and the reliability in qualitative or preferably quantitative terms. This information has been expressed in a CO 2 emission factor for each fuel, possibly accompanied with (an indication of) a confidence interval. This new CO 2 emission factor has been compared with the presently used national CO 2 emission factor and the default IPCC CO 2 emission factor. Also, an indication of the impact of adoption of the new emission factor on the national CO 2 emission has been given for the year According to IPCC, the use of a country specific CO 2 emission factor is to be preferred above the use of IPCC default values. A documentation of the national emission factor is only obligatory in case of a significant difference. Approximately 2% is mentioned as being significant. Only if a difference larger than 2% cannot be explained and documented, the default IPCC value has to be used. In this report, the principle is adopted that all country specific CO 2 emission factors have to be explained and documented, also the ones within a range of 2% of the IPCC default values. It is useful to point out the difference between two IPCC approved methods for CO 2 emission estimation, viz. the Reference Approach and the Detailed Technology based approach (see Appendix A for a more detailed description). The Reference Approach only provides aggregated estimates of emissions by fuel type distinguishing between primary and secondary fuels. The Detailed Technology-based Approach allocates these emissions by source category. The Reference Approach directly uses national CO 2 emission factors, based on either national values or default IPCC values. The Reference approach only distinguishes extracted, imported and exported fuels. This means that secondary fuels that are being converted within the country and remain within the country are not viewed in this approach. For the Netherlands it concerns fuels such as petrocokes, refinery gas, blast furnace gas, cokes gas and chemical residue gas. The large majority of the CO 2 emissions of these fuels are calculated in the Detailed Technology based approach on the basis of a carbon mass balance method or locally measured carbon contents. Thus, national emission factors are not being used for these fuels. The national emission factors for these fuels are used in control calculations and other analyses by scientific institutes.

7 TNO-MEP R 2002/174 7 of Present emission factors and prioritisation 3.1 Interpretation of emission factors Before analysing the set of CO 2 emission factors presently used in the Netherlands, some general remarks on the definition and thus proper interpretation of emission factors in this study have to be made. The CO 2 emission factors assessed in this project are based upon Net Calorific Values and carbon contents, which are related to the composition of fuels. No distinction is made between the different types of fuel use; this means the possible storage of C in a (semi finished) product is not taken into account. This issue is addressed in a separate study on emissions from feedstocks currently conducted by ECN and the University of Utrecht. In the present study, like the IPCC, only CO 2 emissions directly related to the fuel use are taken into account. Indirect effects in terms of upstream losses are not included in the presented emission factors. When fuels are burned, most carbon is emitted as CO 2 immediately during the combustion process. Some carbon is released as CO, CH 4, or non-methane hydrocarbons, which oxidise to CO 2 in the atmosphere within a period from a few days to years. The IPCC methodology accounts for all of the carbon from these emissions in the total for CO 2 emissions 1. CO 2 emission factors in fact concern carbon emission factors. This means that the (differences in) oxidation fractions of carbon in the fuel combustion process are not taken into account in the factor. Or in other words: it has been assumed that the carbon in fuel will completely oxidise during combustion. The different combustion circumstances in locally applied technology are not taken into account in the assessment of emission factors. Also, fixation of carbon in products is not taken into account in emission factors. This IPCC definition of emission factors is followed in this report. However, the complete IPCC methodology does take oxidation and fixation into account. After the estimation of the CO 2 emissions using the carbon emission factors, a correction is made for unoxidised carbon and fixed carbon (see Appendix A for a short overview of the complete IPCC CO 2 methodology). 1 It is important to note that there is an intentional double counting of carbon emitted from combustion. The IPCC format treats the non-co 2 gases as a subset of CO 2 emissions and ensures that the CO 2 emission estimates reported by each country represent the entire amount of carbon that would eventually be present in the atmosphere as CO 2.

