In this essay we will discuss about Life Cycle Assessment (LCA). After reading this essay you will learn about:- 1. Meaning of Life Cycle Assessment 2. Purpose of Life Cycle Assessment 3. Phases 4. Uses and Tools 5. Types 6. Economic Input-Output 7. Ecologically-Based 8. Life Cycle Energy Analysis.
Essay on Life Cycle Assessment (LCA)
Essay Contents:
- Essay on the Meaning of Life Cycle Assessment
- Essay on the Purpose of Life Cycle Assessment
- Essay on the Phases of Life Cycle Assessment
- Essay on the Uses and Tools of Life Cycle Assessment
- Essay on the Types of Life Cycle Assessment
- Essay on Economic Input-Output Life Cycle Assessment
- Essay on Ecologically-Based Life Cycle Assessment
- Essay on the Life Cycle Energy Analysis
Essay # 1. Meaning of Life Cycle Assessment (LCA):
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A life cycle assessment (LCA, also known as life cycle analysis, eco balance, and cradle-to-grave analysis) is a technique to assess each and every impact associated with all the stages of a process from cradle-to-grave (i.e., from raw materials through materials processing, manufacture, distribution, use, repair and maintenance and disposal or recycling). LCA’s can help avoid a narrow outlook on environmental, social and economic concerns.
This is achieved by:
i. Compiling an inventory of relevant energy and material inputs and environmental releases.
ii. Evaluating the potential impacts associated with identified inputs and releases.
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iii. Interpreting the results to help you make a more informed decision.
Essay # 2. Purpose of Life Cycle Assessment:
The goal of LCA is to compare the full range of environmental and social damages assignable to products and services, to be able to choose the least burdensome one. At present it is a way to account for the effects of the cascade of technologies responsible for goods and services.
It is limited to that, though, because the similar cascade of impacts from the commerce responsible for goods and services is unaccountable because what people do with money is unrecorded. As a consequence LCA succeeds in accurately measuring the impacts of the technology used for delivering products, but not the whole impact of making the economic choice of using it.
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The term ‘life cycle’ refers to the notion that a fair, holistic assessment requires the assessment of raw material production, manufacture, distribution use and disposal including all intervening transportation steps necessary or caused by the product’s existence.
The sum of all those steps – or phases – is the life cycle of the product. The concept also can be used to optimize the environmental performance of a single product (eco design) or to optimize the environmental performance of a company.
Common categories of assessed damages are global warming (greenhouse gases), acidification (soil and ocean), smog, ozone layer depletion, eutrophication, eco-toxicological and human-toxicological pollutants, habitat destruction, desertification, land use as well as depletion of minerals and fossil fuels.
The procedures of life cycle assessment (LCA) are part of the ISO 14000 environmental management standards: in ISO 14040:2006 and 14044:2006. (ISO 14044 replaced earlier versions of ISO 14041 to ISO 14043.)
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Essay # 3. Phases of Life Cycle Assessment:
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According to the ISO 14040 and 14044 standards, a Life Cycle Assessment is carried out in four distinct phases. These are often interdependent in that the results of one phase will inform how other phases are completed.
(i) Goal and Scope:
In order to make efficient use of time and resources and outline how the study will be conducted and what final results will be obtained, the following six decisions must be made at the beginning of the LCA process:
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(1) Define the goal(s) of the project
(2) Determine what type of information is needed to inform the decision-makers
(3) Determine the required specificity
(4) Determine how the data should be organized and the results displayed
(5) Define the scope of the study, and
(6) Determine the ground rules for performing the work.
In the first phase, the LCA-practitioner formulates and specifies the goal and scope of study in relation to the intended application. The object of study is described in terms of a so-called functional unit. Apart from describing the functional unit, the goal and scope should address the overall approach used to establish the system boundaries.
The system boundary determines which unit processes are included in the LCA and must reflect the goal of the study. In recent years, two additional approaches to system delimitation have emerged. These are often referred to as ‘consequential’ modeling and ‘attributional’ modeling. Finally the goal and scope phase includes a description of the method applied for assessing potential environmental impacts and which impact categories that are included.
(ii) Life Cycle Inventory:
The second phase of Life Cycle Inventory (LCI) involves data collection and modeling of the product system, as well as description and verification of data. This encompasses all data related to environmental (e.g., CO2) and technical (e.g., intermediate chemicals) quantities for all relevant unit processes within the study boundaries that compose the product system.
Examples of inputs and outputs quantities include inputs of materials, energy, chemicals and ‘other’ – and outputs of air emissions, water emissions or solid waste. Other types of exchanges or interventions such as radiation or land use can also be included.
