potentials and limitations of lca in resource...

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International Workshop on Technospheric Mining

Vienna, 1-2 October, 2015

10.10.2015 Vienna 1

Potentials and Limitations of LCA in

Resource Management

Stefanie Hellweg


Resources may be dissipated

Resources may be depleted… „To Peak or not to peak?“

Renewables may be exhausted

Resource extraction and use have other impacts

10.10.2015 Stefanie Hellweg 2

Resources – what is the problem?


Tool for resource monitoring and management

Describes stocks and flows of resources

Helps to recognize resource scarcity and to identify recycling

potentials


Material flow analysis (MFA)

„How much of a resource is

available from primary and

secondary sources at which

point in time and who are the

users?“


Life Cycle Assessment (LCA)

Comparison of products or scenarios with regard to

environmental impact

10.10.2015 4


„Does my use of resources have

impacts on resource availability, the

environment and humans?“

„How can I use resources best to fulfill

my needs minimizing environmental

impact?“

Stefanie Hellweg


• Emissions (to

air, water and

soil)

• Resource

extraction

• Human

health

• Resource

depletion

• Ecosystem

quality

• Climate change

• Ozone depletion

• Photochemical

ozone formation

• Human toxic

effects

• Ecotoxic effects

• Eutrophication

• Acidification

• Land stress

• Water stress

• Resource

depletion

Environmental

interventions Damage

categories

Impact

categories

Are

as o

f Pro

tectio

n




Cumulative energy demand

Exergy (CExD, CEENE)

Emergy/SED

Statistical entropy

CML resource depletion

EDIP

Ore requirement indicator (ORI)

Eco-indicator 99 surplus energy concept

Recipe ore grade decrease and surplus cost concept

…


LCA: Existing resource indicators

Picture: Rørbech et al. ES&T 48, 2014


Correlation of impact scores quantified with vairous

resource indicators (> 2,500 ecoinvent processes)

• Most important energy resources: oil, gas, hard coal, uranium

• Metal resources: cadmium (in EDIP and EPS), copper, gold, indium

(ILCD), iron (SED), molybdenum (ORI), nickel and tantalum (EDIP)

• Minerals: gravel, sodium chloride

Rørbech et al, ES&T 48 (19), 11072–11081, 2014


Is resource use an economic and/or environmental

problem?

What is the safeguard subject?

What to assess? Scarcity? Resource quality?

Is there an „ultimate“ resource? … Energy? Exergy?

Money?

Integrate renewable and non-renewable resources?

Include damages of resource limitations?


Open questions

UNEP/SETAC Life Cycle Initiative working group


Depending on method, assessment in terms of

Scarcity of the respective resources (use-to-availability ratios)

Additional energy/cost needed for future resource extraction

Inherent resource property (e.g. exergy)

Considers also other environmental impacts of

processes attached with handling and use of

resources (climate change, toxicity etc.)


Resource Assessment in LCA


Assessment of resource depletion

Constraints rarely considered

Treatment capacity

Production capacity

Quality criteria

…

The influence of secondary resource quality on

environmental impacts is often not appropriately

taken into account

LCA lacks a systematic approach to identify optimal

solutions


Shortcomings of ‘classical’ LCA for waste and

resource management


Waste and resource management

?

Waste D Resource D

Resource C

Waste C

Waste B

Resource B

Waste A Resource A

Picture: C. Vadenbo 10.10.2015 Stefanie Hellweg 11


1. Depart from MFA of status quo

2. Define availabilities of resources and their potential uses

3. Define required functionalities of the system and system constraints

4. Run optimization algorithm and/or scenario analysis, minimizing

environmental impacts (and costs)

5. Output: set of material flows (if dynamically implemented also

stocks) that minimizes environmental impacts while satisfying the

defined needs


Approach – combine MFA and LCA

Stefanie Hellweg

P P

Picture: B. Steubing 12 10.10.2015


Case Study I: Sewage sludge management in Canton Zurich

10.10.2015 Stefanie Hellweg 13 Pictures: C. Vadenbo

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Case Study I: Results sewage sludge management in

Kanton Zurich (single-objective optimization)

Vadenbo C et al., Conservation and Recycling 89, 41-51, 2014

doi:10.1016/j.resconrec.2014.05.009

* BAU (Business as usual) reference case: 70% MSWI, 10% cement, 20 % Mono

*


Case Study I: Split between treatment options for sewage sludge

management in Kanton Zurich (single-objective optimization)

