Consequential LCA - Part 2. Jannick H Schmidt. Barcelona 9 th November University, Denmark.

Transcription

1 Consequential LCA - Part 2 Jannick H Schmidt Barcelona 9 th November 2012 CEO, 2.-0 LCA consultants Associate Professor, PhD, Aalborg University, Denmark

2 What is modelling in LCA? Accounting: Just a matter of registration: What are the inputs and outputs of an activity => Easy!!! Modelling: When activities are linked, we go from accounting to modelling. => Not easy!!! Modelling introduces assumptions: Spatial: Which region/country is affected Time: Are historical, current or future technology/suppliers affected? Time: Is current capacity affected or is capital investments also affected? Supply and demand: If more than one supplier, which one is affected? By-products/waste: How to account for this? Which processes should be included? (Cut-off criteria) Modelling can be done in several ways: Consequential Attributional A1 B A2 2

3 Difference between alca and clca 1) clca versus alca linking 2) substitution versus allocation Multiple output activity Activity A Determining B Dependant B Market B Multiple output activity A Determining B Dependant 3

4 What is modelled in LCA? - The functional unit = a change in demand LCA = decision support (if not it is not an LCA) Purpose of clca: "what is the consequence of buying this product" "what is the consequence of choosing A in stead of B" "what is the consequence of implementing new technology" Purpose of alca: "how has this product been produced" "analyse the current situation" "historically tracking mass and energy flows" What information is relevant for decision maker? Irrelevant how products have been produced Relevant how the product will be produced if we change the demand (since future products are most often produced as existing, the existing technology is a good starting point) 4

5 What is modelled in LCA? - The functional unit = a change in demand Production volume / Capital Ngas Wind + biomass Coal t 0 Time 5

6 What is modelled in LCA? - The functional unit = a change in demand Production volume / Capital Ngas Wind + biomass Coal t 0 Time 6

7 Identification of affected suppliers in consequential modelling Identify affected suppliers: 4 steps a. Scale and time horizon b. Market delimitation c. Trends in the volume of the market d. Changes in supply and demand Weidema et al. (2009) Guidelines for applications of deepened and broadened LCA. CALCAS project, pp

8 a. Scale of the studied decision a. Scale and time horizon b. Market delimitation c. Trends in the volume of the market d. Changes in supply and demand The scale of the studied decision can be small or large Small scale is (unfortunately) the typical case Small => Default assumption Large scale is seen when introducing new technologies and regulations on significant markets, e.g. ban on palm oil Large => May affect the markets in which the change is taking place; nonlinear, requires special analysis 8

9 a. Time horizon of the decision a. Scale and time horizon b. Market delimitation c. Trends in the volume of the market d. Changes in supply and demand Relevant because background conditions may change over time, e.g. electricity, recycling rates, use of scarce materials Time horizon also concerns the distinction between short-term and longterm changes Short-term changes only affect current capacity utilisation Short-term: Not the typical case; relevant where no capital invenstments are planned/affected, e.g. in declining markets, monopolised or highly regulated markets Long-term changes affects capital investments Long-term: Default assumption 9

10 b. Market delimitation a. Scale and time horizon b. Market delimitation c. Trends in the volume of the market d. Changes in supply and demand Two cases: Decision affects specific supplier or market Specific supplier => this is the affected one (if it is not constrianed) Supply from market; Markets are typically differentiated: Geographically (natural geography, regulation, consumer culture) Temporally (peak hours, rush hours, season) In customer segments (obligatory properties: typically functionality, aesthetics, image) => Default: Assume no limits 10

11 c. Market trend (increasing/decreasing) Two cases: Market trend can be increasing/stable or decreasing Increasing/stable market => Default assumption: Typically modern and competitive suppliers are affected Decreasing market (decrease faster than replacement rate of capital equipment) => Least competitive suppliers are affected a. Scale and time horizon b. Market delimitation c. Trends in the volume of the market d. Changes in supply and demand 11

12 d. Changes in supply and demand a. Scale and time horizon b. Market delimitation c. Trends in the volume of the market d. Changes in supply and demand In LCA and IOA normal practise is to assume full elasticy of supply => demand for one unit leads to supply of one unit When suppliers are constrained or markets are imperfect (i.e. if producers can affect price), then => modify the assumption of full elasticity, see below Constrined suppliers: Regulatory constraints (max/min quotas, taxes, subsidies) Political constraints Availability of raw materials Waste treatment capacity Co-product constraints (determining co-product puts a constraint on the dependant co-products) Default => if no data, assume no constraints. Questionable constraints should be analysed in seperate scenarios 12

13 Identification of affected suppliers in consequential modelling Time aspects Market delimitation Market trend Short-term Long-term Specific Market Decreasing Increasing/constant Do not include capital goods Affected technology Specific technology Least competitive Most competitive Exclude constrained suppliers 13

14 Marginal suppliers & Practical recommendations - when is it important? Areas where significant differences on marginal/average are present: Electricity Aluminium Agricultural/food products (also depends on by-product utilisation) Material for treatment/by-products: waste, manure, scrap, straw 14