Usually, Life Cycle Assessment inventories and modeling are carried out using a dedicated software package, such as SimaPro or GaBi. All LCA software attempts to analyze every stage of the product’s life cycle, based on data input by the decision-maker. Again, a life cycle analysis is only as valid as its data.
Thus, it is necessary for the decision-maker to first have an extensive knowledge or access to the details of the product “cradle-to-grave”– resource extraction, product manufacture, use, and disposal. Depending on the software package employed, it is possible to model not only the environmental impacts of each stage in the product’s life, but also the underlying costs and social impacts. The software program can be designed to assess the life cycle holistically or with a specific aspect in mind, such as optimal recyclability or waste minimization.
The data must be related to the functional unit defined in the goal and scope definition. Data can be presented in tables and some interpretations can be made already at this stage. The results of the inventory is an LCI which provides information about all inputs and outputs in the form of elementary flow to and from the environment from all the unit processes involved in the study.
(iii) Life Cycle Impact Assessment:
The third phase ‘Life Cycle Impact Assessment’ is aimed at evaluating the contribution to impact categories such as global warming, acidification, etc. The first step is termed characterization. Here, impact potentials are calculated based on the LCI results. The next steps are normalization and weighting, but these are both voluntary according the ISO standard.
Normalization provides a basis for comparing different types of environmental impact categories (all impacts get the same unit). Weighting implies assigning a weighting factor to each impact category depending on the relative importance. The weighting step is not always necessary to create a so called ‘single indicator’. See for instance the prevention based model of the eco-costs.
(iv) Interpretation:
The phase stage ‘interpretation’ is an analysis of the major contributions, sensitivity analysis and uncertainty analysis. This stage leads to the conclusion whether the ambitions from the goal and scope can be met.
Life Cycle Interpretation is a systematic technique to identify, quantify, check, and evaluate information from the results of the life cycle inventory (LCI) and/or the life cycle impact assessment (LCIA)…. The purpose of performing life cycle interpretation is to determine the level of confidence in the final results and communicate them in a fair, complete, and accurate manner. Interpreting the results of a life cycle assessment (LCA) is not as simple.
Interpreting the results of an LCA starts with understanding the accuracy of the results, and ensuring they meet the goal of the study. This is accomplished by identifying the data elements that contribute significantly to each impact category, evaluating the sensitivity of these significant data elements, assessing the completeness and consistency of the study, and drawing conclusions and recommendations based on a clear understanding of how the LCA was conducted and the results were developed.
Essay # 4. Uses and Tools of Life Cycle Assessment:
Based on a survey of LCA practitioners carried out in 2006 most life cycle assessments are carried out with dedicated software packages. 58% of respondents used GaBi Software, developed by PE International, 31% used SimaPro developed by PRe Consultants, and 11% a series of other tools.
According to the same survey, LCA is mostly used to support business strategy (18%) and R&D (18%), as input to product or process design (15%), in education (13%) and for labelling or product declarations (11%).
An example of LCAs application to labelling is the International Organization of Standardization’s ‘Eco-labelling’ program, which identifies environmental preference for a product or service based on life cycle considerations.
Data Analysis:
A life cycle analysis is only as valid as its data; therefore, it is crucial that data used for the completion of a life cycle analysis is accurate and current. When comparing different life cycle analyses with one another, it is crucial that equivalent data is available for both products and processes in question. If one product has a much higher availability of data, it cannot be justify compared to another product which has less detailed data.
The validity of data should always be a concern with life cycle analyses. Since we are living in a global world and economy, new processes, manufacturing methods, and materials are introduced to various processes and products.
Therefore, it is important to have current data when performing a LCA. If data from 5 to 10 years in the past is used, the LCA will not be accurate, because the quantitative analysis will not reflect the current methods utilized in the process or product.
Therefore, drawing conclusions from a report using such data will be ineffective, since the data is unavailable. Some products, whose processes have not changed in 5 to 10 years (if there are any) will be exempt from this.
When analyzing electronics, such as cell phones or computers, for example, the most current data is necessary. Since new computer and cell phone models are created every few months, the results of a life cycle analysis of a 3-year-old computer system will often not be applicable to current systems.
One of the most important parts of LCA data analysis is determining the most costly portion of the life cycle. The life cycle considered usually consists of four stages embedded energy due to processing raw materials, materials processing and manufacturing, product use, and product disposal. If the most costly of these four stages can be determined, then impact on the environment can be efficiently reduced by focusing on making changes of that particular phase.