10.10.2015 Stefanie Hellweg 15 Vadenbo C et al., Conservation and Recycling 89, 41-51, 2014

BA

U

Min

cli

mate

ch

an

ge

Min

hu

man

toxic

ity

Min

eco

toxic

ity

Min

CE

xD

,

fossil e

nerg

y

Min

CE

xD

,

min

era

l

Min

ReC

iPe

H/A

, to

tal

MSWI 70% 30% 0% 0% 30% 0% 0%

Cement plant 10% 60% 60% 10% 60% 0% 60%

Mono

incineration 20% 10% 40% 90% 10% 100% 40%

MSWI 1 -4 50% 0% - - 0% - -

MSWI 5 50% 100% - - 100% - -

CP, sludge

dried at WWTP 100% 75% 75% 0% 75% - 75%

CP, dried at CP 0% 25% 25% 100% 25% - 25%

P-recovery no yes yes yes yes yes yes


Reference case not environmentally optimal

Optimal solutions mainly mix of treatment options

Consideration of capacities and quality constraints crucial!

Sludge co-processing in cement production maximized for

four out of six objectives

Leverage points for sludge mono-incineration

Energy and phosphorous recovery

Valorization of ash (residues) in cement production

Results sensitive to assumptions regarding displaced

product systems


Conclusions Case Study sewage sludge

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Case Study II: MSW in Switzerland

textiles

separate

collection

fibres

hazardous

waste

recovered

materials

EEE

separate

collection

export

(clothes)

PET

separate

collection

PET

recycling

recyclate

(low quality)

recyclate

(1st quality)

paper

separate

collection

paper

recycling

paper fibres

rest batteries

mercury

export (PET)

biogenic

products

separate

collection

anaerobic

digestioncomposting

biogas

digestate

compostferro-

manganeseferrous scrap

zinc

collection (Al

& tinplate)

bottles for

washing

tinplate

separation

tinplate

recycling

cullets for

foam glass

glass bottle

collection

glass

separate

collection

mixed color

collection

separate

collection

aluminium

(Al)

flue gas

treatment

sorting

glass

recycling

MSWI

air cleaning

residues

scrap metals

bottom ash

treatment

export

(cullets)

glass cullets

for recycling

export

(aluminium)

single color

collectionbatteries

WEEE

treatment

battery

recycling

separate

collection

export

(paper)

household consumption

0

MFA LCA Optimization

v

PhD project Melanie Haupt 10.10.2015 Stefanie Hellweg


Influence of resource quality on environmental

impacts of recycling

Substitution

International disposal chains

Unknown pathways

Data availability

….


Challenges

PhD project Melanie Haupt

MSWI

EAF


Pour scrap quality influences environmental impacts of the

recycling process and introduces pollutants in secondary

products.

Model can in principle capture these effects (also pollutant

accumulations), but data gaps on influence of resource

quality are large.

Selected conclusions for MSW case study



LCA can appropriately assess (most) environmental

impacts of resource use, but there is a controversy on

whether and how resource depletion as such shall be

assessed

The combination of MFA, LCA and optimization

Allows for comprehensive optimization of resource/waste

management systems

Reveals trade-offs

Can be used to derive regional resource strategies


Conclusions


The assessment of resource depletion is discussed in an

ongoing working group of the UNEP/SETAC Life Cycle

Initiative.

MFA-LCA model needs further development concerning

Modeling of substitution

Temporal dynamics

Uncertainty modeling

Applications are being extended

Optimization of biomass use in Denmark (IRMAR)

Wood management

Optimization of energy supply of cities

…


Outlook


[email protected]


Thank you!

Funding is gratefully acknowledged from:

• Swiss National Science Foundation (NRP 67 and 70)

• Cantonal office of waste, water, energy and air (Zurich)

• Development centre for sustainable management of recyclable waste and resources (ZAR)

• Danish Council for Strategic Research (grant no. 11-116775; the IRMAR project)

• Holcim

• Federal Office of Environment

• Federal Office of Energy

ESD group, in particular

Melanie Haupt,

Thomas Sonderegger,

Bernhard Steubing,

Carl Vadenbo

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