crash course consequential lca and modelling with …...2019/04/24 · lorie hamelin, phd senior...

Lorie Hamelin, PhDSenior researcher

PI on Make Our Planet Great Again Project Cambioscop

Crash course – Consequential LCA and

modelling with SimaPro

@[email protected]

24th.April.2019. Toulouse, LCA lab of INP-ENSIACET

mailto:[email protected]

LISBP • Laboratoire d’Ingénierie des Systèmes Biologiques et des Procédés •

Agenda

Morning – 9.00 to 12.00

• Presenting each other & opening computers

• Introductory case

• LCA in a nutshell

• Phases of an LCA

• Consequential (and attributional) LCA

Afternoon – 13.30 to 18.30

• Exploring SimaPro

• Coffee cup exercise


Presentations


Don’t be afraid to ask questions … and to participate, it’s

interactive!


Maabjerg Energy Centre

2G Bioeth300,000 t straw

77 M liters bioethanol

92,000 t molasses

92,000 t solid biofuel


LCA in a nutshell


What is LCA?


What is LCA?

•A leading environmental assessment methodology

•A standardized methodology of the ISO 14040

series

•ISO 14040: 2006 Environmental management – Life cycle

assessment – Principles and framework

•ISO 14044: 2006 Environmental management – Life cycle

assessment - Requirements and guidelines

•Cradle-to-grave

•LCA assesses quantitatively the environmental

consequences of products/services considering their

whole life cycle


What is LCA?

Materials production

Product manufacture

Use and maintenance

Disposal

.

.

.

.

.

.


What is LCA?

•Now that you know about the whole flow of substances of

your product…how can you judge of the environmental

consequences?


What is LCA?

•Now that you know about the whole flow of substances of

your product…how can you judge of the environmental

consequences?

•Impact assessment (one of the 4 phases of an LCA) will allow you to

translate these flows of substances into environmental impacts

12

• Impact assessment :

Fictive example: For providing a luminous flux of 1 lumen during 1 hr in a

5m2 room

0%

20%

40%

60%

80%

100%

Global

warming 100 y

(kg CO2 eq.)

Acidification

(g SO2 eq.)

Eutrophication

(g PO4)

Total energy

End-of-life Use

Distribution Production

kg CO2 eq.

Ref: Above (fictive). Right: Tichelen et al. (2006)

What is LCA?

What is LCA? – (III)

13

Ref: Hamelin et al. 2014. Applied Energy 114

Ref: EC (2019). doi:10.2777/251887


What is LCA?

•Now you have quantified the environmental impacts

involved in providing a luminous flux of 1 lumen during 1 h

(to light a given room) with a given bulb…yes…but…


What is LCA?

•Typically, an LCA answers 2 main questions:

•Is A better than B?

•Where (in the life cycle) are the hot spots?

•Application covers various perspectives:

•Ex1: What choices to make for the energy system (e.g. biofuels)? (government perspective)

•Ex2: What to do with my empty mayonnaise (plastic) bottle? // Single use or re-usable diapers? (citizen perspective)

•Ex4: How can my product be more efficient on an environmental perspective? (industry perspective – product development)


What is LCA?

•Other VERY important questions:

•What does it replace?

•What are the consequences?

•More of “A” is produced (and what does that involve?)


What is LCA?

•In 3 bullets:

•Focus on services (different ways to provide a given service to

society)

•Comparative

•Holistic


What is LCA?

•LOST IN THE TERMS?

•Cradle-to-gate

•Cradle-to-cradle

•Well-to-wheel

•Carbon footprint

•System analysis

•Product Environmental Footprint (PEF)

•Environmental Product Declaration (EPD)


Phases of an LCA


Phases of an LCA

Goal and scope

definition

Inventory analysis

Impact assessment

Interpretation Application

ISO 14040 (2006)

•Development and/or

improvement of products

•Laws, public policies

•Marketing

•Etc…


Phases of an LCA

•LCA is an iterative process ….you need the result in order

to scope it!

Source: Hauschild M (2009). Introduction to Life Cycle Assessment. Ease Waste PhD course, 11.06.2009, DTU.


Goal and scope

•Goal definition:

•Which decision(s) is this LCA intended to support?

•What is the target audience to whom the results will be

communicated?

•What are the reasons to carry out this LCA?