For example, the most energy-intensive life phase of an airplane or car is during use due to fuel consumption. One of the most effective ways to increase fuel efficiency is to decrease vehicle weight, and thus, car and airplane manufacturers can decrease environmental impact in a significant way by replacing aluminium with lighter materials such as carbon fibre reinforced fibres. The reduction during the use phase should be more than enough to balance additional raw material or manufacturing cost.
Essay # 5. Types of Life Cycle Assessment:
(i) Cradle-to-Grave:
Cradle-to-grave is the full Life Cycle Assessment from manufacture (‘cradle’) to use phase and disposal phase (‘grave’). For example, trees produce paper, which can be recycled into low-energy production cellulose (fiberised paper) insulation, then used as an energy-saving device in the ceiling of a home for 40 years, saving 2,000 times the fossil-fuel energy used in its production. After 40 years the cellulose fibers are replaced and the old fibers are disposed of, possibly incinerated. All inputs and outputs are considered for all the phases of the life cycle.
(ii) Cradle-to-Gate:
Cradle-to-gate is an assessment of a partial product life cycle from manufacture (‘cradle’) to the factory gate (i.e., before it is transported to the consumer). The use phase and disposal phase of the product are usually omitted.
Cradle-to-gate assessments are sometimes the basis for environmental product declarations (EPD) defined as “quantified environmental data for a product with pre-set categories of parameters based on the ISO 14040 series of standards, but not excluding additional environmental information”.
(iii) Cradle-to-Cradle:
Cradle-to-cradle is a specific kind of cradle-to-grave assessment, where the end-of-life disposal step for the product is a recycling process. It is a method used to minimize the environmental impact of products by employing sustainable production, operation, and disposal practices and aims to incorporate social responsibility into product development.
From the recycling process originate new, identical products (e.g., asphalt pavement from discarded asphalt pavement, glass bottles from collected glass bottles), or different products (e.g., glass wool insulation from collected glass bottles).
Products can now obtain a cradle-to-cradle certification level. Cradle-to-cradle certification evaluates products based on 5 categories including material health, material reutilization, renewable energy use water stewardship, and social responsibility.
The ideal cradle-to-cradle product would have little to no human health risk, be recycled in a closed loop design, be created using solar or other renewable energy, have no impact on local water sources, and be designed in a way that respects the rights of the people of our planet.
(iv) Gate-to-Gate:
Gate-to-gate is a partial LCA looking at only one value-added process in the entire production chain. Gate-to-gate modules may also later be linked in their appropriate production chain to form a complete cradle-to-gate evaluation.
(v) Well-to-Wheel:
Well-to-wheel is the specific LCA of the efficiency of fuels used for road transportation. The analysis is often broken down into stages titled ‘well-to-station’, or ‘well-to-tank’, and ‘station-to-wheel, or ‘tank-to-wheel’. The first stage, which incorporates the feedstock and fuel processes is sometimes called the ‘upstream’ stage, while the latter stage that deals with vehicle operation is sometimes called the ‘downstream’ stage.
The factor “TP = Petroleum refining and distribution efficiency = 0.830″ from the DOE regulation accounts for the ‘well-to-station’ portion of the gasoline fuel cycle in the USA. To convert a standard Monroney sticker value to a full cycle energy equivalent, convert with Tp. For example, the Toyota Corolla is rated at 28 mpg station-to-wheel.
To get the full cycle value, multiply mpg by TP = 0.83 to account for the refining and transportation energy use – 23.2 mpg full cycle. The same adjustment applies to all vehicles fueled completely with gasoline, therefore, Monroney sticker numbers can be compared to each other with or without the adjustment. A recent study examined well-to-wheels energy and emission effects of various vehicle and fuel systems.
The well-to-wheel variant has a significant input on a model developed by the Argonne National Laboratory. The Greenhouse gases, Regulated Emissions, and Energy use in Transportation (GREET) model was developed to evaluate the impacts of new fuels and vehicle technologies.
The model evaluates the impacts of fuel use using a well-to-wheel evaluation while a traditional cradle-to-grave approach is used to determine the impacts from the vehicle itself. The model reports energy use, greenhouse gas emissions, and six additional pollutants such as volatile organic compounds (VOCs) and carbon monoxide (CO).
Essay # 6. Economic Input-Output Life Cycle Assessment:
Economic input-output LCA (EIO-LCA) involves use of aggregate sector-level data on how much environmental impact can be attributed to each sector of the economy and how much each sector purchases from other sectors.
Such analysis can account for long chains (for example, building an automobile requires energy, but producing energy requires vehicles, and building those vehicles requires energy, etc.), which somewhat alleviates the scoping problem of process LCA; however, EIO-LCA relies on sector-level averages that may or may not be representative of the specific subset of the sector relevant to a particular product and therefore is not suitable for evaluating the environmental impacts of products. Additionally the translation of economic quantities into environmental impacts is not validated.