15 Modelling co-products in LCA 15

16 Why substitution? Substitution: 1. Follows ISO14040/44, ISO14067, ILCD Handbook 2. Modelling that reflects actual consequences (causality) 3. Effects of uncertainties and assumptions becomes transparent 4. Sometimes difficult to identify displaced product 5. Mass/substance balance is maintained Allocation: 1. Does not follow ISO14040/44, ISO14067, ILCD Handbook 2. Does not follow cause-effect relationships (impossible activities ) 3. Effects of uncertainties and assumptions are hidden in allocation factors 4. Difficult to use consistent allocation principle (only economic can be used) 5. Mass/substance balance is lost (against ISO14044, , last paragraph) Facts and myths: System expansion is impossible Uncertain unstable results 16

17 Allocation non-existing processes are created! Allocation Milk Meat Milk Meat 17

18 Unallocated milking cow (per 100 DM feed) 100 DM feed outputs = CH Manure 28.3 C in CO respiratory water 9.3 Milk 2.2 Meat 18

19 Allocated milking cow (economic allocation: milk 77%) 77 DM feed outputs = CH Manure 21.8 C in CO respiratory water 9.3 Milk 2.2 Meat Milk: 77% of economic turnover Meat: 23% of economic turnover 19

20 What is substitution? Product A = A+I-D 20

21 4 Conceptual cases 1) Combined production: output volumes of the co-products can be independently varied > Model (or allocate ) by physical causality Joint production: the relative output volume of the co-products is fixed 2) Used product is the determining co-product > Multiple-output activity + intermediate treatment - avoided activity 3) Used product is the dependant co-product > Exclude the multiple-output activity and include the marginal supply 4) Used product is the determining co-product & there are more than one determining co-products > Economical based system expansion and correction in use stage (most often: leads to same results as economical allocation) 21

22 Identifying the determining product(s) I Do the co-products have alternative production routes? When all co-products have an alternative production route, only one of these co-product is the determining one Products without alternative production routes are typically determining products 1. All co-products have alternative production routes Use relative, normalised market trend to identify the determining 2. Only one co-product with no alternative production route This is the determining product 3. More than one co-product with no alternative production route More than one determining product additional modelling 22

23 Identifying the determining product(s) II When all co-products have alternative production routes Only one of these co-product is the determining one 1) Provides an economic revenue that exceeds the marginal cost of changing the production volume the one with highest market trend 2) When only a combination fulfils condition 1) the one with lowest market trend in the combination normalised production volume B A time Alternative production costs: A: 100 B: 50 Marginal production costs: Fulfils 1)? < 50 Both B Only A A Only A+B A >150 None 23

24 Ex1: LCA of milk - Which one of the concenptual cases? Milk system Net calf Raising of calf Meat Dependant Milk Meat Determining Dependant 24

25 Ex1: LCA of milk -Conceptualcase 2 Process A: Milk system Product A: Milk Dependent co product Dependent co product Milk = A+I-D split-off point Processes I: Raising calf point of displacement Process D: Meat system Displaced product Process B, where the dependent coproduct is used Product B, in which the dependent coproduct is used 25

26 Milk allocation avoided milk Dairy cow newborn heifer newborn bull meat,live weight dead animal manure Raising heifer for milk production Raising newborn bull for meat production meat, live weight dead animal manure manure dead animal bull calf Raising bull calf for meat production meat, live weight dead animal manure Destruction fuel Manure treatment Utilisation of fuel Fertiliser Burning fuel nutrients energy Cattle meat 26

27 Milk allocation 27 Treatment Treatment Treatment Treatment Treatment Treatment EUR Milk EUR Nutrients EUR Energy EUR meat

28 Results: Denmark/Sweden ,0 2.0 kg CO2e per kg ECM 1, , ,5 0.5 LUC CF excl. LUC 0,0 0 DK SE DK SE DK SE DK SE DK SE DK SE DK SE DK SE ISO/CLCA Attributional IDF PAS

29 Ex2: LCA of minched bovine meat - Which one of the concenptual cases? Bovine meat system Tenderloin Minched meat 29

30 Ex2: LCA of tenderloin bovine meat - Concenptual case 4 > Prices are cleared by market > Demand for 1 DKK cause increase in production volume at 1 DKK > Thus demand for 1 kg tenderloin causes production of 8.4% of 1 kg = kg tenderloin > Total change in production volume: = kg tenderloin kg fillet kg other = kg > Demand for 1 kg tenderloin causes output from slaugterhouse at kg Emission per kg is 19 kg CO2e Emissions per kg is = 1.953*19 = 37 kg CO2e > Correction in use stage 1 kg tenderloin (only kg produced): Other users have to use less tenderloin and more fillet + other 30

31 iluc consequential and attributional versions Consequential model: A change in NPP 0 is modelled Average model: The total global NPP 0 (incl. land already in use) is modelled 31

32 Example of iluc using clca and alca (1 kg milk) 32

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