The greenhouse gas emissions performance of cellulosic ethanol supply chains in Europe

Table 7 Emission factor parameters included in the sensitivity analysis.

Parameter	Unit	Base-case value.unit^-1	% Variation relative to base-case		Remark
			Min	Max
Softwood production transport and size reduction		46.0	0.5	1.9	Range reflects the difference between high and low estimates for softwood emissions, excluding land-use change
	kgCO₂e.odt^-1
Straw production and transport		2.6	0.5	2	This range is illustrative only and reflects variation around the lower estimate for straw
Enzyme production	kgCO₂e.kg protein^-1	9.55	0.1	1.4	Range reflects the carbon intensity of enzyme manufacture using Swedish or UK electricity relative to EU 27
Process electricity purchased	kgCO₂e.MWh^-1	340.8	0.1	1.4	Range reflects the carbon intensity of Swedish and UK electricity relative to EU 27
H₂SO₄^a		0.5	0.5	2	A range of -50% to +100% was considered sufficient
			to cover uncertainties in production emissions
NaOH^b		0.58
SO₂^a	kgCO₂		0.641
e.kg^-1
(NH4)2PO4^c		1.67
MgSO₄^.7 H₂O^d		0.56

^aBoustead database [38]. ^bDEAM database [39]. ^cEstimated from mass proportion of NH₃ with H₃PO₄ (reported in DEAM database). ^dReported in GREET 1.8, Ag_Inputs!AA43:AA52 – sum of production and process emissions, assumed to be the same as CaCO₃.