Essay # 7. Ecologically-Based Life Cycle Assessment:
While a conventional LCA uses many of the same approaches and strategies as an Eco-LCA, the latter considers a much broader range of ecological impacts. It was designed to provide a guide to wise management of human activities by understanding the direct and indirect impacts on ecological resources and surrounding ecosystems.
Developed by Ohio State University Center for resilience, Eco-LCA is a methodology that quantitatively takes into account regulating and supporting services during the life cycle of economic goods and products. In this approach services are categorized in four main groups- supporting, regulating provisioning and cultural services.
Essay # 8. Life Cycle Energy Analysis:
Life cycle energy analysis (LCEA) is an approach in which all energy inputs to a product are accounted for, not only direct energy inputs during manufacture, but also all energy inputs needed to produce components, materials and services needed for the manufacturing process. An earlier term for the approach was energy analysis.
With LCEA, the total life cycle energy input is established.
Energy Production:
It is recognized that much energy is lost in the production of energy commodities themselves, such as nuclear energy, photovoltaic electricity or high-quality petroleum products. Net energy content is the energy content of the product minus energy input used during extraction and conversion, directly or indirectly.
A controversial early result of LCEA claimed that manufacturing solar cells requires more energy than can be recovered in using the solar cell. The result was refuted. Another new concept that flows from life cycle assessments is Energy Cannibalism.
Energy Cannibalism refers to an effect where rapid growth of an entire energy-intensive industry creates a need for energy that uses (or cannibalizes) the energy of existing power plants. Thus during rapid growth the industry as a whole produces no energy because new energy is used to fuel the embodied energy of future power plants. Work has been undertaken in the UK to determine the life cycle energy (alongside full LCA) impacts of a number of renewable technologies.
Energy Recovery:
If materials are incinerated during the disposal process, the energy released during burning can be harnessed and used for electricity production. This provides a low-impact energy source, especially when compared with coal and natural gas. While incineration produces more greenhouse gas emissions than land filling, the waste plants are well-fitted with filters to minimize this negative impact.
A recent study comparing energy consumption and greenhouse gas emissions from land filling (without energy recovery) against incineration (with energy recovery) found incineration to be superior in all cases except for when landfill gas is recovered for electricity production.
Limitations of LCEA:
A criticism of LCEA is that it attempts to eliminate monetary cost analysis, that is replace the currency by which economic decisions are made with an energy currency.
It has also been argued that energy efficiency is only one consideration in deciding which alternative process to employ, and that it should not be elevated to the only criterion for determining environmental acceptability; for example, simple energy analysis does not take into account the renewability of energy flows or the toxicity of waste products; however the life cycle assessment does help companies become more familiar with environmental properties and improve there environmental system.
Incorporating Dynamic LCAs of renewable energy technologies (using sensitivity analyses to project future improvements in renewable systems and their share of the power grid) may help mitigate this criticism.
A problem the energy analysis method cannot resolve is that different energy forms (heat, electricity, chemical energy etc.) have different quality and value even in natural sciences, as a consequence of the two main laws of thermodynamics.
A thermodynamic measure of the quality of energy is energy. According to the first law of thermodynamics, all energy inputs should be accounted with equal weight, whereas by the second law diverse energy forms should be accounted by different values.
The conflict is resolved in one of these ways:
i. Value difference between energy inputs is ignored,
ii. A value ratio is arbitrarily assigned (e.g., a joule of electricity is 2.6 times more valuable than a joule of heat or fuel input),
iii. The analysis is supplemented by economic (monetary) cost analysis,
iv. Energy instead of energy can be the metric used for the life cycle analysis.
Critiques:
Life-cycle analysis is a powerful tool for analyzing commensurable aspects of quantifiable systems. Not every factor, however, can be reduced to a number and inserted into a model. Rigid system boundaries make accounting for changes in the system difficult. This is sometimes referred to as the boundary critique to systems thinking.
The accuracy and availability of data can also contribute to inaccuracy. For instance, data from generic processes may be based on averages, unrepresentative sampling, or out-dated results. Additionally, social implications of products are generally lacking in LCAs. Comparative life-cycle analysis is often used to determine a better process or product to use.
However, because of aspects like differing system boundaries, different statistical information, different product uses, etc. these studies can easily be swayed in favour of one product or process over another in one study and the opposite in another study based on varying parameters and different available data. There are guidelines to help reduce such conflicts in results but the method still provides a lot of room for the researcher to decide what is important, how the product is typically manufactured, and how it is typically used.