There are many different terms with specific definitions relevant to life cycle assessment (LCA), techno-economic assessment (TEA), and carbon capture, utilization, and storage (CCUS) technologies.
Below is a list of external glossaries focused on LCA, TEA, and CCUS.
- Life Cycle Initiative Glossary of Life Cycle Terms
- International Life Cycle Academy Glossary
- U.S. Environmental Protection Agency LCA Principles and Practices Glossary
- Handbook on Life Cycle Assessment Part 2a Glossary (page 91)
- Consequential LCA Glossary and Definitions
- ecoinvent Glossary of ecoinvent Terminology
- AACE International Cost Engineering Terminology
- American University Carbon Removal Glossary
- Foresight Transitions Carbon Removal Glossary
- CO2 Capture Project Glossary
- ECO2 CCS Glossary
- Renewable Carbon Initiative Glossary
- Carbon Dioxide Removal Primer Glossary
The custom glossary below was created by the members of the International CCU Assessment Harmonization Group. Specific authors include Katy Armstrong, Lorenzo Cremonese, Evelyn Dale, Michele Mutchek, Leonard Müller, Barbara Olfe-Kräutlein, and Volker Sick. The group endorses the definitions featured on this page but recognizes that the other glossaries listed above may contain alternative terms or perspectives.
Italicization of a word or phrase within the below definitions indicates that the word or phrase is also featured in the glossary.
- Allocation
- Methodology to solve Multi-functionality that is usually applied if no other method to solve Multi-functionality is applicable (i.e., Subdivision, System expansion or Substitution). Allocation consists of partitioning the input or output flows of a Process or a Product system between the Product system under study and one or more other Product systems, on the basis of economic value, mass, energy, or other common characteristics across products (based on ISO 14040 3.17)
- Attributional LCA
- Life cycle inventory (LCI) modeling frame that inventories the inputs and output flows of all Processes of a system as they occur. Modeling Process along an existing supply-chain is of this type. Consequential LCA is an alternative approach to Attributional LCA (based on ILCD Handbook)
- Average GHG
- Environmental profile that represents the weighted mean GHG performance for production within the area that the Proposed product system will be deployed
- Basis for comparison
- Measure used to compare a product or technology with the Benchmark product. Commonly referred to as Functional unit (recommended)
- Basket of functions
- Used to describe a system or Process that produces multiple purposes (i.e., a Multi-functional system)
- Benchmark (product) system
- Defined reference system for comparison of the Proposed product system
- Benchmark product
- Product that the Product(s) of study competes against
- Best-in-class technology (BIC)
- Process or Product with superior performance. BIC can be used as a Benchmark against which the Process or Product investigated is compared. Note that BIC can be defined according to environmental, economic, or technical criteria
- Break-even point
- Point at which the return on investment and the investment coincides, being economic, environmental, social, or others. In the field of economics, the Break-event point is the production level at which total costs and total revenues coincide. At higher production volumes, the Product or technology will produce net profit. The Break-even point definition is similar to the Payback time
- Burden shifting
- Shifting environmental impacts from one Impact category, region, or Life cycle stage to another (e.g., from one company in a value chain to another)
- By-product
- Secondary product generated by a Unit process/System element or Product system together with the Primary product. Differently from Co-products, this term refers to Products that do not generate considerable revenues when compared to the Primary product
- CO2 capture cost
- Cost associated with capturing CO2 from a point source or atmosphere. It can include separation/purification and compression costs. Note: it is rare that CO2 capture costs are zero even if direct flue gas (no purification) is used, as pumping costs must be accounted for
- Capital cost
- See Capital expenditure
- Capital expenditure (CAPEX)
- Initial investment costs related to non-consumable parts of a plant or technology, such as investment in production, plant construction and equipment, engineering costs, and working capital. Capital expenditure is also referred to as Capital cost
- Carbon (Dioxide) Capture and Sequestration (CCS)
- See Carbon (Dioxide) Capture and Storage (CCS)
- Carbon (Dioxide) Capture and Storage (CCS)
- Process including the separation and removal of CO2 from the atmosphere (Direct Air Capture), fuel combustion, industrial processes, or similar; its potential transport via ship or pipeline; and its permanent storage via methods such as disposal in geological formations or mineralization. CCS can also refer to Carbon capture and sequestration
- Carbon (Dioxide) Capture and Utilization (CCU)
