To perform the impact assessment, various scientific LCIA methods exist. Depending on goal and scope of your study and other aspects, specific methods are used. Here we provide a small overview of most common methods and the impacts they cover:
As displayed above, some impact methods only cover one specific impact category but represent also the fundation of other methods, e.g. IPCC is used in the Environmental Footprint method.
In openLCA, projects are used to compare multiple product systems You can also use parameters to benchmark various options within the same product system. The resulting report is a powerful tool to communicate the results of your comparative study.
For instance, you can compare the production of polycarbonate (PC) and polyethylene terephthalate (PET) bottles using a project in openLCA (you can access this bottle case study for free). This comparison involves evaluating two or more product systems with a comparable functional unit:
Within a project, you can also vary parameters used in your product system. This allows you to compare different versions of the same product system, which is an essential part of conducting a "Sensitivity Analysis" in a comprehensive LCA study.
After you click on "Calculate" a results tab will open showing the compared product systems, the impact assessment results
and the results contributions (flow vs impact category).
In the report tab you will find the calculated results in the template you chose beforehand. It is generated as an html file with interactive elements based on Java. The following is directly extracted from a report (Java elements can not be displayed in this manual):
This table shows the name and description of the variants as defined in the project setup. The variant names of the project setup are used for all charts and tables of the other report components.
| Variant | Description |
|---|
| PC | Poly(carbonate) bottles |
| PET | Poly(ethylene terephthalate) bottles |
The table below shows the LCIA categories of the selected LCIA method of the project. Only the LCIA categories that are selected to be displayed are shown in the report. Additionally, a user friendly name and a description for the report can be provided.
| Indicator | Unit | Description |
|---|
| Abiotic depletion | kg Sb eq | |
| Abiotic depletion (fossil fuels) | MJ | |
| Acidification | kg SO2 eq | |
| Eutrophication | kg PO4--- eq | |
| Fresh water aquatic ecotox. | kg 1,4-DB eq | |
| Global warming (GWP100a) | kg CO2 eq | |
| Human toxicity | kg 1,4-DB eq | |
| Marine aquatic ecotoxicity | kg 1,4-DB eq | |
| Ozone layer depletion (ODP) | kg CFC-11 eq | |
| Photochemical oxidation | kg C2H4 eq | |
| Terrestrial ecotoxicity | kg 1,4-DB eq | |
This table shows the LCIA results of the project variants. Each selected LCIA category is displayed in the rows and the project variants in the columns. The unit is the unit of the LCIA category as defined in the LCIA method.
| Indicator | PC | PET | Unit |
|---|
| Abiotic depletion | 8.30177e-8 | 2.05033e-9 | kg Sb eq |
| Abiotic depletion (fossil fuels) | 1.50413e+0 | 2.06903e+0 | MJ |
| Acidification | 1.54539e-3 | 9.83064e-4 | kg SO2 eq |
| Eutrophication | 1.78441e-4 | 6.37300e-5 | kg PO4--- eq |
| Fresh water aquatic ecotox. | 1.42203e-3 | 2.71658e-4 | kg 1,4-DB eq |
| Global warming (GWP100a) | 4.90240e-1 | 2.10820e-1 | kg CO2 eq |
| Human toxicity | 6.15706e-3 | 1.58586e-2 | kg 1,4-DB eq |
| Marine aquatic ecotoxicity | 1.89337e+1 | 1.60211e+1 | kg 1,4-DB eq |
| Ozone layer depletion (ODP) | 1.43767e-11 | 8.93323e-12 | kg CFC-11 eq |
| Photochemical oxidation | 1.05529e-4 | 6.36538e-5 | kg C2H4 eq |
| Terrestrial ecotoxicity | 1.61762e-3 | 4.97121e-5 | kg 1,4-DB eq |
The following chart shows the single results of each project variant for the selected indicator. You can change the selection and the chart is dynamically updated (not in the manual but in the software itself).
GWP single indicator PC vs. PET
This chart shows the contributions of the selected processes in the project setup to the variant results of the selected LCIA category. As for the single indicator results, you can change the selection and the chart is dynamically updated.