8 TNO-MEP R 2002/174 8 of 42 In this report, the number of decimals does not indicate the reliability of a value. In most cases, decimals are being used for presentation purposes and to show the number exactly as it is presented in other literature. 3.2 Overview of present emission factors Table 3.1 shows the default values of the Carbon Emission Factors (CEF) as presented in the Revised 1996 IPCC Guidelines for National Greenhouse Gas Inventories Workbook in ton C / TJ and ton CO 2 / TJ. The latter values are the result of conversion and have been rounded off to 3 significant numbers. The CO 2 Emission Factors presently in use in the Netherlands are also presented in ton CO 2 per TJ. In order to show the relative importance of the emission factors for fuels, the CO 2 emissions of fuels in the Netherlands have been calculated for the year Subsequently, the contribution to national CO 2 emissions is presented for each fuel in terms of the share in national CO 2 emissions. Since the fuel mix did not change drastically over the last years, these figures are expected to give a representative picture of the relative importance of emissions per fuel in the Netherlands and thus indicate the relative importance of high quality emission factors. For all fuels, the CO 2 emission factors presently used in the Netherlands have been applied. This means that the shares do not necessarily reflect the CO 2 emissions as reported in the Common Reporting Format exactly. This approach has been chosen to be able to compare with the situation where IPCC default CO 2 emission factors are used. The last column shows the difference in terms of the relative contribution to the total national CO 2 emission in the Netherlands as a result of the use of IPCC factors instead of country specific emission factors. This indicates the priority on high quality documentation of the particular emission factor Some country specific fuels that are not distinguished by the IPCC are listed at the lower part of the table as non-ipcc fuels. Also, some categories additional to IPCC standard fuel types are being distinguished, for example anthracite for different sectors since in the Netherlands different emission factors are being used for these sectors. In the next paragraphs, the CO 2 emission factors and their foundation will be discussed for each fuel type with reference to table 3.1. After summarising the background of IPCC factors briefly, the Dutch emission factors are being discussed. In a paragraph on prioritisation, a selection will be made of fuel types for which an update of the national CO 2 emission factor is important, considering the criteria as described in section 2. Approach.

9 TNO-MEP R 2002/174 9 of 42 Table 3.1 Overview of default IPCC and Dutch national CO 2 emission factors, contributions to the national CO 2 emissions using national emission factors and the impact of the use of IPCC emission factors. Fuels (translation in Dutch in italic) IPCC CO 2 emission factor [ton C/TJ] IPCC CO 2 emission factor [t CO 2/TJ] Present national EFs [t CO 2/TJ] Share 1998 national CO 2 emission based on present EFs [%] Difference CO 2 emission by national IPCC EFs [%] (c) Primary liquid fuels 1) Crude oil (ruwe olie) (sum 4-18) 1.29 (sum 4-18) 2) Orimulsion (-) n/a 3) Natural gas liquids (aardgascondensaat) n/a Secondary liquid fuels / products 4) Gasoline [for transport] (benzine) [72.3] ) Jet Kerosene (kerosine luchtvaart) ) Other Kerosene (kerosene overig) n/a 7) Shale Oil (leisteenolie) n/a 8) Gas/ Diesel oil [transport] (diesel, petroleum, H.B.O. I en II) [73.3] ) Residual Fuel Oil (zware stookolie) ) LPG [for transport] (LPG) [66.4] ) Ethane (ethaan) n/a 12) Naphtha (nafta) 20.0 (a) 73.3 n/a 13) Bitumen (bitumen) n/a 14) Lubricants (smeermiddelen) 20.0 (a) 73.3 n/a 15) Petroleum Coke (petrokooks) ) Refinery Feedstock s (-) 20.0 (a) 73.3 n/a 17) Refinery gas (raffinaderijgas) 18.2 (b) ) Other Oil (overige olieproducten) 20.0 (a) 73.3 n/a Primary solid fuels 19) Anthracite (steenkool) Anth. Metal industry (st.k. basismetaal) 101 Anth. Other industry (st.k. overige ind.) 94 Anth. Power gen. (st.k. elektr.prod.) 93.8 Anthracite Other (st.k. overige afnemers) ) Coking Coal (kookskolen) ) Other Bit. Coal (bit. kolen) n/a 22) Sub-bit. Coal (subbit. kolen) n/a 23) Lignite (bruinkool) n/a Lignite powder (bruinkoolpoeder) Lignite briquettes (bruinkoolbriketten) Lignite average (bruinkool gemiddeld) ) Oil Shale (-) n/a 25) Peat (turf) n/a Secondary solid fuels 26) BKB & Patent Fuel (briketten, eierkolen) 25.8 (a) 94.6 n/a 27) Coke Oven / Gas coke (kooks) ) Coke Oven Gas (kooksgas) 13.0 (b) ) Blast Furnace Gas (hoogovengas) 66.0 (b)