- Process including the separation and removal of CO2 from the atmosphere (Direct Air Capture), fuel combustion, or industrial processes; its transport via ship, train, truck, or pipeline; and its use as a resource to create valuable Products (e.g., plastic, beverages). Specifically for the steel sector, carbon monoxide (CO) can also be considered a CCU feedstock as well as CO2
- Carbon (Dioxide) Capture, Utilization, and Storage (CCUS)
- Process including the separation and removal of CO2 from the atmosphere (Direct Air Capture), fuel combustion, industrial processes, or similar; its transport via ship or pipeline; and either its use as a resource to create valuable Products (e.g., plastic) or its permanent storage deep underground in geological formations (CCS) or via methods such as mineralization. Specifically for the steel sector, carbon monoxide (CO) can also be considered a CCU feedstock as well as CO2. The term CCUS is widely used in North America to indicate different routes for handling the captured CO2
- Carbon (dioxide) recycling
- Indicates the Process of reutilizing CO2 as a source of carbon to produce goods. CO2 can be sourced from materials and fuels, and recycled by processes such as mineralization, artificial photosynthesis, and methanation. It is generally synonymous with CCU or CCUS. Although technically incorrect (as the term “recycling” implies physical or chemical conversion of the waste material considered), the term Carbon recycling is particularly useful to promote CCU or CCUS outside the practitioners’ sector
- Carbon Dioxide Removal (CDR)
- Suite of methods that extract CO2 from the ambient air by biological, chemical, or physical means
- Carbon Dioxide Utilization (CDU)
- Process including the use of CO2 as a resource to create valuable Products (e.g., plastic, concrete). CDU is generally synonymous with Carbon Capture and Utilization (CCU) or Carbon Capture, Utilization and Storage (CCUS)
- Carbon abatement cost
- Combined Indicator used to assess the environmental performance of new technologies against production costs. Specifically, Carbon abatement cost determines the costs associated to the reduction of a unitary amount of emissions (e.g., ton of CO2-eq), when a given reference technology is replaced by a new one (e.g., a CCU plant). Carbon abatement cost is also referred as to GHG abatement cost, and can be determined via the following formula:
Cabated = (CCCU - Cref) / (eiref - eiCCU)
Where:
CCCU = specific production costs of the CCU plant
Cref = specific production costs of the reference plant
eiref = specific environmental impact of the reference plant
eiCCU = specific environmental impact of the CCU plant
Please note that the result of this formula is significant only in the positive domain of the denominator
- Carbon avoided
- See Carbon reducing and GHG emission reducing
- Carbon negative
- Product, technology, or Process for which overall GHG emissions released to the atmosphere (measured via Cradle-to-grave analysis) are lower than the amount of GHGs captured from the atmosphere. This can occur when GHGs are captured from the atmosphere by biological, chemical, or physical means and are sequestered in geological reservoirs or permanently stored in a Product. Carbon negative products, technologies, or Processes are also referred to as Negative emissions technologies (NETs)
- Carbon neutral
- Product, technology, or Process for which overall GHG emissions released to the atmosphere (measured via Cradle-to-grave analysis) are equal to the amount of GHGs captured from the atmosphere. This can occur when GHGs captured from the atmosphere by biological, chemical, or physical means, and GHGs released at the end-of-life (including all additional emissions from raw material mining, processing, etc.) are offset. This can also occur when GHGs are captured from fossil point sources, and they are sequestered or permanently stored in the Product, while all other GHG emissions are zero over the entire Life cycle
- Carbon rainbow
- Color-coded system used to describe the origin of the carbon in a Product: black=fossil carbon, blue=marine carbon, green=carbon from biomass, purple= atmospheric CO2, and grey=carbon from waste materials. Similar categorizations also apply for hydrogen, ammonia, and naphtha
- Carbon reducing
- Product, technology, or Process for which overall CO2 emissions released to the atmosphere (measured via Cradle-to-grave analysis) are lower than those of the competing Product (i.e., Benchmark), under the same System boundaries. These bring a proven net contribution to mitigating climate change *only* when displacing the Benchmark (i.e., Carbon reducing technologies are not necessarily Carbon negative). Carbon reducing is also occasionally referred to as Carbon avoided, and it is a variant of GHG emission reducing
- Characterization factor
- Quantifies the environmental impact within an Impact category relative to a reference substance (e.g., CO2 contribution to climate change is expressed by the Global Warming Potential (GWP))
- Co-product
- Secondary Product generated by a Unit process or Product system together with the Primary product. Different from By-product, this term refers to Products that generate considerable revenues when compared to the Primary product
- Combined assessment