GWP process contributions PC vs. PET
The following chart shows the relative indicator results of the respective project variants. For each indicator, the maximum result is set to 100% and the results of the other variants are displayed in relation to this result.
All impact chosen impact categories for PC vs. PET
You can export a report in HTML format by clicking on the "Export report" icon located above the navigation panel. This option is available when the results window is open in the editor.
Exporting a report in HTML format
The program will prompt you to locate the folder where you want to export the HTML file. Once it is saved, you can open the HTML file with a browser (Internet Explorer, Mircosoft Edge, Safari Google Chrome, Mozilla Firefox etc.) to view the report.
Waste represents any substance or object that that needs to be dispose of, like by-products with no market value, and it can be generated at any stage of a product's life cycle. In openLCA are represented by a specific "Flow" type.
- Material flow logic approach
- Opposite direction approach
This approach aligns with the "actual" direction (i.e. material flow direction) of what is being modelled and was introduced with openLCA 1.7. Waste flows are generated as outputs of waste generating processes. In waste treatment processes they serve as the quantitative reference, and can be found on the input side.
Model graph displaying the material flow logic
- Right-click "Processes" → "New process" → "Create a waste treatment process".
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- Choose a (previously created) waste flow as your quantitative reference → click "Finish". The chosen waste flow is now an input to your waste treatment process.
Creation of a waste treatment process, material flow logic
Waste producing process following the material flow logic
Waste treatment process following the material flow logic
Note: If waste are consumed by a process, system expansion can be applied by checking the box "Avoided waste", as the waste consumed does not need waste treatment elsewhere. A process providing the benefit of using waste as an input can be credited with the avoided impact of having to treat that waste elsewhere.
Waste input flow is marked as avoided waste
The opposite direction approach works the other way around, and makes it possible to model waste treatment without the use of waste flows, but using normal process flows instead. This was the only option up until openLCA 1.7. It is still worth to mention, especially if you're working with older databases that may not include waste flows. As waste is the quantitative reference of a waste treatment process, but a quantitative reference cannot be an input to a process (since it is, essentially, the main product/output of a process), waste treatment is seen as a service necessary to provide to waste generating processes. The waste then appears as a negative output (an input) of the waste treatment process, and analogously as a negative input (an output) of the waste generating process.
Model graph displaying the opposite direction approach
- Add the waste (type: product) flow as a negative output of a waste treatment process.
- Add the waste (type: product) flow as a negative input to the waste producing process considered.
Creation of a waste treatment process, opposite direction approach
Waste treatment process following the opposite direction approach
The reason there are two different approaches is because different databases manages waste in different ways, i.e. waste flows are not present in all databases.
When a process involves several products, you have to assign how much of the impact each product is responsible for. Typical examples of such processes are co-generation of heat and power (multi-output) or a landfill (multi-input). These allocation problems can be dealt with using two different strategies; partitioning or system expansion.
There are three allocation by partitioning methods in openLCA:
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Physical allocation: partitioning based on the physical relationships between the products in terms of, for example, mass.
-
Causal allocation: partitioning based on assumptions or former research on the relative impact of different products.
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Economic allocation: partitioning based on the economic (cost or revenue) relationships between products. Consequently, an economic property in terms of cost/revenue has to be added for this to be applicable.
Moreover, we also provide the following technical solutions:
-
As defined in processes: this option will perform allocation according to the method used in each individual process along the supply chain.
-
None: if none is selected, no allocation will be applied, even for multifunctional processes.
Below is an example illustrating how the three different methods are applied in openLCA. In this example, 1 kg of wood and 0.3 kg of bark are produced from 1 kg of saw log (measured as solid wood under bark).
Inputs and Outputs for our example, note that economic properties have been added
The allocation factors for physical, causal and economic allocation can be viewed/altered in the "Allocation" tab of a process. Select the "Calculate factors" button and the software will automatically calculate the values for the three allocation methods.
The "Allocation" tab with the "Calculate factors" button
Calculate factors
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The physical allocation factors are calculated based on the ratio between the products (wood and bark) physical unit. Since the output of wood and bark is 1 kg and 0.3 kg respectively, the allocation factors become 0.77 and 0.23.