10 TNO-MEP R 2002/ of 42 Fuels (translation in Dutch in italic) Gaseous fuels IPCC CO 2 emission factor [ton C/TJ] IPCC CO 2 emission factor [t CO 2/TJ] Present national Efs [t CO 2/TJ] Share 1998 national CO 2 emission based on present EFs [%] Difference CO 2 emission by national IPCC EFs [%] (c) 30) Natural Gas, Dry (aardgas, droog) Information entries 31) Solid Biomass (biomassa, vast) n/a 32) Liquid Biomass (biomassa, vloeibaar) 20.0 (a) 73.3 n/a 33) Gas Biomass (biomassa, gasvormig) 30.6 (a) n/a Total IPCC fuels Non-IPCC fuels Chemical residue gases (chemisch restgas) Other solid fuels (overige vaste brandstof) 0.23 TPA Tar, Pitch, Asphalt (teer, asfalt) 1.17 Wood (hout, niet duurzaam) Kerosene / Aviation Gasoline (benzine luchtv.) 0.14 Unknown (onbekend) 0.64 Total Non-IPCC 5.51 TOTAL (a) This value is a default value until a fuel specific CEF is determined. For Gas biomass, the CEF is based on the assumption that 50% of the carbon in the biomass is converted to methane and 50% is emitted as CO 2. The CO 2 emissions from biogas should not be included in national inventories. If biogas is released and not combusted, 50% of the carbon content should be included as methane. (b) For use in the sector calculations. (c) The difference in CO 2 emission shares as a result of the use of IPCC default EF instead of national EF is calculated by the formula IPCC EF ( 1 ) * share 1998 national CO 2 emission national EF 3.3 Sources and quality of present IPCC EFs The IPCC Reference Approach relies primarily on the emission factors from Grubb (1989) with additions from other studies, to estimate total carbon content. The suggested carbon emission factors are listed in table 3.1. The carbon emission factors for the fuels are average values based on net calorific values (NCV). This approach has been recommended by the IPCC because it reduces the variation in carbon content by weight and enables the comparison of different fuels in terms of their use in terms of producing energy. The approach used by Grubb to estimate carbon emission factors is very similar to Marland and Rotty (1984), but based on more recent research. All carbon emission factors were originally reported on a gross calorific value basis, but are converted by Grubb to a net calorific value basis. He provides carbon factors for methane, ethane, propane, and butane and using data from Marland and Rotty (1984), estimates an average emission factor for natural gas of 15.3 t C/TJ +/- 1 per cent. It is

11 TNO-MEP R 2002/ of 42 based upon samples of natural gas representing the average natural gas in For oil and some refined petroleum products the estimates are based on literature data. The carbon emission factor of coal, excluding anthracite, was defined as: EF = * Hv where EF is the carbon emission factor in t C/TJ and Hv is the gross calorific value of the coal when the calorific value is from 31 to 37 TJ / kiloton on a dry mineral matter free (dmf) basis. Anthracites fall outside this range and a value of 26.8 t C/TJ or 98.3 ton CO 2 /TJ is used. Since the publication of the original OECD Background Document (OECD 1991), additional information has been made available on carbon emission factors. At an IPCC sponsored workshop in October 1992 (IPCC/OECD, 1993), experts recommended several revised emission factors based on national inventory submissions to the OECD. Additional emission factors were also made available based on the work of the expert group on GHG Emissions from Fuel Combustion during Phase II of the IPCC/OECD/IEA Programme on National GHG Inventories in Sources and quality of present national EFs The CO 2 emission factors presently in use in the Netherlands for different types of fuels are based on different publications. Per fuel type the scientific foundation and source of the EF will be discussed in order to estimate the quality and validity of the national EF Solid fossil fuels (primary and secondary) Primary solid fuels The CO 2 emission factor for coal can vary over a wide range according to the type of coal. In the Netherlands all coal is being imported. This means that it is not easy to assess the typical coal that is being used in the Netherlands. The types of coal are being differentiated to types of consumers or sectors. Different types of anthracite and thus different emission factors are therefore used for different sectors in the Netherlands. The main consumers of anthracite are the power companies (approximately 25 Mton CO 2 ) and the iron & steel industry (Corus, responsible for CO 2 emissions in the order of 5 Mton). The latter also exports self-produced cokes in significant amounts (in the order of 1 Mton CO 2 ). In 1988 van der Kooij [KEMA] presented an analysis of 55 hard coal samples representing coal used in Dutch power stations over the period He showed

