GATE 2023 ES – Question 46
Products P, Q have phases extraction, production, use, end-of-life. Each tuple is(CO₂ kg/tonne, CH₄ kg/tonne, tonnes/functional unit). P:(1,.75,4),(1.5,1,2),(.5,0,1),(1,.25,1). Q:(.75,.75,3),(.25,1,2.5),(0,.5,.75),(2,0,.75). With methane GWP23,select correct comparisons.
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Correct answer: (A) Extraction GHG:P>Q; (B) Production GHG:Q>P; (D) Total life-cycle GHG:P>Q
Explanation
For each phase, multiply mass by(CO₂+23CH₄). P emissions are73,49,.5,6.75 kgCO₂e/f.u.,total129.25. Q emissions are54,58.125,8.625,1.5,total122.25. Thus extraction P>Q, production Q>P, and total P>Q, but end-of-life Q<P. Select **A, B, D**.