- Integration of at least two of TEA, LCA, and Social impact assessment to systematically analyze the relationship between technological, economic, social, and environmental criteria and Indicators. This integration enables derivation of goal-driven insights and a balancing of trade-offs between technological, economic, social, and environmental aspects to determine optimal solutions. Combined assessment is also referred as Integration
- Commissioner
- Organization or individual that commissions a TEA or LCA study
- Comparison case
- See Comparison product system
- Comparison process
- Systems in the Comparison product system that produce equivalent functions to the system(s) in the Proposed product system
- Comparison product system
- Entire Life cycle boundary of the model that will be compared to the Proposed product system. The Comparison product system (recommended) case is occasionally defined as Comparison case
- Consequential LCA
- Life cycle inventory (LCI) modeling approach that identifies how activities in a Product system may alter in consequence to decisions within the system. An example could be how flows change with a change in demand for the Functional unit. Consequential LCA is an alternative approach to Attributional LCA
- Contingency costs
- Category of Capital costs that are expected to occur as an actual project moves toward completion. These can be divided in process and project Contingency costs. The process Contingency costs account for the level of maturity of a particular Process or component within the plant (such as a CO2 capture system). It attempts to quantify the additional Capital costs that will likely arise as a Process matures into a full-scale commercial technology. The project Contingency costs are an additional factor that accounts for the cost of equipment or other costs that would be identified in a more detailed design of a definitive project at a particular site. These costs apply to the overall project and not to individual plant components
- Cost increment
- Cost relative to one additional unit of production, that is the cost of producing one more unit of a good. Cost increment is also indicated as Incremental cost or Marginal cost
- Cost of goods manufactured (COGM)
- Production costs of the good. It includes Capital expenditures (CAPEX) and Operational expenditures (OPEX) of direct materials, direct labor, and manufacturing overhead
- Cost of goods sold (COGS)
- Direct costs of producing the goods sold by a company. Cost of goods sold are obtained by adding potential freight, other overheads, delivery costs, and marketing to the Cost of goods manufactured (COGM)
- Cradle, gate, grave
- Stages/boundaries within which the assessment is conducted. They define the System boundary. Cradle: very origin of the process; Grave: dispose of ultimate waste; Gate: specific boundary within the system (e.g., factory gates or delivery point). The System boundary has to be accurately defined, in particular to ensure a comprehensive climate Impact assessment (i.e., Cradle-to-grave). Moreover, sound comparisons of two or more technologies or Products can be conducted only if the same System boundaries are considered
- Cut-off criteria
- Amount of material or energy flow or the level of significance associated with Unit processes or Product system to be excluded from a study. For example, the practitioner may consider excluding costs or impacts when conducting a study if they do not contribute to more than 1% to the overall results (based on ISO 14040 3.18)
- Direct Air Capture (DAC)
- Method to capture CO2 from ambient air
- Discount rate
- Interest rate used to adjust for the time value of money, and charged for the financial loan
- Elementary flow
- Used only in LCA. Material or energy entering the system being studied that has been drawn from the environment without previous human transformation, or material or energy leaving the system being studied that is released into the environment without subsequent human transformation (based on ISO 14040 3.12)
- Endpoint (and midpoint)
- Location along the impact pathway of a Life cycle that is used to derive a Characterization factor. For example, a Midpoint for climate change is Global Warming Potential (GWP), while an Endpoint for climate change is the translated human health impact
- Energy flow
- Energy input to or output from a Unit process or Product system, quantified in energy units (based on ISO 14040 3.13)
- Factored estimation
- Procedure of multiplying an item by a given factor for the estimation of another cost item
- Feedstock
- Primary or Secondary raw material that is used to produce a Product or to supply or fuel a machine or industrial Process
- First-of-a Kind (FOAK)
- First item or generation of items using a new technology or design. Generally, FOAK plants cost significantly more than later items or generations, which are called NOAK for nth-of-a-kind
- Functional unit
- Quantifies the technical performance of a Product or system and must be defined unambiguously to ensure meaningful comparison with alternatives. Functional units can be defined by mass, energy, or service according to the applications chosen. The Functional unit also serves as a reference system to ensure that comparisons between systems serve equal functions. Examples of Functional units are: tons of methanol produced per plant, kWh generated per unit of time, etc.
