Life Cycle Assessment (LCA)

Life Cycle Assessment (LCA) Life Cycle Assessment is an environmental management tool. The International Organisation for Standardisation (ISO) defines LCA as A compilation and evaluation of the inputs, outputs and potential environmental impacts of a product throughout its lifecycle

Life Cycle Assessment (LCA) LCA considers the following stages in the life cycle of an activity Extraction and processing of raw materials Manufacturing Transportation and distribution Use, reuse and maintenance Recycling Final disposal

Life Cycle Assessment (LCA) Primary Resources Emissions & Waste Extraction & Processing Production Use Reuse/Recycle Disposal

Life Cycle Assessment (LCA) The LCA methodology is standardised by a series of ISO standards and includes the following phases 1. Goal and scope definition (ISO 14041) 2. Inventory Analysis (ISO 14041) 3. Impact Assessment (ISO 14042) 4. Interpretation (ISO 14043)

Goal and Scope Definition The first phase of LCA includes definition of The purpose of the study and its intended use The system and system boundaries The functional unit Data quality, the assumptions and limitations of the study

Goal and Scope Definition In full LCA studies, the system boundary is drawn to encompass all stages in the life cycle from extraction of raw materials to the final disposal. However, in some cases, the scope of the study will demand a different approach, where it is not appropriate to include all stages in the life cycle. This is usually the case with commodities, for instance, which can have a number of different uses so that it is not possible to follow their numerous life cycles after the production phase. The scope of such studies is from “cradle to gate”.

Goal and Scope Definition One of the most important elements of an LCA study is a functional unit. The functional unit represents a quantitative measure of the output of products or services which the system delivers. In comparative LCA studies, it is crucial that the systems are compared on the basis of equivalent function, that is functional unit Eg comparison of different beverage packaging should be based on their equivalent function which is to contain a certain amount of beverage. The functional unit is then defined as “the quantity of packaging necessary to contain the specified volume of beverage”.

Inventory Analysis The purpose of the “Inventory Analysis” is to identify and quantify the environmental burdens in the life cycle of the activity under study. The burdens are defined by material and energy used in the system and emissions to air, liquid effluents and solid wastes discharged into the environment. Inventory Analysis includes the following steps Detailed definition of the system under study Data collection Allocation of environmental burdens in multiple-function systems Quantification of the burdens

Life Cycle Inventory Analysis Materials Acquisition Formulation, processing and Manufacturing Product Distribution Product use Recycle, products, components, materials Waste Management Inputs Materials Energy Water Air Outputs Principal Products Coproducts Water effluents Airborne emissions Solid Waste Other Environmental interactions

Life Cycle Inventory Analysis Environment System Functional Outputs Inputs Emissions/Wastes Subsystems

Life Cycle Inventory Analysis Environmental burdens are then quantified for each subsystem according to the formula Where bcj,i is burden j from activity i and xi is a mass or energy flow associated with that activity

Calculating Environmental Burdens & Impacts in LCA - Example The system in this example has one functional output and each activity i from extraction of raw materials to final disposal generates a certain amount of CO2 and CH4. Extraction Production Use Disposal CO2 = 0.2 kg/t CH4 = 0.1 kg/t x1 = 2t/tFU CO2 = 0.3 kg/t x2 = 1.5t/tFU CO2 = 0.1kg/t CH4 = 0.1kg/t x3 = 1t/tFU CH4 = 0.3kg/t x4 = 0.5 t/tFU x1 x2 x3 x4 FU

Calculating Environmental Burdens & Impacts in LCA - Example Using the Environmental Burdens equation the total environmental burdens per functional unit related to the emissions of CO2 and CH4 are therefore BCO2 = ∑bcCO2 . xi = (0.2)2+(0.3)1.5+(0.1)1+(0.1)0.5 →BCO2 = 1.0 kg/tFU BCH4 = ∑bcCH4 . xi = (0.1)2+(0.1)1.5+(0.1)1+(0.3)0.5 →BCH4 = 0.6 kg/tFU

Classification Factors for Selected Burdens

Calculating Environmental Burdens & Impacts in LCA - Example EGWP = (ecCO2)BCO2 + (ecCH4)BCH2 = 1(1) + 21(0.6) → EGWP = 13.6 kg CO2 equiv / tFU

Impact Assessment The impacts most commonly considered in LCA are Non-renewable resource depletion Global warming Ozone depletion Acidification Eutrophication Photochemical oxidant formation Human toxicity Aquatic toxicity

Impact Assessment Characterisation Involves the quantification of the impact of interest relative to a reference substance. In the example we examined we look at the Global Warming Potential of the Products life cycle relative to CO2 emissions. Takes place using the formula eck,j represents the relative contribution of burden Bj to impact Ek

Interpretation This phase is aimed at system improvements and innovation and it includes the following steps Identification of major burdens and impacts Identification of ‘hot spots’ in the life cycle Sensitivity analysis Evaluation of findings and recommendations

Interpretation Sensitivity Analysis Indicates the level of reliability of the LCA Data availability and reliability Uncertainties Data gaps