12 TNO-MEP R 2002/ of 42 that the variation in carbon content was correlated to the net calorific value (NCV in MJ / kg) as follows: C-content (mass %) = 2.35 * NCV Since: EF [ton C / TJ] = C-content (mass %) / 100 NCV [MJ / kg] / 1000 this can be reformulated into: EF [ton C / TJ] = ( 2.35 * NCV ) NCV [MJ / kg] / 10 or: EF [ton C / TJ] = / NCV Since the average net calorific value was 26.9 MJ / kg at that time, the CO 2 emission factor was 93.8 ton / TJ. This relation is graphically presented in figure 3.1 where the square indicates this average situation. Also, the relation found by Grubb for the IPCC and the IPCC EF for coal as described in the previous paragraph, are depicted in the figure.

13 TNO-MEP R 2002/ of 42 NCV [MJ/kg] Coking coal / Other bit. Coking coal / Sub-bit. IPCC 25 Dutch coal Anthracite CO2 emission factor [ton/tj] Figure 3.1 The relation between net calorific value and the CO 2 emission factors based upon 55 hard coal samples representing coal consumed in Dutch power stations from 1981 to 1988 [van der Kooij KEMA 1988] and the analysis for the IPCC by Grubb 1 [Grubb, 1989]. The CO 2 emission factor of 93.8 is used in a rounded form for the industry, except for the iron & steel industry. The iron & steel industry used a factor of 101 ton/tj for its metallurgical coal. This is reported in Okken (1989) but the basis is unclear. To our knowledge, this emission factor has also been used for cokes. The anthracite combusted in households had an average carbon content of 90% according to the Note on Coal (in Dutch Kolennota, Appendix C, Dutch Parliament ). Assuming a net calorific value of 32 MJ / kg, a CO 2 emission factor of 103 ton / TJ was calculated. These values are not very accurate, but the present use of coal in households is very limited. The emission factors of lignite powder (Building materials) and lignite briquettes have been based on an analysis by Rheinische Braunkohlenwerke (Koln) in The emission factor for lignite powder is and for briquettes ton CO 2 / TJ. The average value is 101 ton CO 2 / TJ. The use of lignite is very limited in the Netherlands. In 1998 only in the sector industry (building materials, pottery and glass) and the building sector (extraction of other non-energy carriers) a limited amount of 132 TJ brown coal is used, resulting 1 Assuming a factor 0.93 between Gross Calorific Value and Net Calorific Value.

14 TNO-MEP R 2002/ of 42 in 14 kton CO 2. Since this is negligible in the national balance, it is not investigated further. Coke oven gas and blast furnace gas On the basis of data of the PER of individual companies ( ) an emission factor for blast furnace gas of 200 ton CO 2 / GJ and for coke oven gas of 44 ton / TJ was adopted. The composition of especially blast furnace gas can vary substantially Liquid fossil fuels (primary and secondary) Crude oil The estimation of the CO 2 emission factor for crude oil is based upon estimation by Olivier et al. (2000) that did not include measurements. The national CO 2 emission as calculated by the Reference approach, serving as a control calculation, uses the crude oil emission factor. A sensitivity analysis has been executed for four (hypothetical) sets of carbon contents for crude oil, showing that the national emissions may vary on average over the last 10 years with 1.6%. The Reference calculation is quite sensitive to the emission factor for crude oil since the amounts of crude oil being refined in the Netherlands are high due to the high export of oil products. It should be noted here that the national CO 2 emission estimation following the bottom-up method is not relying on the crude oil emission factor. Liquid oil products On basis of the composition of crude oil ((CH 2 ) n ) and the literature consulted (a.o. Polyenergy-pocketbook (in Dutch)) the amount of carbon is estimated to be 85.7% (which is exactly the carbon content of the heavier alkanes n>200). Net calorific values of 41 GJ / ton for residual fuel oil, 42 to 43 GJ / ton for lighter oil products such as gas and diesel oil, and 44 GJ / ton for gasoline and kerosene have been assumed. On this basis, the following emission factors are calculated: for residual fuel oil 77 kg CO 2 / GJ, for lighter products 73 to 74 (to be exact 73.3) ton CO 2 / TJ and for gasoline and kerosene 72 (to be exact 72.3) ton / TJ [Spakman et al., 1997]. The value of residual fuel oil is also used for Tar, Peat and Asphalt. Since the fuel composition of gasoline, kerosene and gas/diesel oil can vary substantially, one emission factor of 73 kg CO 2 / GJ has been chosen. However, for calculation of emissions in the transport sector, the exact values with one decimal are being used (presented within brackets in table 3.1). This is reported in Klein et al. [2002]. LPG In 1987, the composition mentioned in the Polyenergy-pocketbook was according to Okken [Okken et al. 1989] 58% propane, 27% butane, 10% propene and 5% butene, resulting in a corresponding emission factor of 65.6 g/mj. On basis of literature consulted (a.o. Polyenergy-pocketbook (in Dutch)) the amount of carbon in LPG is estimated to be 82%. The net calorific value is estimated to be 45 46