- GHG abatement cost
- See Carbon abatement cost
- GHG emission reducing
- Product, technology, or Process for which overall GHG emissions released to the atmosphere (measured via Cradle-to-grave analysis) are lower than those of the competing product (i.e., Benchmark), under the same System boundaries. These bring a proven net contribution to mitigating climate change *only* when displacing the Benchmark (i.e., they are not necessarily Carbon negative). GHG emission reducing is similar to Carbon reducing and Carbon avoided
- Global Warming Potential (GWP)
- Measures of how much energy the emissions of 1 kg of a given gas will absorb over a given period of time, relative to the emissions of 1 kg of CO2. GWP are used to compare the relative impact of different greenhouse gases (GHGs) on climate forcing, and they are usually relative to a time-horizon of 20 or 100 years
- Goal
- First stage of a TEA or LCA that states the intended application of the study, the reasons for carrying it out, the intended audience, and how the results are to be used
- Highest market share
- Defines the representativeness of the Comparison product system as the Product or Service most common in the commercial marketplace; also referred to as the Industry standard practice
- Hotspot
- Process or input that has a significant influence on the technical, economic (for TEA), or environmental (for LCA) performance of the plant or Process. Common hotspots in Carbon capture and utilization (CCU) generally include carbon capture, electricity source and price, hydrogen production, preparation of materials (particularly in mineralization), Product separation, and even end-of-life phases
- Impact assessment (in LCA)
- Phase of LCA aimed at understanding and evaluating the magnitude and significance of the potential environmental impacts for a Product system throughout the Life cycle of the product (from ISO 14040 3.4)
- Impact category
- Groups individual effects of a Process or Product that impact the same economic or environmental category (e.g., variable costs, acidification, global warming). The term Impact category is mostly used in LCA studies
- Impact category indicator (LCA)
- See Indicator (TEA)
- Incremental cost
- See Cost increment
- Indicator (TEA)/Impact category indicator (LCA)
- Parameter that measures the performance of a Product with respect to a specific economic or environmental category (e.g., global warming). One or more indicators can be used for the same Impact category (e.g., CO2, CH4, and N2O emissions are all indicators relevant for the climate Impact category)
- Industry standard practice
- Identifies the method(s) of production of Comparison product system that represents Standard industry practices for production. Generally, this is equivalent to the method with the highest production of a Product or Service
- Input flow
- Input material or energy flows crossing the System boundary
- Integration
- See Combined assessment
- Intermediate
- Material or energy output from a System element/Unit process that requires further transformation in another System element/Unit process within the system (based on ISO 14040 3.23)
- Internal rate of return (IRR)
- Discount rate that leads to a zero Net present value (NPV). IRR is used to evaluate financial viability of a potential investment over a specific period
- Interpretation
- Phase of LCA or TEA in which the findings of either the Inventory analysis or the Impact assessment, or both, are evaluated in relation to the defined Goal and Scope in order to reach conclusions and recommendations (from ISO 14040 3.5)
- Inventory (for TEA)/Inventory analysis or LCI (for LCA)
- Collection of all relevant data that will be used to produce the results. The Inventory summarizes all relevant technical as well as economic parameters and assumptions of the Product and Benchmark systems, such as equipment, material, and energy flows; information about the context (temporal, regional, economic) of the studied Scenario; transport or waste; and their assigned prices and market volumes