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For causal allocation an assumed ratio can be inserted. In this example, we assume that the wood is responsible for 60% of the impacts, whereas bark is responsible for 40%.
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In the case of economic allocation, we assume a revenue of 1$/kg for wood and 0.4$/kg for bark.
Calculated allocation factors. Causal allocation has to be inserted manually, else it will by default get the physical allocation factors.
Note: For allocation to work, the main product and the by-products need to have the same flow property.
Note: When a currency is unavailable, a new currency can be created under "Currencies" under the "Background data" in the Navigation plane. A conversion factor can be added according to whatever reference currency is set.
Be reminded that also recycling processes are multi-output processes as they treat waste and produce recycled material hence they require allocation. It is necessary to use allocation to distribute the impacts according to the linked process. A short example on how to model recycling in openLCA is displayed below:
The model graph for a recycling scenario
As the recycling process is a multi-output process allocation is needed! Here, physical allocation was applied.
Applying system expansion means that the process you are modeling is credited with the impact that is avoided by supplying the by-product. For example: if a process produces electricity and has heat as a by-product, it can be credited with the load that would appear if this heat was supplied from elsewhere. In openLCA, this can be performed by checking the box of "Avoided product" for the by-product.
Avoided product check box highlighted in the Inputs/Outputs tab
It is important that a process providing the avoided product flow exists. This provider then occurs in the "Model graph" when creating the "Product system", but as a supplier of the output side of our example process.
The model graph where heat is accounted for as avoided and has a respective provider besides it is an output of the process
Note that the flow which is avoided is displayed in the process but also in the product system italic. In complex models this can help you to differentiate between common flows and avoided flows.
Parameters can be used on the process, Impact assessment method, product system, project and database levels. Parameters display variables instead of concrete values used in the inputs or outputs. They can be defined as simple values, formulas or complex functions. Parameters can overwrite each other (e.g. the value set for a parameter in a process can be overwritten on the product system/project levels).
In practice, parameters facilitate sensitivity analyses to estimate how much the modification of any certain aspect of the model will impact the outcome of a study. Parameters are also useful when working with preliminary data that is subject to change or for the creation of different versions of the same system while changing certain input/output values.
Adding parameters in openLCA
In openLCA you can find three types of parameters:
- "Global" parameters can be found and are valid on all levels.
- "Input" parameters are parameters that are only valid for the process/LCIA method/Product system in which they are saved.
- ""Dependent" parameters are parameters that include input or global parameters in their formula. The figure below illustrates the view on openLCA for an example.
New! Global, input and dependent parameters can be created within a process or impact assessment method. These are then also available in product systems and projects in which the process or impact assessment method is used. It is not possible to create a new parameter on the product system or project level.
Global, Input and Dependent parameters (reload button for global parameters and add parameter button highlighted)
To create a Global parameter:
- Right-click on "Global parameters" in the "Indicators and Parameters" section in the Navigation panel.
- select "New parameter".
- Enter the name, description (optional), type (input or dependent parameter) and amount, then click on "Finish".
Creation of a global parameter
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After creating a global parameter, a general information window will open up in the Editor, and you can add tags and uncertainty (new!).
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To load in a process the global parameter you’ve created, select the "reload" button in the "Global parameters" section in the "Parameters" tab in a process or impact assessment method.
Global parameter - general information
- The global parameters can also be viewed and edited by clicking on "Parameters" under "Database" → "Content". This opens up the window below which as a (new!) feature allows editing of uncertainty by double-clicking in the "Uncertainty cell".
View and edit Parameters under Database → Content
To create an Input and Dependent parameter:
- Open the "Parameters" tab of an open process.
- Select the "+" at the top right-hand corner of the input/dependent parameters section.
- Assign a name, value, uncertainty (for an input parameter) and description.
- In case of a dependent parameter, a formula can be used to link it to the parameters it is dependent on. To write a correct formula, you can check the accepted constants, operators and functions in this chapter.