Goal and scope

•Scope definition covers (among others): •The object of the study (product/system, market segment, alternatives)

•Definition of primary and secondary services

•Definition of a functional unit (Quality, Quantity, Duration)

•Defining a reference flow

•Delimitation of the scope

•Geographically, temporally and technologically

•System equivalency (process flow diagram)

Defined in ISO 14040

***Scope definition is probably the most important phase of the LCA***


Goal and scope

•Reference flow (examples - i)

FU: Absorb and contain urine & faeces of a baby (age 0 – 12 month ) for 1 year

A: Single use diaper B: Cotton diaper

(38 diapers/week) (68 diapers/week)

(150 use/diaper)

(individual hand washing

between each uses)

*DIAPERS*


Goal and scope

•Reference flow (examples - i)

FU: Absorb and contain urine & faeces of a baby (age 0 – 12 month ) for 1 year

A: Single use diaper B: Cotton diaper

(38 diapers/week) (68 diapers/week)

(150 use/diaper)

(individual hand washing

between each uses)

*DIAPERS*

1976 (single use) diapers 23.6 (cotton) diapers

3536 washings


Goal and scope

•Reference flow (examples - ii)

A: Long duration paint B: Short duration paint

(0.3 kg/m2)

(duration of 20 years)(0.3 kg/m2)

(duration of 10 years)

*PAINTS*


Goal and scope

•Reference flow (examples - ii)

A: Long duration paint B: Short duration paint

(0.3 kg/m2)

(duration of 20 years)(0.3 kg/m2)

(duration of 10 years)

*PAINTS*

30 kg of paint A 60 kg of paint B

FU: Providing 100 m2 of painted wall with an opacity of 98%, for 20 years


Goal and scope

•Reference flow (examples - iii)

FU: Providing 200 ml of hot beverage 3 times/d for 365 days.

A: Plastic 1-use cup B: Ceramic mug

*Hot beverage containers at a workplace*


Goal and scope

•Reference flow (examples - iii)

FU: Providing 200 ml of hot beverage 3 times/d for 365 days.

A: Plastic 1-use cup B: Ceramic mug

*Hot beverage containers at a workplace*

(usable once per use, assuming there

is always only 1 cup/per use, e.g. not

doubled for avoiding fingers

burning.)

(usable for 4380 uses)

(washing after each use)

1095 units 0.25 unit1095 washings


Goal and scope

•Drawing your process flow diagram:

services

Eg.: xx km of

transport demand

nature.process

Flow

Eg.: xx GJ diesel;

(X GJ/km)Eg.: refining

Flow

Eg.: XX GJ oilEg.: oil

extraction

•Use dotted lines for avoided processes / flows.

•Draw the process flow diagram for your reference and for each alternative to be

assessed

processFlow Flow process


Consequential and Attributional LCA


A pfd in 7 minutes

•In team : Bio-diesel from animal fat example

•FU: 10 km of transportation in a “conventional” 5-seat

passenger car in Europe (EU-4 engine)

•For this, you will need to produce A MJ bio-diesel:

•Inputs for esterification process:

• Pig fat: B MJ

• Others inputs (methanol and energy) can be considered as “others”

•Co-products:

• Co-product 1: C MJ glycerin. Can be used for heat

• Co-product 2: E MJ distillation residues. Can be used for heat.

• Co-product 3: G kg catalyst residue. Rich in potassium, can be used in agriculture.


Introduction to consequential thinking

•Bio-diesel from animal fat example:

•How much of the fertilizer shall be attributed to the animal fat?

•Would we produce more pigs because we want more

biodiesel?

•But…what do we do today with the animal fat???


In consequential LCA, it would be modelled like this

Esterification

biodieselProviding XX km

transportation

Glycerine

&

distillation

residues

Pig fat

Used in boiler heat

Marginal

mineral K

fertilizerFat used in

boiler

heat

Marginal heat

production

Catalyst

residues

Applied on

arable landK

Marginal heat


In attributional LCA, it may be modelled like this…

Farming

pigs

Dead pigs (and

their

management)

Manure (and its

management)Esterification

biodiesel

glycerine

Catalyst

residue

Distillation

residue

Meat

processing

meat

Blood & meal

fat


Consequential LCA

•What are the consequences of implementing system A instead of system B?

=> More of “A” is produced (and what does that involve?)

