SEAD 520 Midterm

1. life cycle perspective
2. covers broad range of environmental issues
3. is quantitative (can be compared)
4. based on science (measurements, value judgements)

best estimate results
internationally standarized
comparison between products
best estimate for decisions

H2 -
avoids burden shifting

low probability events not well modelled
"hired guns" and misrepresentation of results in marketing
issues in consistency with system boundaries functional unit
assumptions often disputed

quantified performance of product
impact/functional unit

number of environmnetal releases (ghg) as a function of activty

number of resources used as a function of activity

1. description of methods
2. results
3. critical assesment or validation of results

1. define a product system
2. determine functions and functional unit
3. delineate system boundary
4. select inventory items and/or impacts studied

share of environmental burden belongs to product, describes environmental relevant flows to and from life clife
average data

how hlobal environmnetal burdens are affected by productionse of product, describes environmental relevant flows change in response to decisions
marginal data

intended application
reason fro study
intended audience
if results will be used in comparative analysis to the public

determine product system under investigation and how asseeement should take place
aim: ensure conissttentcy of methods, assumptions, data and reproducibility
9 items: 2-6 centeral as they influence decisions, 1, 7-9 is about reporting and communicating results

if full life-cycle is not being considered
in comparative studies it's okay to exclude identical processes
LCI model with ideal boundarries is basically impossible

apply to activities placed outside of scope of the model
3 criteria
1. mass
2. energy
3. environmental significance

foreground: process specific to object of study
background: process of a system not specific to object

class of environmnetal issues of concern to which LCA may be assigned area of protection

construction of a life cylce model, compilation of the relevant inputs and outputs, calculations of environemntal releases

0. identify unit processes
1. processes required for flow in the reference flow
2. processes required to deliver flow that perfrom a supporting function to the level 0 process
3. processes required to deliver services to the level 0 should be identified
4. processes required to produce and maintain infrastructure for level 0 process

primary, secondary, temporal, geospatial

functional: any flow of unit process that constitute its goal
non-functional: any flow that is not functions
multi-functional process: a unit process yielding more than 1 functional flow

1. it should be avoided (subdivid or expand product system)
2. should reflect the underlying physical relationship (mass or volume)
3. if not step 2, then other relationships, such as price

micro-level: small scale, will not cause structural chnages in adjacent systems
meso/macro-level: decision expected to cause change in adjacent systems
accounting: NOT for decision support --> purely descriptive/document, other interactions may be included

calculations of impacts from inputs, outputs, and emissions
1. classification
2. characterization

assesment of results relative to LCA purpose to make decision

describves environmental consequences by translating environmental loads from inventory analysis to impacts
considers effects (human, ecosystems, resources)
because it includes functional unit, it is different from environmental impact
last objective stage of LCA

class of environmnetal issues of concern to which LCI results may be assigned
catgeory indicator: quantifiable representation of an impact category

characterization model: mathematical model of the impact of elementary flows with respect to a category indicator
characterization factor: factor from characterization model which is applied to convert the LCI results to a commin unit of category indicator (GWP)

midpoint impacts: intermediate effects that do not demonstate full damages (eg increased radiative forcing)
damages: endpoint impacts or final part of chain

selection: determine impact categories, category indicators, and characterization models
classification: assignment of inventory results --> each to a catgory (eg CO2 to ghg, oil to energy)
characterization: calculation of category indicator results (reevent to endpoints and impacts)

normalization: calculation of magnitude of category indicator --> results from characterization are related to impact for each category
grouping: assignemnt of impact categories to group of similar impacrts (eg local, regional, global, high, med or low priority)
weighting: weights to different impacts, allowing intergration across all imacts allowing intergration across all impact categories

data quality check: analysis of the significance, uncertainty and sensitivity of LCIA results

often comprehensive boudnary is missing, category indicators are not equally precise/important, data/methods are incomplete, high levels of uncertainty

studying results in relation to goal and scope, sensitivity and uncertainty analysis, are boundary appropriate?
20% rule: need 20% difference between LCI results between 2 products

indentify significant issues
evaluate completeness
sensitivity and consistency (uncertainty assement)
conclusions
limitations
reccomendations

break-even analysis: where results break even
decision-maker analysis: who has power over each part of results?

contribution per quantity of elementary flow to a specific environmental impact
CF units: translate impact for elementary flow to a common unit

sum of characterization factors * elementary flows
for each impact category the indicator results are summed to determine overall results

broad environmental category which receives emission/impact --> air, soil, natural resources
sub-compartments make further distinctions

GWP uses the emissionsradiative forcing as an indicator
GTP is an instantaneous metric thta uses as an indicator the globa; average temperature increase of the atmosphere at a fture time that result for emissions
GTP is more concrete, reflects policy targets, although it is more uncertaint and more challenging to model

mid-point assesment model
from LCI data it predicts impact

calculates 18 mid-point indicators and 3 end point indicators
using diffirent cultural persoectives to make value weighting transparent
1. individualistic: short-term, impact are undisputed, tech optimisn with regard to human adaptation
2. hiearchist: scientific consensus about time-frame and plausibility of impacts
3. egalitirian: most precautious, longest time frame, all impact pathways for which data is available