Note: An input/dependent parameter can be converted into a global parameter by right clicking on it and selecting "convert to global parameter" (new!).
Conversion of an input/dependent parameter into a global parameter
The use of parameters within a database can be checked via the "usage view" feature (right-click on a parameter and select "usage").
Note: Use the formula interpreter ("Tools" section in "Running openLCA for the first time") to check the functions you want to include in dependent parameters.
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When you edit a parameter name or value, it will now be automatically updated throughout the database, e.g. if the parameter is used in a formula of a dependent parameter, it will automatically change.
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Parameter sets: create some parameters, assign values meant for different scenarios and then save those scenarios and choose them within the same product system. An example is provided in the parameter section of the section Product systems.
If the same parameter has different values at different levels, the system's hierarchy determines which parameter value takes precedence in calculations. The parameter values at the highest hierarchy (+) overwrite the value at the lower level (-).
An illustration of the parameter hierarchy can be seen below.
For example, if a process has the same name as a global parameter 'x', then within that process, the parameter will have the process parameter value. While in another process if 'x' is used, it will have the value of the global parameter.
Hierarchy of parameters in openLCA
Compared to the previous version of openLCA, in openLCA 2 it is now possible to add so called "parameter sets", that allow the user to easily switch between parameter scenarios. When you create parameter sets, a new input field is added to the calculation properties popup window of the product system. This field then allows you to select which specific parameter set should be used for the calculations.
Product system - Calculation properties - New parameter set
In this example, we show the use of parameters and parameter sets to simulate various scenarios. The process Battery pack does include two types of electricity sources and two types of transportation. The parameters "transport_type" and "electricity_source" are both set to 1, which means the transport by truck and the electricity from renewable sources will be used to calculate the Battery pack impacts (see "Amount" column 1-parameter).
Product system - Parameter use
However, in the "Parameters" tab in the Battery Pack product system, you can switch between the different transport and electricity types by creating parameter sets. See the example given in the following figure.
Product system - Choosing a parameter set
in "Background data" you can find all the elements that users typically don't engage with often, like units, sources, locations and so on. You can freely explore this section on your active database.
Background information in a database
Locations can be regions, countries, or any other point on a map. They are important for localizing the supply chain and for calculating regional impacts.
Here an example of how locations are shown in openLCA when you click on them.
Example of how locations are shown in openLCA
This section addresses advanced aspects of openLCA and requires a solid understanding of life cycle assessment principles, impact assessment methodologies, and the functionality of the software itself.
The follow topics will be covered:
Take a look at our interactive forum ask.openLCA where you will find the latest user questions and our answers.
With openLCA you can perform regionalized impact assessment, accounting for specific conditions and characteristics of the location where the processes occur. With parameters, you can define regional characteristics affecting the impacts. Regional characteristics and information about geographic locations are contained in GeoJSON files that can be imported into openLCA
Note: regionalized calculation is an advanced form of impact calculation. It is more resource consuming that a normal impact calculation and it is needed to be handled carefully. We advise to allocate enough memory for the calculations (check "File" section of chapter "Running openLCA for the first time"), to perform it using a regionalized method (that uses locations as entities), and to check that the locations of processes are the intended ones along the whole supply chain (check section "Assign locations to processes and exchanges" below for more details).
At the moment, we offer two methods that are regionalized using locations as entities: EF 3.1 (adapted) available in openLCA method package from v2.4.0 upward, and LC-Impact available in Nexus as standalone (compatible with the same databases as our method pack). EF 3.1 (adapted) is at the moment in "hybrid" format, meaning that are characterixed both flows regionalized in the
"old-way" (therefore with the location specified in the name) and also with locations as entities. LC-Impact, instead, is regionalized in the "new-way" only (you'll see generic flows with the location specified in the location field and therefore a specific CF). For LC-Impact we provide also regionalization setups in json format, where the flow-binding has already been set.
Nonetheless, in this chapter you will learn how to bind flows yourself and to calculate characterization factors for specific locations, which works both for methods already regionalized and method that are not yet updated, but which provide geographic information for their impact factors.