15 TNO-MEP R 2002/ of 42 GJ/ton (based on the same literature). This leads to an emission factor of 66 kg CO 2 /GJ [Spakman et al., 1997]. Like with diesel and gasoline, the exact value of 66.4 is being used in the emission estimation for transport only (Klein et al. [2002]). It is not known how country specific these values are. Refinery gas and chemical residue gas On basis of some samples of chemical residue gas and refinery gas taken during the data collection in the framework of the PER ( ) an emission factor of 46 kg CO 2 / GJ was calculated. The composition of these gases can vary a lot (ranging from high CO 2 contents to high hydrogen contents), therefore, the emission factor of 46 kg CO 2 / GJ is probably not robust over the years. Petroleum Coke Petroleum coke is a black solid residue feedstock, obtained mainly by cracking and distillation of crude oil. Except for the production of silicium carbide, petrocoke is used as an intermediary fuel in the cracking process. The compositions of petroleum cokes highly depend on feedstock and types of processes used. In general petroleum cokes contain some portions of all the elements, which existed in the original feedstock. This emission factor for the Netherlands is based on the assumption that the petroleum cokes contain 99% carbon, diminished with 5% of hydrogen. This leads to an emission factor of 100 kg CO 2 /GJ Gaseous fossil fuel The natural gas from Dutch origin is being excavated and purified by the Dutch Petroleum Company (NAM) and sold to the N.V. Nederlandse Gasunie, which was the sole gas trading and transmission company in the Netherlands before the recent gas market liberalisation. The presented emission factor of 56 ton CO 2 / TJ for natural gas is based upon measurements by Gasunie of the gas quality from different gas wells in the Netherlands. One national average value has been calculated for the different gas qualities in order to avoid a situation where natural gas consumers have to monitor the composition of the consumed gas. This mean value is accurate up to a range of plus or minus 1%. Although the measurements took place more than 20 years ago, the data are still valid according to Gasunie [Personal communication K. Dijkstra of Gasunie].

16 TNO-MEP R 2002/ of Priority setting Priority setting is based upon the contribution to the Dutch national emissions, the quality and age of the present documentation as well as the expected sources and quality of possible new information. Furthermore the amount of deviation from the IPCC standard EF is taken into account. A quick look at table 3.1 learns that the combustion of natural gas, anthracite (including coking coal) and gas/diesel oil and gasoline deliver the most voluminous contribution to the total Dutch emission of CO 2. Together, these sources account for almost 90% of national CO 2 emissions. For the CO 2 Reference approach, the contribution of crude oil is very important as well. Adoption of the default IPCC emission factor for anthracite (including coking coal) would theoretically lead to an increase of national CO 2 emissions of 0.69%, which is a relatively large proportion given the limited share of coal in the national balance (15%). The choice for the default set of IPCC CO 2 emission factors for several light oil products would decrease national emissions with only a small proportion of 0.3%. However, the distribution over different fuel types and sectors is quite different when IPCC values are used. Adoption of the IPCC value for natural gas will hardly affect national emissions (0.089%) because the values of the national emission factor and the IPCC emission factor are close together. Nevertheless, the investigation of the emission factor of natural gas receives priority since natural gas accounts for half the CO 2 emissions in the Netherlands. Theoretically, a large impact can be expected from the shift towards the IPCC default CO 2 emission factors for refinery gas and blast furnace gas. National emissions would increase with more than 1.5% respectively almost 0.2%. However, in practice, these emission factors are not used for the national emission inventory, since the refineries and iron & steel company deliver their emissions based upon a carbon balance calculation. In fact, also the emission factor for coal is not used for the national inventory since the central purchasing office for the electricity companies (Gemeenschappelijk Kolenbureau Elektriciteitsproductiebedrijven) has measured the carbon content and heating value of the coal purchased for the power companies annually. Adoption of the default IPCC CO 2 emission factors would therefore only in theory lead to an increase of 2.3% of present CO 2 emission estimations in the Netherlands. This would only be the case if all parties presently submitting their CO 2 emission estimations to the national PER used the presented national set of CO 2 emission factors. However, if CO 2 emissions that are estimated without the use of a national

