BIOETHANOL GREENHOUSE GAS CALCULATOR - HGCA

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20As in the LCVP study, imported soya bean meal from the USA is chosen as theanimal feed product that is substituted by DDGS in calculations of animal feedcredits. Future versions of the Calculator would allow for a choice of different animalfeed products substituted, but currently only limited data is available on lifecycleGHG emissions from production of other animal feed products that may be displacedby DDGS. Each kilogram of DDGS is considered to substitute for 0.78 kg of soyabean meal, on the basis of relative protein content (Concawe, 2003). Production in theUSA and transport to the UK of each kilogram of soya bean meal result in emissionsof 0.46 kg CO 2 eq.For DDGS used as fuel in co-firing for electricity production, a credit of 945 kgCO 2 eq per tonne of DDGS is applied. This is based on the assumptions that:• DDGS (10% moisture) has a lower heating value of 18.2 GJ/t, the same aswheat grain on a dry basis.• DDGS is converted to electricity at the UK average rate of 0.325 gigajoule ofelectricity output per gigajoule of primary energy input.• The electricity generated from DDGS substitutes for other electricitygeneration with GHG emissions equal to the UK average of 160 kgCO 2 eq/GJe (Table 4).It may be argued that electricity generated by the cofiring of DDGS with coaldisplaces marginal coal-based electricity generation, and that the calculations of GHGemission credits should be based on this coal-derived electricity rather than the UKgrid average. This will need to be considered in future versions of the Calculator.5.6.2 Surplus electricityAny surplus electricity produced by an ethanol plant (that is, any electricity that isgenerated but not used by the plant) is assumed to displace generation of an equalamount of grid-supplied electricity with GHG emissions equal to the UK electricitygeneration average of 160 kg CO 2 eq/GJe, and this value is used to calculate creditsfor those ethanol production chains which include generation of surplus electricity.5.6.3 Set-aside, carbon dioxide and strawIn the Calculator, all wheat for ethanol production is assumed to be grown onrotational set-aside, and a credit of 922 MJ/ha (equivalent to 25.8 l/ha of diesel fuel) isapplied for avoidance of maintenance of set-aside land.As discussed in section 5.3 above, no credits are assigned for straw not used as fuel inthe ethanol plant. Similarly, no credits are assigned for any carbon dioxide by-productthat may be captured from the wheat-to-ethanol fermentation process. Most of thecarbon dioxide that is produced and sold industrially originates as a by-product ofother industrial operations, and if this CO 2 was not captured, it would be vented toatmosphere. Thus, CO 2 capture from bioethanol production would not result in a netdisplacement of CO 2 emissions. If carbon dioxide is captured and stored indefinitely,then a CO 2 credit would be appropriate. Future versions of the Calculator maytherefore need to include such a credit.
216. Default Bioethanol Production ChainsIn order to illustrate typically expected inputs, yields and resultant GHG emissions ofdifferent bioethanol production chains, the Data Input Page of the Calculator providesthe option to accept the input data adopted by the LCVP experts for each of the mainsections of the production chain by clicking on an associated “Set Default Values”button. These default process characteristics are described below.6.1 Basic wheat-to-ethanol pathwayThe values adopted by the LCVP study for the basic non-energy inputs and yields ofthe different processes in the bioethanol production chain are shown in Figure 10.0.081 t SeedWheat production and supplyJCULTIVATION AND HARVESTING0.437 ha1.424 tstraw3.499 t wheat(16% moisture content)DRYING AND STORAGE3.03 t dry wheat grain(3% moisture content)TRANSPORT (road)Ethanol productionMILLING10 twaterHYDROLYSIS AND FERMENTATION0.913 tCO210 t alcohol (10% ethanol)+ 1.14 t solidsDISTILLATIONDRYING1.14 tDDGS1.058 t distillate(94.5% ethanol)9.942 twaste waterDEHYDRATION1 t bioethanolFigure 10: Basic assumptions for default wheat to ethanol pathways (LCVP, 2004)
Page 1 and 2: BIOETHANOL GREENHOUSE GAS CALCULATO
Page 3 and 4: Table 2: GHG emission factors for f
Page 5 and 6: 11. IntroductionA recent lifecycle
Page 7 and 8: 3recovery (LCVP report; Rickeard et
Page 10 and 11: 64. Using the CalculatorThe bioetha
Page 12 and 13: 8DATA INPUT GUIDANCEThe table below
Page 14 and 15: 10PRE-PROCESSING(DRYING AND STORAGE
Page 16 and 17: 12• Surplus electricity (kWh/t et
Page 18 and 19: 14Clicking the BACK button takes th
Page 20 and 21: 165. Underlying factors and calcula
Page 22 and 23: 18kg of nitrogen fertilizer (as N)
Page 26 and 27: 226.2 Farming Inputs and YieldsFor
Page 28 and 29: 247. ReferencesBauen, A., Howes, J.
Page 30 and 31: 26Definitions and terminologyThe fo
Page 32 and 33: 28Climate Change (UNFCCC definition
Page 34 and 35: 30Kyoto Protocol is the Protocol, d
Page 36 and 37: 32continued supply depends, in many
Page 38: 34In this case ‘delivery’ is as

BIOETHANOL GREENHOUSE GAS CALCULATOR - HGCA

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