A regionalized LCA needs to understand locations. In openLCA 2, available locations in a database are shown in the navigation tab under Database → Background data → Locations.
Available locations in a database
Opening one, you will see geographic data, including latitude, longitude and country code (e.g. ES for Spain), and the covered area defined by GeoJSON. It is also possible to modify the coordinates by using the text editor that can be opened by clicking on the pencil icon in the "Geographic data" section.
General geographic data - Example: Spain
Locations can be also imported in the active database, for instance from a GIS software, as GeoJSON files File → Import → other → geometries from GeoJSON.
Import of locations into active database
Alternatively, locations can be also drawn by users in geojson.io as polygons, lines or points.
geojson.io example
The coordinates text can then be just pasted in the text editor in openLCA, after the creation of a new location (right click on location folder → new location → add name and country code → open the text editor in the geographic data
("pencil" icon) → paste coordinate text from geojson.io).
Use of coordinates text from geojson.io example in the openLCA text editor
Data for regional characteristics are contained in GeoJSON files, which can be imported in openLCA. To regionalize an impact category, first go to "impact categories" folder and open an existing category (or create a new one). Then go to the tab "regionalized calculation" for the opened category. Here you need to import regional characteristics (e.g. population density, watershed area, characterization factors…) by clicking on "open" and selecting GeoJSON files available in your laptop (e.g. previously exported from a GIS software). Parameters are extracted during the GeoJSON file import and are available under the section "GeoJSON Parameters".
Regionalized calculation
Each imported parameter can be visualized in a map by selecting the parameter and clicking on the "world" icon in the GeoJSON Parameters section.
Visualization of parameters
Flows for which you want to calculate geo-spatial based CFs need to bound to the regional characteristics contained in GeoJSON files, so that the CFs can vary based on the selected location for exchanges and processes. In the "flow bindings" section under "regionalized calculation" in the open impact category, add the flows that you want to regionalize (use the "+" icon") and parametrize the "formula" field using the parameters extracted during the regional characteristics import and available under "GeoJSON parameters". In regionalized assessment, the parameter value derived from the GeoJSON file is used for the formula evaluation. Instead, if you apply non-regionalized LCIA or no location is available for exchanges and processes, the default CF value will be used in the calculations.
In "Formula" field, you can chose the parameter of your geoJSON that you want to use for the calculation of the CF of the flow you chose. You can treat that field as any other formula in openLCA. For instance, if you have a water flow expressed in Kg and the parameter of your geoJSON is in m3, you can se
In the "Range" field, you can view the minimum and maximum values for each parameter. The "Aggregation Type" field allows you to choose the aggregation type for the calculation of your CFs: "Weighted Average" (N.B.: area-weighted average), "Average," "Minimum," or "Maximum." The "Default Value" displays the value derived from the selected aggregation type performed for each parameter on your entire map.
Example of flow binding and parameterization
Currently, openLCA cannot store the GeoJSON parameters and flow bindings, but you can save and export your setup by clicking on "save". You can import this configuration again at any time by clicking on "open" and selecting the exported setup.
The calculated CFs instead (see below) can be saved and therefore permanently stored in the impact category of choice-
Saving geojson parameters and flow bindings
The last step to set-up the regionalized LCIA method, is to link process locations and LCIA methods spatial units. Therefore, the intersection between GeoJSON file features and process geometries (stored in "Locations") is calculated by the software, thus resulting in dedicated CFs for locations selected by the user. By clicking on the "calculate" icon in the "flow bindings" section, the user defines the locations for which CFs are to be calculated for the flows added in the "flow bindings" section.
Defining the location for which the characterization factors are calculated
The resulting CFs for the selected locations and flows are available in the tab "characterization factors" for the open impact category. A flow for each selected location and the same flow without a specific location are created and assigned with a CF depending on the location, or with the default CF value for the case of the flow without a specific location.
Example results of the tab "Characterization factors"
When running LCIA, you need to select an impact assessment method. Therefore, the regionalized impact category/ies need to be added to the method that will be used to calculate the product system impact. To create a new regionalized method, right-click on the folder "impact assessment methods" and select "new LCIA method". Then you can add the previously created impact category in the section "impact categories" in the first tab "general information".