17 TNO-MEP R 2002/ of 42 emission factor, are left out of the comparison, the impact of using default CO 2 emissions would be a decrease of 0.2%. This is current practice. Based upon the previous discussion, it was agreed upon in discussion with the project group CO 2 monitoring that natural gas, anthracite (including coking coal) and gas/diesel oil and gasoline (oil products and crude oil) deserve specific research, analysis and documentation. This is presented in the next section 4. Analysis of new information on fuels. In addition, other fuels are sometimes discussed with respect to aspects such as the application of the national emission factor.

18 TNO-MEP R 2002/ of Analysis of new information on fuels In the following paragraphs new information is presented, analysed and compared with the presently used EF of the Netherlands and IPCC. The focus is on the most important fuels with respect to CO 2 as selected in the previous section. After a short introduction concerning the application of the fuel, the new information regarding the EF is discussed and eventually expressed in the form of a possible new EF. After this a comparison is made between the IPCC, the old and the new emission factor. This comparison includes the implications for the emission of CO 2. Finally, recommendations for the improvement of the quality or accessibility of information are made. Before this fuel specific analysis, a general discussion of the requirements for consistent CO 2 emission calculation is presented. It concerns the consistent application of CO 2 measurements, emission factors, emission calculations and procedures for the adoption of national CO 2 emission factors. 4.1 Consistency of CO 2 calculations Measurements and factors A CO 2 emission factor as defined by IPCC in terms of ton CO 2 per TJ of fuel cannot be measured directly. In fact, the carbon content (in weight %) has to be measured or calculated from the chemical composition. Furthermore, the heating value (in terms of Net Calorific Value, NCV) is necessary to express the amount of fuel in terms of energy instead of mass. Preferably, the assessment of a national emission factor would consist of an accurate combined measurement of a representative sample of fuels in terms of both carbon content and heating value. However, this is only the correct approach if it is consistent with national statistics. The units to measure amounts of fuels in Dutch statistics are not energy units. Natural gas is measured in standardized m 3 of gas (at 0 C and 1013 mbar), coal and oil products in weight units (ton). The conversion to energy units is performed with standard conversion factors. Up to now, the exception is coal, from which the heating value was measured each year by GKE. However, due to the electricity market liberalisation, GKE will stop per 1 July 2002 the central purchase of coal for the electricity production companies. It is not clear who will measure the coal quality in the future and if these data will continue to be available.

19 TNO-MEP R 2002/ of 42 The use of standard conversion factors has as a consequence that changes in energy consumption due to changes in calorific values are not registered in the national energy statistics. In relation to this, making changes in a national emission factor as a result of a change in calorific value over time introduces an error in the national emission estimation. The only way to avoid both limitations is to use the real (annually measured) heating value in both emission factors and national statistics. As long as the national statistics do not use the actual heating values, national emission factors should preferably be calculated using the standard conversion factors as being used in national statistics in order to calculate the correct national emission. The same holds for local application of the national emission factor. If the local energy consumption has been calculated with a locally measured heating value, the use of a national emission factor in terms of ton CO 2 per TJ results in wrong CO 2 estimations. In fact it means that in this situation as in the Netherlands, the carbon content is the most accurate, measurable indicator of CO 2 emissions, combined with data on the amount of fuel. Therefore, it is recommended that the presentation of CO 2 emission factors in terms of ton CO 2 per TJ (as recommended by IPCC) is supplemented with carbon contents (weight %) and perhaps standard national net calorific values as used in the national statistics in order to make the background of CO 2 calculations transparent and facilitate the proper application of emission factors. In the early eighties, when the first set of Dutch emission factors were adopted, it has been chosen to adopt rounded numbers since this was in accordance with the uncertainty of the numbers. However, it appears that there is a tendency among institutes or companies to use more accurate numbers, maybe as a result of an increasing importance of CO 2 emissions within the Netherlands. For instance the CO 2 emissions of the transport sector are being calculated with the EF values with one decimal. This is reported only recently in Klein et al. (2002). It is concluded that the present set of emission factors and the application of it is not transparent. Therefore it is recommended to use numbers with one decimal that will be used by all parties. In addition to this, it can be concluded that thorough communication on the good and consistent application of the set of national emission factors is of high importance. Therefore the recommendation is made to draw up a set of guidelines that accompany the set of CO 2 emission factors on the proper application of these factors. This last updated version of this set of emission factors, as well as the guidelines, should be communicated broadly. An Internet site is a highly suited way to realise this Criteria for adoption of new CO 2 emission factors After analysis of new information and literature sources, eventually leading to a proposition for different value of the CO 2 emission factor, it still remains to be decided whether the national emission factor will be updated or not. In other words,

