Using parameteriation to handle combined & joint co-production

Transcription

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2 Using parameteriation to handle combined & joint co-production Presentation the 48 th Swiss LCA Discussion Forum Zürich, Bo Weidema ecoinvent Centre slide 2

3 Content Combined and joint co-production Combined production: Modelling the physical relationships Joint production: Partitioning or substitution Parameters allocation: Revenue or physical properties Allocation at the point of substitution Substitution: Modelling market constraints slide 3

4 Combined and joint co-production Variable output proportions: Combined production subdivision according to physical relationships Fixed output proportions: Joint production substitution (system expansion), or partitioning (allocation) slide 4

5 Combined production: Modelling the physical relationships In v. 1 & 2: Individual allocation property each exchange, OR One dataset per product: Manual subdivision In v. 3: Mathematical relations from each exchange to the coproduct that causes the exchange: E = 2*A+3*B Automatic subdivision of dataset: E A = 2A and E B = 3B slide 5

6 Joint production: Partitioning or substitution slide 6

7 Parameters allocation: Revenue or physical properties Two rationales: Revenue as the driver the production ( economic causality ) Physical output as the driver the input Mutually exclusive: A choice has to be made One system model each allocation algorithm: Prerequisite: allocation property present in all intermediate outputs Revenue = Price * Amount True value = Revenue * True value relation (e.g. exergy) Mass = Dry mass * Amount (not LCA) Carbon = Mass * Carbon content (not LCA) slide 7

8 Parameters allocation: Revenue or physical properties Two rationales: Revenue as the driver the production ( economic causality ) Physical output as the driver the input Mutually exclusive: A choice has to be made The ecoinvent default allocation a compromise: True value as allocation property Allocation correction carbon: To ensure carbon balance slide 8

9 Allocation corrections (automatic) Multioutput Allocation correction carbon kg CO2 from air; 0.05 kg C Allocation correction carbon Multioutput, allocated X Multioutput, allocated Y

10 Parameters allocation: Revenue or physical properties Two rationales: Revenue as the driver the production ( economic causality ) Physical output as the driver the input Mutually exclusive: A choice has to be made The ecoinvent default allocation a compromise: True value as allocation property Allocation correction carbon: To ensure carbon balance Why only carbon? - Carbon is environmentally relevant both as input and output slide 10

11 Allocation - at the point of substitution: Coproducing C Material Treatment scenario (market) Material Final disposal () X Y Material Recycling () Material after recycling Z Final disposal () Recycling () - Material ( service) Treatment scenario (market) - Material ( service) Material after recycling Coproducing C X Y Z C : Coproducing C, with of wastes and by-products X Y Z slide 11

12 Allocation - at the point of substitution: Final disposal () Recycling () - Material ( service) Treatment scenario (market) - Material ( service) Material after recycling Coproducing C X Y Z C : Coproducing C, with of wastes and by-products X Y Z OR Final disposal () Recycling () - Material ( service) Treatment scenario (market) - Material ( service) Coproducing C Material after recycling X Y Z slide 12

13 Allocation - at the point of substitution: All activities are attributed to the activities that produce the materials that need, disregarding whether these are defined as wastes or by-products Allocation result unaffected by choices of the degree of detail (result cannot be manipulated by moving in or out) The full value of the by-products is attributed to the product system that gives rise to these by-products (any valuecorrection unnecessary) Price of the by-product is always available (while the price of a waste or by-product bee or during often can only be estimated, and if available may often be influenced by irrelevant properties of other wastes or regulatory conditions) slide 13

14 Substitution: Modelling market constraints By-product? From constrained technology? Modern? slide 14 Market B Technology constraints: I1 I2 I3 -B Singleoutput transming For Direct constrained link market: Affected B Conditional exchange consuming A Technology level as a machine-interpretable field: Outdated, Old, Current, Modern, New (classification) System model algorithm identifies which of the technologies are unconstrained, i.e. are available substitution in markets: in most cases Modern if available (depends on market trend)

15 slide 15 ecoinvent Centre, c/o Empa, Lerchenfeldstrasse 5, CH-9014 St-Gallen, Switzerland