- Learning curve
- Learning curve defines the reduction rate of economic and environmental Indicators through iterative improvements of the technology during development and deployment stages. The Learning curve is a measure of increased efficiencies in the overall process. Labor efficiency, standardized manufacturing, optimization of Product design, and scales are factors that define the overall efficiency and thus the Learning curve
- Life cycle
- Consecutive and interlinked stages of a Product system, from Raw material acquisition or generation from natural resources to final disposal (from ISO 14040 3.1)
- Life cycle analysis
- See Life cycle assessment (LCA)
- Life cycle assessment (LCA)
- Compilation and evaluation of the inputs, outputs, and the potential environmental impacts of a Product system throughout its Life cycle (from ISO 14040 3.2). According to the Impact category investigated, examples of common LCA indicators can be the amount of CO2-eq emissions per unit of Product, amount of freshwater used per kg of product, etc. LCA is usually also referred to as Life cycle analysis
- Life cycle assessment phase (or stage)
- Analysis task to be fulfilled when conducting an LCA. The principal steps are Goal and Scope definition, Inventory analysis, Impact assessment, and Interpretation
- Life cycle costing (LCC)
- Life cycle costing (LCC) is an approach that assesses the total cost of an asset over its life cycle including initial Capital expenditures (CAPEX), maintenance expenditures, Operating expenditures (OPEX), and the asset’s residual value at the end of its life. Life cycle costing aims at cost analysis along all Life cycle stages of a Product, while TEA is typically limited to an inherent investor-perspective with Cradle-to-gate System boundaries
- Life cycle impact assessment (LCIA)
- See Impact assessment (in LCA)
- Life cycle inventory (LCI)
- See Inventory (for TEA)
- Life cycle inventory assessment
- See Impact assessment (in LCA)
- Marginal costs
- See Cost increment
- Material flow
- Material input in or output from a Unit process/System element or Product system, quantified in mass/volume unit
- Midpoint
- See Endpoint
- Multi-criteria decision analysis (MCDA)
- Method that allows the evaluation of trade-offs, and thus supports decisions involving multiple dimensions or criteria. This method allows systematic evaluation of multiple criteria (including competing priorities), the interdependencies among them, and their impact on the outcome of the Process analysis
- Multi-functionality
- Several input functions to a given Unit process/System element, or several applications of the functional flow generated by Unit process/System element. It applies to Product systems where there are multiple Products to be dealt with
- NOAK (nth of a kind)
- Further (nth) item or generation of items using a technology or design. Due to factors like economies of scale and technology Learning curves, NOAK plants cost significantly less than first items or generations, which are called FOAK
- Negative emissions technologies (NETs)
- See Carbon negative. May also refer to non-carbon emissions (e.g., including air pollutants, and others)
- Net present value (NPV)
- Sum of all cash inflows and outflows over the period of interest, based on an assigned Discount rate
- Non-substitute
- Product with a structure or chemical characteristics different to the Reference product (i.e., Benchmark). This means that the functional properties are not equal and therefore the Product cannot be compared without adjustments. The distinction between a Non-substitute and a Substitute is fundamental for the definition of Functional units and Reference flows
- Normalization
- In a general sense, Normalization describes any mathematical operation that adjust values on different scales (different units) to be on the same scale (same units), so that they can be compared. This sense of Normalization is commonly used in LCA and TEA at various stages of an analysis.