System

Alternatives

LCA

Conclusion

Decision

Difference/consequence

Ref: Wenzel et al. (2009)


Consequential LCA

•Simple representation of LCA


Product manufacture

Use and maintenance

Disposal

.

.

.

.

.

.



Consequential LCA

•Systems are a little more complex…


Product manufacture

Use and maintenance

Disposal

.

.

.

.

Disposal Materials production

Preceding system(s) Proceeding system(s)

Adjoining system(s)

SS1 SS2 SS3 SS4 SS5

PS

SS6 .

. . . .

.

SS*



Consequential LCA

•And even more complex…(several suppliers, but only the “marginals” react to a demand change



Consequential LCA

• What is the environmental difference between this

product ‘being there’ and ‘not being there’, i.e. what is

the environmental consequence of

demanding/supplying more or less of this product?

• The formula of consequential LCA:

2B/-2B = ?


Consequential LCA, in a nutshell

• 1) System expansion to handle multi-functionality

•Tracking the consequences of the demand change

• Identifying which products are replaced on the market by arising co-

products. If constrained, what service is replaced?

•System boundary: the system boundary is expanded in order to

include (only) what is affected by a change in the use of the product

for which the LCA is made.

•When to stop? At the point where consequences become so small,

or uncertainty so large, that further expansion of the boundary will

yield no significant information for the decision to support.

•2 key expansion cases: consider co-products + consider constrained

resources


Consequential LCA, in a nutshell

•2) Consequential LCA uses data from MARGINAL

supply only

•Which technologies/suppliers will respond to a change in

demand???

•Marginal supply: The response to a marginal change in demand on

the market in question

•Remember: a process is part of the system if it can respond to a

change in demand for your studied product/service


Consequential LCA

Rape production

Rape processing

Rapeseed oil

Rape straw

EsterificationBio-diesel

Driving

Arable land

OilRefining

Diesel

Petrol

Other

Rapeseed cake Glycerine

•Example: 1st generation biodiesel from rape


Consequential LCA

Rape production

Rape processing

Rape seed oil

Rape straw


Driving

Arable land

OilRefining

DieselPetrol

Other

Rapeseed cake Glycerine

Displaced service by the use of rape straw

Displaced service by the use of rapeseed cake

Food/feed

Arable land

Marginal supply for displaced service


Displaced service by the use of glycerine


•Example: 1st generation biodiesel


Consequential LCA


Rape production

Rape processing

Rape seed oil

Rape straw


Driving

Arable land

OilRefining

DieselPetrol

Other

Rapeseed cakeGlycerine

Animal fodder (protein)

(based on a published LCA: Jensen et al., 2007)


Consequential LCA


Rape production

Rape processing

Rape seed oil

Rape straw


Driving

Arable land

OilRefining

DieselPetrol

Other




Arable landSoybean production Soy meal

Soy oil


Consequential LCA


Rape production

Rape processing

Rape seed oil

Rape straw


Driving

Arable land

OilRefining

DieselPetrol

Other





Soy oil

Palm fruit productionArable land

Palm meal

Palm oil


Consequential LCA


Rape production

Rape processing

Rape seed oil

Rape straw


Driving

Arable land

OilRefining

DieselPetrol

Other





Soy oil

Palm fruit productionArable land

Palm meal

Palm oil

Arable landBarley production

Barley Animal fodder (carbohydrate)


Additional readings on consequential LCA

• Available as a pdf package upon request!


Phases of an LCA -II


Inventory analysis

Goal and scope

definition

Inventory analysis

Impact assessment


ISO 14040 (2006)




•Marketing

•Etc…


Inventory analysis


Inventory analysis

•Foreground data (your system, i.e. processes of your pfd)

•Direct contact with the industries, manufacturing datasheets

•Lab or pilot-scale measurements

•Scientific studies (scientific journals, reports, etc,)

•Estimation methodologies

•Background data

•Primarily from databases (like Ecoinvent)

Let’s relate it to the examples used so far


Inventory analysis

•Useful tools for data searching•Direct communication (phone, email)

•Eurostat / FAO / IFA, etc.