20 TNO-MEP R 2002/ of 42 what criteria for adoption of (new) CO 2 emission factors have to be used? It is recommended to adopt explicit criteria for adoption of national CO 2 emission factors. The IPCC states in its guidelines that in case a national emission factor has a weak foundation or is based upon obsolete information, the IPCC default value has to be adopted while in the other cases the national value is preferred. According to IPCC, only differences larger than 2% between the national and the default IPCC emission factor have to be explained by documentation. It is the view of the authors that deviations within a range of 2% of the default IPCC value also have to be explained. This procedure is more correct since unsubstantiated adjustments downward are being avoided. In other words, all national emission factors have to be documented. If the new data lead to an insignificant adjustment of the emission factor, the factor presently in use will be kept. Here, an explicit decision has to be made on the deviation that is being considered as insignificant. Given the different properties of fuels and the different uncertainties ranges attached to the emission factors of fuels, this adjustment range can be very well fuel specific. Furthermore, in our opinion it is practical not to change emission factors to often. The resulting emission estimation will be more consistent and probably more accurate. In case of a methodological change or drastic variation over time of the CO 2 emission factor, recalculation has to take place for historic time series. Recalculation is not presented in the present report. 4.2 Primary solid fossil fuels Introduction The main consumers of anthracite are the electricity companies and the metal industry (Corus) that produce CO 2 emissions in the order of 25 Mton respectively 5 Mton CO 2. The electricity companies obtained their anthracite from GKE (NV Gemeenschappelijk Kolenbureau Electriciteitsproduktiebedrijven) a central purchase office which supplied from 1987 to 2000 all coal used for electricity generation by the Dutch generating companies. It concerned coal from 6 different continents. From 2001, EON (former EZH) and Electrabel Netherlands (former Epon) withdrew from the central purchase after market liberalisation. Per 1 July 2002, GKE will stop the central purchase of coal. Thus, in the future, information on the national coal quality is only available at the power companies themselves. Because of the increased market competition, it is very well possible that this information is less freely available than in the past for the whole sector.

21 TNO-MEP R 2002/ of 42 Corus Steel (IJmuiden) uses anthracite (metallurgical coal, also called coking coal) for the production of pig iron and imports anthracite from five different countries (USA, Canada, Australia, Poland and Venezuela). A part of the coal is transformed into cokes and cokesoven gas. The cokes are exported in significant amounts (several tenths of Mton CO 2 ) and the blast furnace gas is sold in amounts equivalent to 1 Mton CO 2 to an external power plant (UNA). Results Power generation The Technical Laboratory Rotterdam takes over 1000 samples annually from coal supplied to power generation in the Netherlands and analyses the coal with respect to calorific value and carbon and sulphur content (among other things) [source: Breman of GKE]. The information provided by the GKE is presented in table 4.1 and 4.2. The last two columns in table 4.1 present the emission factors for CO 2 and SO 2 respectively, assuming that all carbon and sulphur are oxidised. The data on carbon content and thus CO 2 emission factors are only available for the last 3 years. However, we used the relation between carbon content and lower heating value that has been assessed for Dutch coal in the eighties by van der Kooij [KEMA, 1988] to estimate the 1990 carbon content (see also section 3). The standard deviation of the individual carbon content measurements of the last year was 4.2%. Assuming a standard normal distribution, it can be concluded that the 95% confidence interval of the mean carbon content with 1270 samples is +/- 0.4% or a carbon content ranging from 62.4 to 62.9%. The standard deviation of the sulphur content is 1.1%, resulting in a 95% confidence interval of the mean sulphur content of +/-6.7% or a sulphur content ranging from 0.84 to 0.96%. Looking at all the data on the quality of coal used in power generation, a switch to lower quality coal can be observed over the last decade. In 1990 the net calorific value was considerably higher while the sulphur content was lower compared with the coal used in One of the reasons is that the abatement technology available is effective in terms of removal efficiency and costs to meet SO 2 emission standards and allows for the purchase of cheaper coal. However, the CO 2 emission factor does not follow this development directly. The emission factor merely jumps up and down in a margin around the average value. This is illustrated in figure 4.1, where the relation of van der Kooij on coal of the eighties, our assumption to apply it also on 1990 and the values of GKE for the period are presented together in one graph. Clearly, it can be seen that the emission factors of the last years are placed in a range next to the van der Kooij relation. Or to put it in other words, the relation assessed by van der Kooij is not applicable at the end of the century because the coal quality and mix has changed completely. The annual fluctuation of the emission factor is sometimes more than the 0.4% deviation of the carbon content.