Adding an impact category to the tab "General information"
To perform regionalized LCIA, make sure to assign a location to your processes and/or exchanges. You can do this by going to the "geography" section in the "General information" tab of a process and selecting your desired location.
Assigning locations to processes
Location can be assigned to exchanges in processes by adding them to the "Location" field for each flow in inputs and outputs.
Assining locations to exchanges
Note: The location specified for exchanges will take precedence over the location specified for the overall process, if they differ. For instance, if a process is assigned "Italy" as its location but some of its exchanges are designated with more specific regions (e.g., Sicily or a particular water basin), the impact will be calculated based on the exchange location. If no specific location is given for an exchange, the impact will then be calculated using the process location.
To run regionalized LCIA for a product system, select a regionalized impact assessment method and check the box "regionalized calculation". Click on "Finish" to start the calculations.
Calcualtion of a regionalized LCIA
Regionalized results can be analysed using different tabs, such as "impact analysis" and "locations".
Example results of a regionalized LCIA
The Monte Carlo simulation randomly varies your model’s input data using uncertainty distributions. This calculation method considers the uncertainty in the input data, resulting in multiple calculation results, each with a specific uncertainty distribution. Typically, several thousand iterations are carried out to obtain robust results.
The first step in openLCA is to add uncertainty data to all input and output flows in the processes. To add uncertainty data to flows, open a process, click in the uncertainty field and select "Edit". A pop-up wizard opens where you can choose between:
- Logarithmic normal distribution (Geometric mean, Geometric standard deviation)
- Normal distribution (Mean, Standard deviation)
- Triangle distribution (Minimum, Mode, Maximum)
- Uniform distribution (Minimum, Maximum)
Adding uncertainty to flows
Likewise, it is also possible to define uncertainty data for parameters as well as for LCIA characterisation factors.
Clicking on "Calculate" in a product system opens the pop-up wizard "Calculation properties". In this wizard you can select the calculation type Monte Carlo simulation and define the number of iterations.
Calculation properties: Monte Carlo simulation
Afterwards, the simulation editor will open. Select "Start" to begin the calculations. The calculation time required depends on the database and product system complexity, and the selected number of simulations. The results for each flow and impact category will be displayed while the simulation runs.
Starting a Monte Carlo Simulation
The results of the simulation can be exported as an Excel document. Simply click on the Excel icon on the right-hand side of the editor.
Monte Carlo Simulation results
The results of all processes and sub-product systems that are part of a product system can be displayed separately in the Monte Carlo Simulation tab. For easy navigation, individual processes can be pinned.
Pin/Unpin processes or subsystems
It is also possible to compare two processes with a Monte Carlo simulation if you create a process and the corresponding product system, where one process is subtracted from the other to avoid double counting of uncertainties.
Creation of a process subtracting one process to the other for future comparison in Monte Carlo simulation
Life Cycle Costing (LCC) aims to assess the costs of a product over its entire life cycle.
Costs are modelled in the software as associated with products, waste or
elementary flows, which are inputs and outputs of processes. They can be
positive or negative while a negative cost is regarded as an added value. In general, there is no need
for the creation of a method for the LCC calculation.
The implementation in openLCA follows the proposal of the SETAC working group, for costs, with some modifications, as follows:
- costs are modelled as properties of exchanges, i.e. of inputs and outputs of processes;
- costs can be positive or negative; negative costs are added value
- costs are displayed in the process editor, in a new column for the exchanges;
- when a product system is calculated, both costs and added value are available, in parallel to inventory and impact assessment results
Value added builds on this concept, taking value added as "negative costs", i.e. reversing the sign.
Starting point for the cost model and LCC calculation in openLCA are the costs for process data sets. In the process editor, costs can be entered for each exchange, i.e. for each input and output, of a process. Both costs and revenues can be considered:
Costs and revenues for flows in a process
Costs on the input side are costs. On the output side, for products, amounts in this column are revenues (the product is sold), while the release of elementary or waste flows might cause a cost, e.g. release of CO2 or emission of waste water with heavy metals. Therefore, any positive amount entered for a product on the output side refers to revenue, while every positive amount entered for an elementary flow reflects costs. To help distinguish both, costs are shown in purple, while revenues are shown in green.