•Our World in data / Index Mundi

•SimaPro listserv: http://lists.pre-sustainability.com/scripts/wa-PRECBV.exe?SUBED1=LCALIST

•PEF Pilot phase: http://ec.europa.eu/environment/eussd/smgp/PEFCR_OEFSR_en.htm

•IPCC Assessment reports and National Guidelines for GHG

•Life Cycle Initiative: https://www.lifecycleinitiative.org/

•JRC Data Catalogue and Bioeconomy Knowledge Centre:

http://data.jrc.ec.europa.eu/dataset?sort=sort_criteria+desc%2C+title_string+asc

https://biobs.jrc.ec.europa.eu/

•EPLCA: http://eplca.jrc.ec.europa.eu/

•Databases for scientific articles: Web of Knowledge, Science Direct, etc…

http://lists.pre-sustainability.com/scripts/wa-PRECBV.exe?SUBED1=LCALIST

http://ec.europa.eu/environment/eussd/smgp/PEFCR_OEFSR_en.htm

https://www.lifecycleinitiative.org/

http://data.jrc.ec.europa.eu/dataset?sort=sort_criteria+desc,+title_string+asc

https://biobs.jrc.ec.europa.eu/

http://eplca.jrc.ec.europa.eu/


Inventory analysis

•Ecoinvent is recognized as the world's leading supplier of consistent and transparent life cycle inventory data

•The database contains more than 3500 industrial processes, and these are extensively documented

•Data are available for the following sectors: Energy, transport, building materials, chemicals, washing agents, paper & board, agriculture and waste management.

•The database is described at www.ecoinvent.ch

http://www.ecoinvent.ch/


Inventory analysis

• Other LCI databases for background data

Ref: Hamelin et al. (2010)

651.9 kg liquid

fraction ex-

separation per FU

Reference pig

slurry (scenario A)

Liquid fraction (fattening pig

slurry) (scenario F)

Comments

Input

Liquid fraction “ex separation”

1000 kg The emissions are calculated relative to this.

Slurry “ex housing” 1000 kg Water 86 kg 86 kg

Concrete slurry store Included Included As in scenario A.

Cut straw 2.5 kg 2.5 kg As straw is regarded as a waste product from cereal production (rather than a co-product), the life cycle data of straw production are not included.

Output

Slurry “ex storage” 1086 kg 1086 kg

Energy consumption Electricity 1.45 kWh Electricity for pumping and stirring (see text).

Emissions to air

Carbon dioxide (CO2) 0.18 kg (if calculated as in Annex F

:2.75 kg)

0.396 kg Calculated from CH4 emissions: kg CO2 = kg CH4 * 1.42 (see text).

Methane (CH4) 1.94 kg 0.279 kg Based on IPCC methodology (IPCC, 2006), but with VS of separated liquid fraction, see text.

Ammonia (NH3-N) 0.11 kg 0.0825 kg NH3-N = 2% of the total N in the liquid fraction “ex-separation”, see text.

Direct emissions of Nitrous oxide (N2O-N)

0.033 kg 0.0249 kg

Evaluated based on reference slurry emissions, adjusted with relative total N ratios (see text).

Indirect emissions of Nitrous oxide (N2O-N)

0.0014 kg 0.00107 kg

0.01 kg N2O–N per kg (NH3–N + NOX–N) volatilised (IPCC, 2006, table 11.3), see text.

Nitrogen monoxide (NO-N) (representing total NOX)

0.033 kg 0.0249 kg

Estimate based on Dämmgen and Hutchings (2008), consisting of assuming that NO-N = (direct) N2O-N * 1, see text.

Nitrogen dioxide (NO2-N)

No data No data No data

Nitrogen (N2-N) 0.099 kg 0.0747 kg

Estimate based on Dämmgen and Hutchings (2008), consisting of assuming that N2-N = (direct) N2O-N * 3

Discharges to soil and water

None None Assumed to be none, as leakages from slurry tanks are prohibited in Denmark

Inventory analysis (V)

60

For processes where composition is important, don’t forget your mass balances!

