BIOETHANOL GREENHOUSE GAS CALCULATOR - HGCA

18kg of nitrogen fertilizer (as N) applied. Very recent work appears to challenge thisassumption, particularly in cooler temperate climates and further work is required toclarify the N 2 O emissions methodology.Table 3: Effects of straw removal on fertilizer requirementsFertilizer application, kg/haFertilizer type all straw ploughedbackall straw removedN fertilizer (as N) 185 253P fertilizer (as P) 41 53K fertilizer (as K) 46 164In the Calculator, selection of either of the option buttons for “straw ploughed in” or“straw removed” has no effect on calculations other than through enabling adjustmentof fertilizer application rates for the default cultivation conditions (as per Table 3) viathe “Set Default Values” button. In a wheat-to-ethanol GHG calculator, it would beuseful to be able to accept input data on the fate of straw and use this directly incalculations of nitrous oxide emissions from the land as well in calculations of creditsfor use of straw for purposes other than fuel for the bioethanol plant. However, thiswould require more information than is currently readily available. As indicatedabove, precise estimates of the effects of removal of different amounts of straw fromthe field on N 2 O emissions require better models of the N 2 O emission processes. Forcalculations of GHG emissions credits for straw, the amounts of straw removed, theuses to which it is put, and the GHG emissions associated with the displaced products,would have to be known. Site specific soil and climate information may also beimportant factors in estimating N 2 O emissions.5.4 Fossil Fuels and ElectricityFor all consumption of fossil fuels and electricity from the grid, the GHG emissionfactors shown in Table 4 are used.Table 4: GHG emissions factors for fossil fuels and electricityGHG Emissions(kg CO 2 eq/GJ)Diesel 87.4Gasoline 85.8Natural Gas (EU-mix) 61Grid Electricity (UK-mix) 1605.5 TransportCalculations of GHG emissions resulting from transport of wheat feedstock, strawfuel and ethanol product are based on the GHG emissions factors shown in Table 5.