To edit the costs, or to enter new costs, click in the cost column, and click on edit.
Entering or editing costs in the process editor
A new window will appear for specifying the currency and the amount costs. The amount is meant to be entered as absolute value, i.e. as costs for the amount of the exchange as it is entered for the exchange; for the example in the second figure, it is the costs for 0.12 kg. The costs per specified unit, e.g. per kg, are calculated automatically; they are shown in the small window for entering costs which opens when clicking on edit in the cost/revenue column.
Entering or editing costs, detail window, with absolute costs (costs for the amount specified for the exchange) and costs per unit which are calculated
As shown in the figures above, costs are expressed in currencies. It is possible to switch for a cost entry between different currencies in the detailed cost window. All currencies available in a database can be found under background data, in the currencies folder. For an entire database, one currency is selected as reference, for the other currencies, an exchange rate is stored to allow recalculation of costs in another currency. The exchange rates are used for calculating the conversion factors which are applied when different currencies in the process are selected.
Changing the currency of a flow
Under background data you can find the avaiable currency or add your own
The reference currency can be changed within one currency (click on "set as reference currency?").
General information on a currency
When changing the reference currency, all open currency editors will be closed for updating the conversion factors, and the editor of the new reference currency will be opened again.
In the case of multi-output processes, consideration of the costs of by-products
depends on the choice of allocation options when setting the calculation
properties (see "Allocation"). If no option is selected the price of the
by-products is considered as revenue, while if a type of allocation is chosen
the allocation factors are applied to the exchanges and the by-product cost is
not considered. The third possibility is to select the option "as defined in
processes": As before, if a type of allocation is chosen the allocation factors
are applied to the exchanges and the by-product cost is not considered; on the
contrary, if no allocation is selected all costs are calculated excluding those
from the by-products.
In case of multi-output processes in the database it is important to know what happens to the costs of by-products during the calculation of a product system. You have different options for setting the allocation method in the calculation properties.
Choosing the allocation method in openLCA during the calculation setup. The box for "Include cost calculation" is checked!
Note: Furthermore, LCC can be performed stand-alone by selecting no method when the impact assessment is run.
Depending on this choice (and depending on what is defined in the processes itself) the following rules will be applied:
- None: All costs are considered (the price of the by-product as revenue)
- Physical, causal or economic: The allocation factors are applied to the exchanges and the price of the byproduct is not considered
- As defined in processes: The physical, causal or economic allocation is chosen as defined in the processes itself. Again, the allocation factors are applied to the exchanges and the price of the by-product is not considered
and no allocation ("none") is selected in the processes, all costs except the one from the by-product are considered
If you want to apply system expansion, i.e. one of the output products is marked as "avoided product", the calculation is as follows:
When no allocation is selected in the calculation properties, the following formula is applied:
- Added value = Price Reference_Product – Price elementary flows/inputs – Price ByProduct – Added value of avoided supply chain
When allocation is selected (e.g. "As defined in processes"), the following formula is used:
- Added value = Price Reference_Product +Allocation_factor*(– Price elementary flows/inputs – Price ByProduct – Added value of avoided supply chain)
As you can define an economic flow property and hold an cost/revenue entry in the process, it is assumed that the process-specific information is more precise and the following rule is applied:
When economic allocation is selected and all output products have an economic value (revenue) defined in the process editor, those values will be taken. However, in the case that not all output products have a revenue defined, then the economic flow properties will be used for the calculation (if there are any).
Another important issue is the consideration of market variability through
uncertainty models. OpenLCA presents a column to assign an uncertainty to the input
and output flows of a process, but not to the price directly. This can be solved
by making the price a Parameter and assigning uncertainty
directly to it.
Ecoinvent database v. 3.3 in openLCA format provides prices for all products except for waste materials and their disposal. Otherwise, prices can be inserted manually in the input/output section for each process.