(example from Hamelin et al., 2010)


Inventory analysis

•ISO standard for LCA presents some requirements regarding inventory analysis. The main principles to remember:

•All that has significance should be included

•All data shall be documented, as well as their uncertainties

•Treatment of missing data should be documented

•Cut-off criteria: a process may be exclude if it contributes to less than X% of the environmental impacts (considered in the study)


Inventory analysis

•Sensitivity analysis:

•There may be some assumptions/calculations methods/data etc… that you used but that are rather uncertain

•The sensitivity analysis allows you to assess how sensitive the final results are to these choices

•Basically, it consists to perform the LCA again by changing the potentially sensitive parameter by another, and evaluate how this affects the results


Inventory analysis

•MonteCarlo:

A<B B Ryegrass Willow Miscanthus

A AD GA CO CF AD GA CO CF AD GA CO CF

Ry

eg

rass AD x

GA 60 x

CO 100 66 x

CF 100 81 59 x

Willo

w

AD 98 x

GA 90 100 x

CO 86 100 77 x

CF 97 100 78 61 x

Mis

ca

nth

us

AD 90 82 x

GA 60 45 100 x

CO 86 43 100 68 x

CF 83 48 100 80 67 x

Table S18. Uncertainty analysis for global warming based on MonteCarlo analysis: the values indicate the number of occurrences

(%) in which the bioenergy scenario ‘A’ resulted in less environmental impacts than ‘B’ (e.g., 100 means that ‘A’ resulted in less

impacts than ‘B’ in 100% of the occurrences).

Ref. Tonini et al. (2012)


Impact Assessment

Goal and scope

definition

Inventory analysis

Impact assessment


ISO 14040 (2006)




•Marketing

•Etc…


Impact assessment

•Why impact assessment?

Substance Compartment Unit Alternative A* Alternative B*

Ammonia Air kg 3.0 1.7

Carbon dioxide Air kg 110.8 114.0

Carbon monoxide Air g 154.1 66.4

Dinitrogen monoxide Air g 53.1 83.1

Methane Air kg 4.0 4.6

Nitrogen oxides Air g 328.1 320.0

NMVOC Air g 3.9 2.6

Nitrate Water g 198.0 0.9

Phosphate Water g 12.3 264.1

Copper Soil g 30.1 2.7

Zinc Soil g 48.6 10.0

* Fictive example


Impact assessment

•Mains steps of an impact assessment

•Classification: Assignment of emissions to impact categories according to their potential effect

•What does this emission contribute to?

•Characterization: Quantification of contributions to the different impact categories

•How much could it contribute?

•Normalization: Expression of the impact potentials relative to a reference situation

•Comparing apples with apples

•Valuation: Ranking, grouping, or assignment of weights to the different impact potentials


Impact assessment

• Impact categories?


Impact Assessment

• Classification game


Impact assessment

•The overall concept

Inventory

CH4

CO2

N2O

NH3

NOx

N, water

P, water

SO2

Cu, soil

(…)

Impacts (chosen)

Global warming

Acidification

Ozone formation

Eutrophication (N)

Eutrophication (P)

(…)(…)

Characterisation

kg CO2 eq.

kg SO2 eq.

kg C2H4 eq.

kg N

kg P

(…)


Impact assessment

• PEF


Impact assessment

•See also latest recommendations for some categories in:


Impact assessment

Characterization

•Quantification of the contribution from each substance to the impact category

•Each impact category has a reference substance; all other contributions to the

impact category are calculated relative to it by equivalence factors

•The reference substance and equivalence factors will depend of the impact

assessment method you use.

• Most methods, reference substances and equivalence factors are

available in SimaPro.

•Description of most methods available in Ecoinvent report number 3.


Impact assessment

•Should we treat the sludge (B) or not (A) ? (fictive

example)

Impact

categories

Option A Option B Unit

Global

warming

174.0 461.1 kg CO2 eq.

Acidification 868 2.48 kg SO2 eq.

Photochemical

ozone

formation

200 720 kg C2H4 eq.

Nutrient

enrichment

3.576 5.364 kg NO3- eq.


Impact assessment

Normalization

•Normalized result = Characterized result / Reference value

•A way to handle trade-offs so we can compare all impact categories with the

same unit (comparing apple with apple)

•Unit: The person equivalent

•The impact from an average person

•In a given reference year

•Yearly total emission (global/regional/local) per person

(worldwide/regional/local)

•It provides a relative impression of the environmental impact caused by your

system compared to the impact from one average person


Impact assessment

•The overall concept (2)

Characterisation

kg CO2 eq.

kg SO2 eq.

kg CFC-11 eq.

kg N

kg P

(…)

How much of

these are emitted

per world citizen or

European citizen?

(for a given

reference year)

Ex.: 8.7 t CO2

eq. / pers*y

GW

Aci.

O.D.