In LCA, Normalization often formally refers to an optional step in an Impact assessment where all of the characterization results (e.g., kg CO2 equivalents [CO2-eq]/kg Product [GWP] and kg Nitrogen equivalents [N]/kg Product [Eutrophication potential]) are divided by Normalization factors that allow all of the characterization results to be on the same scale (same units) and thus comparable to each other. For example, by estimating the total Global Warming Potential (GWP) and Eutrophication Potential of all economic activities in a region and year (e.g., global CO2-eq and N in 2020 expressed as kg CO2-eq/yr and kg N/yr), characterization results can be divided by those Normalization factors to result in a common unit of yr/kg Product
- Operational cost
- See Operational expenditure (OPEX)
- Operational expenditure (OPEX)
- Expenses expected for the operation of a technology or for the production of goods. Operational expenditure can be divided into variable costs and fixed costs. Variable costs depend directly on the amount of Product produced (e.g., Raw materials, energy, utilities, waste disposal). On the other hand, fixed costs do not directly depend on the amount of Product produced but can indirectly be influenced by it, for example via the plant size. Operational expenditure is also referred to as Operational cost
- Output flow
- Material flows or Energy flows exiting the System boundary
- Payback time (or payback period)
- Timespan required to pay back the capital invested in a project via the net cash inflows. From this point onward, the Product or technology will produce net profit. Payback time is calculated as Capital expenditure divided by the annual profit resulting from plant operation and Product selling. The terms Payback time and Break-even point are very similar
- Phase of assessment
- Analysis task to be fulfilled when conducting an assessment
- Plausibility check
- Basic test to evaluate whether a claim or the result of a calculation can possibly be true. It is recommended to use this term instead of Sanity check
- Practitioner
- Person with sufficient technical background and experience to conduct a TEA or an LCA
- Primary raw material
- Material used to produce a Product in its very original form occurring in nature (e.g., minerals)
- Process
- Set of interrelated or interacting activities that transforms energy and material inputs into outputs (based on ISO 14040 3.11)
- Product
- Output of a Process, event, or a combination of these, that is the object of analysis in the TEA/LCA study. In this glossary, this is inclusive of a Service
- Product system
- Collection of Processes (e.g., chemical, biological, physical, etc.) required to provide the final Product(s) across one or multiple stages of the Life cycle
- Proposed case
- See Proposed product system
- Proposed process
- Systems in the Proposed product system that produce equivalent functions to the system(s) in the Comparison product system
- Proposed product system
- Entire Life cycle boundary of the carbon utilization product or service as defined by the Functional unit of the analysis. The Proposed product system (recommended) is occasionally defined as Proposed case
- Raw material
- Material input (including recycled materials) that is used to produce a Product (based on ISO 14040 3.15). Raw material can be Primary or Secondary raw material
- Rebound effect
- Relates to cases where a reduction in predicted gains (environmental or economic) is observed due to the new Product triggering a change in purchase or consumption, thus canceling out some of (or all) the expected benefits
- Reference (product) system
- See Benchmark (product) system
- Reference flow
- Relevant output in a given system that is required to fulfill the function expressed by the Functional unit (e.g., the amount of paint [Reference flow] required to cover a defined area at a defined opacity [Functional unit]). Since Product systems can also serve more than one function (e.g., a combined heat and power system provides both electricity and heat), Functional units might contain more than one Reference flow that pertains to the Scope of the assessment
- Renewable carbon
- Carbon that is part of a circular system with a turnover time of less than geological time scales (e.g., atmospheric CO2, biomass, plastics)
- Reporting
- Presentation of LCA or TEA study that reports, assesses, and interprets results. This step is particularly important as it communicates the results of the study to the Commissioner
- Return on investment (ROI)
- Performance Indicator used to measure the profitability of an investment. It is determined by the ratio between the net income (i.e., difference between current value and Capital expenditures) and initial Capital expenditures (CAPEX)
- Sanity check
- See Plausibility check
- Scenario
- Alternative—although not equally likely—states of the world, which represent plausible conditions under different assumptions. Scenarios define the conditions and settings “external” to the process or product analyzed, and in which the Carbon Capture Utilization and Storage (CCUS) technology is assumed to operate under
- Scenario analysis
- Evaluation of sets of alternative Scenarios in relation to the model results for the baseline Scenario. Best- and worst-case Scenarios can be defined to quantify the range of the model results. A Scenario analysis can for example show the dependence of results on clean energy supply or location