ISO requires
reuslts and conclusions to be reported with 0 bias
transparancy
results and interpretations are used consistently with study goals

verifies if LCA met requirements for methods, data, interpretation, reporting and if it is consistent with principles
this enhances credibility and understanding
it is requried if comparative results are to be diffused to public

"general interdependcy" model: quantifies the inter-relationships among sectors of an economic system
direct and indirect economic inputs of purchases
can be extended to environmental and energy analysis
perception of what matters us vased on local factors

overestimares the dependence of the items
underestimates of supply chain effects

use EIO-LCA to frame LCA problems and set boundaries

OpenLCA is more modern
both have import/export posibilities, flexibility for importing processes, and flows
OpenLCA has empty database, SimaPro has built in choices

largest, most consistent LCI database
data on unit processes and system processes level
data on most industries

RoW: local scope that cover together the entire global production volume
market activities: bundles of inputs within geographical scope based on market shares

collection of choices made for database
differ in modeling choices
allocation and cut-off by allocation
APOS
consequential-long term

all intermediate flows are classes into "allocatable byproducts", "recyclable materials" or "waste"
ALCA
polluter pays- does not incentivize recycling
use of recycle materials = burden free

based on the premise that allocation of materials that require further treatment beofre they can be of immediate value is fundamentally challenging
performs an expansion of the allocation system to include all treatment processes for any by-products
ALCA
provides benefit to polluters for recycling

substitution is used to resolved multi-functionality instead of allocation
CLCA
credits for substitution

ecoinvent handles allocation in a specified way, databsed have been developed to reflect these specific decisions
uses primarily economic allocation

economic system that uses a systemic approach to mainatin a circular flow of resources, by recovering, retaining or adding to their value
least virgin resource use as possible

easiest approach
100% of virgin material production is allocated to the product using virgin material
boundary between life cylces where there is lowest market values (before waste collection)
incentivizes: use of recylced material when envrionemntal impact is less rgan virgin, recycling as alternate to waste treatment when the waste treatment has an impact
does no incentivize: when alternate waste treatment has environmental benefit

recommended when=
product contains recycled input , but littel is known about recycling after use
supply of recycled material is greater than demand or
the company doing the lCA has control over how much recycled material to use

if waste has negative economic value, boundary between life cylces is point where market value rises to 0 --> value - to + within unit process
envrionmental burdens for dismantaling are attributed to upstream and downstream
allocation is proprotional to total revenue

incentivizes: use of recylced materials, except when material recycling has significantly more impact than virgin material production
does not incentivize: material recycling after use when final disposal has a low impact
complex to apply because data on prices is needed

burden split equally
perspective that material use requires both virgin and final disposal that can no longer be recycled
environemntal benefits are equally attributed to products that are recycled after yse and products conatining recycled materials

incentivizes: use of recycled materials and recycling of products have use when there is environmental benefit

regionalized water scarcity footprint
goal: assess the extent to which other water users in the same area are at risk of water scarcity
CF between 1 and 100 ( 100 is low scarcity)

impacts at midpoint level
human toxicity potential
comparative toxic units
estimated increase in morbidity in total population/ unit mass of a contaminent emitted
assumes equal weighting beween cancer and non-cancer effects

fossil fuels, mineral ores, metal
functional use for society

can still be depleted
flow resources: can not be depleted (except localized cases) --> wind, solar, sometimes freshwater

CFCs are not degraded in troposphere, so over years they got to stratoshpere
in stratosphere CFCs break down into reactive chlorine radicals due to UV
CF: ODP

photochemical ozone depletion: secondary contaminents in troposphere caused by oxidation of primary contaminents
CF: POCP
need VOC or CO in the presence of NOx under light

epistenuc as a result of not perfectly capturing the characteristics of a product system

randomness inherent to the data or methods

important when comparing 2 product systems

2 rationals:
hotspot analysis - where are the highest and lowest LCI/LCIA results
comapring 2 product systems - which has higher impacts?

measurement uncertainty: when "ground-truthing"
geospatial: variations across world
paramater: inputs are uncertaint
temporal: changes in assumptions over time

process based = linearity, data quality
software tools: different softwares lead to different results
allocation: methods are not always consistent

accumulation of certain inputs, assumptions, methods, tools
potential remedies are only part of solution
uncertainty assesment is fundamental part of LCA

qualitative: interpretation via word description --> data quality assesment
semi-qualitative (heuristic) = rule of thumb, significance heuristics are pre-defined thresholds
qunatitative

sensitivity analysis:
varying inputs to test how analysis is affected by changes in assumptions
sometimes descriptive
tornado plots

ranges =
represets multiple estimates
can be reported with error bars, but usually in tables

distributions =
monte-carlo simulations

quantitative statement about the uncertainty associated with event under consideration
not a %
decision tree: tool for evaluating possible outcomes whenthe outcome of a decision is uncertain, and it is possible to estimate probabilities
ecoinvent pedigree matrix: has default uncertainty info, lognormal is most common