Eu-N

Eu-P

Person eq. (yr 1994)





Normalisation Valuation

Ranking,

grouping or

assignment of

weights to the

different

impact

potentials.


Impact assessment

Ref.: Adapted from results of Brentrup et al., 2001

0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

0.16

0.18

0.2

CAN UAN Urea

PE

* y

ear

Eutrophication

Acidification

Global warming

• Example of normalized results


SimaPro


Just purchased SimaPro?

• Install it with your registration ID and code via (and

of course read the installation instruction manual):

https://support.simapro.com/articles/Article/SimaPro

-Installation/

• Find the database (typically under:

C:\Users\Public\Documents\SimaPro)

• Good practice (and advice): Copy the (virgin)

database and never touch it, so you always have an

original protected copy on your hard drive

Always do this

even if you work

on a network!

https://support.simapro.com/articles/Article/SimaPro-Installation/


How it looks like the 1st time you open SimaPro


SimaPro

• Remember: SimaPro is just a software – you can

thus NOT say that your data comes from SimaPro

(it comes from one of the database available in

SimaPro)


SimaPro

• Exploration + coffee cup exercise


Key references mentioned

• EC (2019): Environmental impact assessments of innovative bio-based product. https://publications.europa.eu/en/publication-detail/-/publication/15bb40e3-3979-11e9-8d04-01aa75ed71a1

• Tonini et al. 2012: Bioenergy production from perennial energy crops: a consequential LCA of 12 bioenergy scenarios including land use changes. https://pubs.acs.org/doi/abs/10.1021/es3024435

• Hamelin et al. 2010. LCA of biogas from separated slurry. https://www2.mst.dk/udgiv/publications/2010/978-87-92668-03-5/pdf/978-87-92668-04-2.pdf

(also published as a paper in ES&T here: https://pubs.acs.org/doi/abs/10.1021/es200273j )

• Jensen, K. H., Thyø, K. A., Wenzel, H., 2007. Life Cycle Assessment of Bio-diesel from Animal Fat. Institute for Product Development, Technical University of Denmark, Kgs. Lyngby, Denmark

• Hamelin et al. 2014. Environmental consequences of different carbon alternatives for increased manure-based biogas. https://www.sciencedirect.com/science/article/pii/S0306261913007800

About the PEF (also called EF only when referred to in terms of methodology)• http://ec.europa.eu/environment/eussd/smgp/PEFCR_OEFSR_en.htm (see technical reports)

• http://ec.europa.eu/environment/eussd/smgp/pdf/PEFCR_guidance_v6.3.pdf (see list of recommended models, table 2, among others)

• https://www.pre-sustainability.com/sustainability-consulting/sustainable-innovation/product-environmental-footprinting

• Critic on the PEF weighting methodology: https://lca-net.com/blog/pef-weighed-and-found-wanting/

Mentioned during the lecture (/Gabriella): • Weidema BP (2017). Estimation of the size of error introduced into consequential models by using attributional background

datasets. https://link.springer.com/article/10.1007/s11367-016-1239-x

More on consequential LCA:• https://consequential-lca.org/

• See pdfs sent jointly with this power point (Wenzel et al. 2009 and Brandao et al. 2017)

• PhD dissertation by L. Hamelin (along with appendix): https://www.ceesa.plan.aau.dk/publications/phd-dissertations/

https://publications.europa.eu/en/publication-detail/-/publication/15bb40e3-3979-11e9-8d04-01aa75ed71a1

https://pubs.acs.org/doi/abs/10.1021/es3024435

https://www2.mst.dk/udgiv/publications/2010/978-87-92668-03-5/pdf/978-87-92668-04-2.pdf

https://pubs.acs.org/doi/abs/10.1021/es200273j

https://www.sciencedirect.com/science/article/pii/S0306261913007800

http://ec.europa.eu/environment/eussd/smgp/PEFCR_OEFSR_en.htm

http://ec.europa.eu/environment/eussd/smgp/pdf/PEFCR_guidance_v6.3.pdf

https://www.pre-sustainability.com/sustainability-consulting/sustainable-innovation/product-environmental-footprinting

https://lca-net.com/blog/pef-weighed-and-found-wanting/

https://link.springer.com/article/10.1007/s11367-016-1239-x

https://consequential-lca.org/

https://www.ceesa.plan.aau.dk/publications/phd-dissertations/