22 TNO-MEP R 2002/ of 42 The changes in coal are illustrated once more in table 4.2 that presents for each supplier country the shares in total coal supply to the Dutch power generation from 1990 to The table clearly shows that over the last decade South Africa and Indonesia have taken the place as major coal supplier from Australia and USA. Table 4.1 The quantity, quality and CO 2 and SO 2 emission factors of coal supplied to the Dutch power generation sector over the years, under the assumption that oxidation of C and S is complete and not taking into account end-of-pipe abatement technology [source GKE / TLR]. Year Supply C-content S-content Net calorific value CO 2 emission factor SO 2 emission factor [PJ] [mass-%] [mass-%] [MJ/kg] [ton CO 2/TJ] [ton SO 2/TJ] n.a n.a The carbon content has been derived with the formula by van der Kooij [KEMA 1988] assuming the coal quality and mix in 1988 was similar to those of 1990 (see also figure 4.1). C-content [mass-%] NCV [MJ/kg] CO2 emission factor [ton/tj] Figure 4.1 The CO 2 emission factors of Dutch coal for the power generation in [GKE 2001] presented in combination with the relation between carbon content and net calorific value resulting in CO 2 emission factors based upon 55 hard coal samples representing coal consumed in Dutch power stations from 1981 to 1988 [van der Kooij KEMA 1988]. 20

23 TNO-MEP R 2002/ of 42 Table 4.2 The shares in total coal supply to the Dutch power generation presented by supplier country from 1990 to 2000 [source: GKE]. Supplier country Share of total supply USA Australia Colombia South Africa Indonesia Poland China 1 4 Other Total As has been explained in section 3.1 Interpretation of emission factors, the CO 2 emission factors here are in fact carbon emission factors, assuming full combustion of carbon. After calculation of gross CO 2 emissions, a correction has to be made for unoxidised carbon in e.g. fly and ground ashes. The reader is referred to Appendix A. In this respect it is interesting to mention the use of biomass (wood chips) in coal fired power plants which is one of the measures to reduce CO 2 emissions in the Netherlands. Although the CO 2 emission factor of this wood is assumed to be 0 (since this wood is produced under sustainable conditions), the influence of biomass on the combustion of coal is not known. In this study it is assumed to be negligible. All new coal fired power stations in the Netherlands are fitted with flue gas desulphurisation units using the wet gypsum process. In this process limestone (CaCO 3 ) is used as flue gas desulphurisation agent. During this process CO 2 is generated: CaCO 3 + SO 2 -> CaSO 4 + CO 2 This means that for each molecule of removed SO 2 one molecule of CO 2 is generated [Okken, ECN 1989]. Since the ratio of molecular masses of CO 2 and SO 2 is 44/64.1, the emission of ton SO 2 / TJ in the year 2000 results by flue gas desulphurisation with an efficiency of 90% into the following: Additional CO 2 emission factor = * 44/64.1 * 0.90 = 0.46 ton / TJ Accordingly, the coal with lower sulphur content in the year 1990 had a lower additional CO 2 emission factor due to flue gas desulphurisation of 0.3 ton / TJ. 1 Other countries are among others Russia, Venezuela, The Netherlands, Belgium, Germany, Spitsbergen, Egypt, Nigeria and New Zealand.