Use of Models and Facility-Level Data in Greenhouse Gas Inventories

More documents

Recommendations

Info

Use of Models and Facility-Level Data in Greenhouse Gas Inventories methane is allocated to industrial sites). Table 2-2 shows the total emissions from gas-fired power stations in the five data sets. Table 2-2 Emissions for gas-fired power stations (ktonnes CO 2) Gas-fired power stations IPPC regulatory inventories CITL GHG inventory 59,250 59,154 58,564 As with coal/oil-fired power stations, there are relatively small differences between the data. The CITL figure is slightly lower than the figure given in the regulators’ inventories, although a number of very small power stations do not report in these inventories, so one might expect the CITL figure to be the higher of the two. The reason why this is not so is not clear but it is most likely due to small differences in scope at some installations, or due to inconsistent reporting. A detailed analysis has been made (but not reported here) of site-specific data for those gas-fired power stations where there was least good agreement between the various data sets. The analysis suggests that the CITL data is more reliable that the data taken from regulators’ inventories. 2.1.4 Integrated steelworks According to the 2007 UK GHG inventory, integrated steelworks and coke ovens emitted 4% of UK carbon in 2007. The UK has three integrated steelworks which incorporate coking, sintering, blast furnaces and steel production using the basic oxygen process. These steelworks are owned by Corus. It is necessary to add the UK’s only remaining standalone coke ovens (operated by Monckton Coke & Chemical) to this group in order to ensure a more consistent scope in the various data sets. Table 2-3 shows the total emissions from steelworks and coke ovens reported in the various data sets. Table 2-3 Emissions for integrated steelworks (ktonnes CO 2) Integrated steelworks IPPC regulatory inventories CITL Corus GHG inventory 21,776 20,486 21,677 21,355 The agreement between the total emissions from the CITL and the GHG inventory is reasonable. There are considerable differences between the emissions totals from different sub-sources; however there are some factors that help to explain at least some of these differences. Generally, these are to do with the scope of the estimates. The figures from the regulator’s inventory and from Corus are believed to cover all or at least the most significant sources of carbon emissions at each site. The main difference between the two is then the inclusion of Monckton’s coke oven in the Pollution Inventory data but not included in the Corus data. The site-specific data are actually somewhat different in the case of two Corus sites but these largely cancel out in the totals. These differences are thought to be due to changes in methodology between reporting to the Pollution Inventory and the later compilation of the Corus data set. The CITL data do not include emissions from rolling mill furnaces and reheat furnaces, whereas the Pollution Inventory and Corus data do, therefore the CITL figure is lower. The GHG inventory estimate is based on national activity data and emission factors and will not necessarily be consistent with the non-GHG inventory data sets. But the level of agreement with the Corus and regulator’s inventory is good. There is one area where the scope of the estimates may be slightly different – the GHG inventory groups all iron & steel industry use of fuels in boilers and furnaces together and this fuel use will include fuel used at Corus’ integrated steelworks, Corus’ other works, and fuel used by numerous other process operators, most of them running small foundries. In this analysis we have included all emissions from use of coke oven gas and blast furnace gas in the figure IPCC Expert Meeting Report 80 TFI
Use of Models and Facility-Level Data in Greenhouse Gas Inventories shown in Table 2-3, but excluded all emissions from coke, fuel oil, natural gas, and other, minor, fuels on the basis that the majority of usage is likely to be at other sites. Some natural gas and fuel oil may actually be used at the integrated works, so the GHG inventory figure would then underestimate actual emissions. Table 2-4 compares data from Corus and from the GHG inventory, broken down by emission source. The difference in the figures for basic oxygen furnaces stands out as the most significant discrepancy between the two sets of data. The difference is at least partly explained by inconsistencies in the scope. The GHG inventory figure only covers carbon dioxide derived from dolomite added to the oxygen furnace, and electrode emissions in ladle arc furnaces. The Corus figure also includes emissions from casters, ladle heating and, perhaps most importantly, emissions from oxygen blowing. In the GHG inventory these are treated as part of the overall carbon balance and so the carbon contained in the basic oxygen furnace-off gas is treated as entering the steelworks fuel gas supply and then emitted from the coke ovens, blast furnaces and combustion plant (with some possibly being included in the flaring/losses figures). A more detailed breakdown from Corus would help to determine whether the discrepancy noted is solely due to differences in scope or whether there is a serious problem with one or other set of data. Table 2-4 Emissions for integrated steelworks, broken down by source type (ktonnes CO 2) Data by source Source Corus GHG inventory Coke ovens 1,206 1,320 Sintering 2,988 2,977 Blast furnaces 4,495 4,631 Basic oxygen furnaces 1,547 136 Flaring/losses 1,613 2,127 Combustion 9,827 10,168 Given the issues outlined above for the basic oxygen furnace numbers, it is not possible to draw any conclusion from the much smaller differences between the GHG inventory and Corus figures for the other sources, although the GHG inventory figure for coke ovens does contain emissions for Monckton and therefore should be larger than the Corus figure. An important question to answer is is it possible to use the detailed ETS data to identify the emissions from combustion alone in this sector? For the UK it is not possible to isolate combustion emissions from the whole iron and steel sector; it is possible to identify combustion emissions from coke ovens and sintering processes, but not from blast furnaces 13 . Table 2-5 shows total emissions data for individual installations. Table 2-5 Emissions for integrated steelworks & cokeovens (ktonnes CO 2) Data by site Installation Regulators’ inventories CITL Corus Corus Port Talbot 7,348 7,058 7,557 Corus Scunthorpe 8,081 7,172 7,828 Corus Teesside 6,299 6,211 6,296 13 In Table 2-4, based on the way we report emissions in the UK GHG inventory, the coke ovens line will mainly be 1A1c, but with possibly some emissions from 1B1b, the blast furnace line will cover 1A2a but also 2C1, but the combustion lines will be solely 1A2a. The remaining lines are not combustion. IPCC Expert Meeting Report 81 TFI
Page 1:
Use of Models and Facility-Level Da
Page 4 and 5:
Supporting material prepared for co
Page 6 and 7:
Page 8 and 9:
Page 10 and 11:
Page 12 and 13:
Page 14 and 15:
Page 16 and 17:
Page 18 and 19:
Page 20 and 21:
Page 22 and 23:
Page 24 and 25:
Page 26 and 27:
Page 28 and 29:
Page 30 and 31: Use of Models and Facility-Level Da
Page 130 and 131:
Page 132 and 133:
Page 134:
show all

Use of Models and Facility-Level Data in Greenhouse Gas Inventories

Create successful ePaper yourself

Delete template?

Save as template?