Simplified time accounting for ILUC

Michael O’HareUniversity of California, Berkeley

July 2010

1EWG VII-10 O'Hare

Variables• Gv = “direct” – variable emissions from one MJ

production • Gc = ILUC – capital investment emissions for

one MJ production capacity

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Challenge

• combine Gv and Gc with minimal assumptions to generate a per-MJ GHG intensity

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Amortizing Gc into a variable cost •requires knowing production period•Ignores atmospheric persistence & cumulative warming•Should include a discount rate

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Kløverpris & Mueller: ILUC accelerates conversion

Implication of K-M model

A single year of biofuel production, if cropland is overall increasing for other reasons, displaces ILUC that would occur anyway to one year earlier.

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cvc

ccvc

ccvc

Gr

rG

GrGrG

Gr

GG

1

)1()1(

1

1

Note that:

• All discharges in this model occur within a year of each other, so residence time, analytic horizon, etc. don’t matter

• There is no avoiding a discount rate, for any action with a time delay component

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If ILUC is land clearing that will occur anyway next year, (annual land clearing > biofuel ILUC)

Example: US corn ethanol, Hertel et al Gc

Gtotal = 60 + (800 x .05/1.05)

= 98

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cvc G

r

rG

1

Refinements

• Production discharges might be discounted half a year (as though occurring in the middle of the year)

• Delayed afforestation needs to be handled with a complete time model

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