- Scope
- Second stage of a TEA or LCA that determines which aspects of a Process or Product will be assessed. This mainly includes the selection of the subject for analysis, the specification of comparison metrics, the System elements/Unit processes required, and selection of the System boundary. All these items have to be selected according to the Technological maturity level of the Product system
- Secondary raw material
- Recycled or reworked material used to produce a Product
- Sensitivity analysis (SA)
- Examination of the variation of the model output by changing the magnitude of one or more input variables
- Sequestration time
- Storage timespan of CO2 when converted into different Products (e.g., as mineral, fuel, etc.) or stored underground. Permanent sequestration can only be considered for CO2 that has the potential to be stored for geological time periods
- Service
- Term used when defining a Functional unit to describe the need to be met, for example transport or heat. In this glossary, a Service can be thought of as a Product
- Social impact assessment (SIA)
- Analyzes the intended or unintended consequences of new actions across the Life cycle of the product to humans. For a comprehensive sustainability assessment, Social impact assessment (SIA) (or Social life cycle assessment [S-LCA]) can be combined with LCA and TEA
- Social life cycle assessment (S-LCA)
- See Social impact assessment (SIA)
- Stakeholder
- Actor who has a relation with a Process, Product, or event
- Subdivision
- Methodology to solve Multi-functionality that consists of disaggregating a Process into smaller units. Subdivision is usually the first option among all methods (i.e., the other methodologies are Substitution, System expansion, and Allocation)
- Substitute
- Product with the same structure or chemical characteristics as to the Benchmark (product) system. This means, that the functional properties are equal and therefore the Product can be compared without adjustments. The distinction between a Non-substitute and a Substitute is fundamental for the definition of Functional units and Reference flows
- Substitution
- Methodology to solve Multi-functionality that is generally applied if Subdivision or System expansion are not applicable
- System boundary
- Sets the limits of the Product system, and defines which System elements or Unit processes belong to it. The System boundary must be selected in line with the overall Goal and Scope of the assessment
- System element
- Modeling component of the Product system. A System element can be hardware, software, data, humans, Processes (e.g., Processes for providing services to users), procedures (e.g., operator instructions), facilities, materials, naturally occurring entities (e.g., water, organisms, minerals), or any combination of these. System element is particularly used in TEA and is equivalent to Unit process in LCA
- System expansion
- Methodologies for solving Multi-functionality that is usually applied if Subdivision is not applicable. It consists in expanding Functional units to include other functions of the Product systems
- Techno-economic assessment (TEA)
- Provides information on the economics of a given Process or Product associated with a specific location and time period, along with their accuracy and variability over time due to technological developments or future Scenario conditions. Through a complete TEA it is possible to evaluate if an innovative Process or Product is economically feasible under the conditions/Scenarios considered, which Processes or steps are technological or economic Hotspots, and how performance relates to competing options. Commonly used Indicators for TEA studies include total costs of production per unit of Product or per unit of energy
- Technology maturity
- Stage of development of a Product system or of a System element/Unit process. Technology maturity can refer to three main categories: applied research, development, and deployment. A common system to define Technology maturity is using the Technology readiness level scale
- Technology readiness level (TRL)
- Systematic qualitative scaling method that defines the Technology maturity. Technology readiness level (TRL) is subdivided in 9 levels with 1 corresponding to the lowest maturity (basic concept) and 9 corresponding to deployment of the technology (commercial-scale technology)
- Uncertainty analysis
- Method to analyze (and ideally to quantify) the ranges of uncertainties contained within the model which affect the outputs. Monte Carlo simulations are one example of Uncertainty analysis
- Unit process (or system element)
- Smallest element considered in the Life cycle inventory (LCI) analysis for which input and output data are quantified (from ISO 14040 3.34). Unit process in LCA is equivalent to System element in TEA
- Waste product
- Product generated by a Unit process or Product system together with the Primary product, which does not generate any revenues and usually requires treatment before disposal
- Weighted average cost of capital (WACC)
- Calculation of a firm’s cost of capital in which each category of capital is proportionately weighted. The cost of capital is the rate a company is expected to pay on average to all its security holders to finance its assets. According to the financial system adopted by the company, weighted average cost of capital is estimated via average weight of costs of equity, costs of debt, or a blend of them