Several currencies are available in the database and for an entire database, one
currency can be selected as a reference for all the others.
The software allows to model different prices for the same material referred to
different processes or countries, as the price per reference unit associated with
the material is open and can be changed in the processes of the product system.
In this way, there is no need for the creation of the same material with a
different name and price associated.
As an example, a small case study will be presented in the following. The case study is taken from Moreau and Weidema (2015), who in turn refers to a publication by Heijungs and colleagues (Heijungs et al. 2013), and was rebuilt in openLCA.
The case study is a about the life cycle of a wooden chair, the functional unit defined as sitting on the chair for ten years. Overall, the chair is assumed to have a life time of 2 years, which is quite short. The simplified life cycle consists of few processes only:
- Production of wood
- Production of electricity
- Production of the chair
- Usage of the chair
- Disposal of the broken chair
Costs and material exchanges between these processes are shown in Table 1. Since the functional unit is 10 years of sitting, 5 chairs are required.
Chair case study: Processes, physical exchanges, costs and value added (Moreau and Weidema 2015, modified)
| Phase |
Product |
Amount |
Costs per unit* |
Costs** |
Value added |
| Production of electricity |
electricity |
1 MJ |
5 €/MJ |
5 € |
5 € |
| Production of wood |
wood |
1 kg |
1 €/kg |
1 € |
1 € |
| Production of chair |
electricity |
2 MJ |
5 €/MJ |
-10 € |
10 € |
| wood |
-5 kg |
1 €/kg |
-5 € |
| chair |
1 piece |
25 €/piece |
25 € |
| Use of chair |
chair |
5 pieces |
25 €/piece |
-125 € |
-135 €* |
| broken chair |
5 pieces |
2 €/piece |
-10 € |
| sitting |
10 years |
0 €/year* |
0 €* |
| Disposal of broken chair |
broken chair |
1 piece |
-2 €/piece |
2 € |
2 € |
*in Moreau and Weidema 2015: "price"; **in Moreau and Weidema 2015: "monetary amount"
In openLCA, the processes have been created, and a product system has been built where these processes exchange their products. Note that the disposal (end of life) of the chair is modelled as provided service to the use of the chair, following the typical ecoinvent (and SimaPro e.g.) modelling of end of life treatment.
The created product system in the model graph in openLCA
One example for a process with costs is already shown in first figure of this page: The production of the chair.
When the product system is calculated, several summaries of results for costs and added value are available. For example, in the process contributions tab, a new section "costs/added values" is available, which shows the contribution of different processes to the final cost and added value result. It is possible to switch between costs and value added; costs are value added multiplied by -1, i.e. costs for input products "purchased" for one process, minus price of the generated products.
Value added and net-costs in the process contributions tab
For the production of the chair, for example, net costs are (5 + 10) € - 25 € = -10€; for 5 chairs required in the product system, the amount is -50 €.
In the contributi0n tree, value added and life cycle costs are available as new section, in addition to LCIA categories and elementary flows.
openLCA offers a detailed document on how to conduct LCC studies in openLCA free here. The database with the case study is available for download here
Data quality is a critical aspect of life cycle assessment (LCA) studies, and it is addressed in ISO 14040 and ISO 14044 standards. openLCA offers a broad support for entering, managing, and calculating data quality in LCA models. Before we start, let’s remind us that in ISO 14040, data quality is defined as fitness for purpose.
Below, we describe how to work with data quality in openLCA.
First you need do define a data quality flow schema. If you generate a database with complete reference data, we provide you with two data quality systems. You can choose one of them in the "General information" tab, see "Process tab content":
Available data quality systems in an database with complete reference data in openLCA
You can also create your own data quality system or modify existing quality systems according to your own criteria. In openLCA, it is assumed that all data quality systems follow a pedigree matrix "style", i.e. there are data quality indicators that are evaluated in classes, from good to bad. These pedigree matrices can be defined from scratch, but openLCA contains some predefined data quality systems already.
Data quality system according to the ILCD data quality system requirements
To create a new data quality system, right-click on the "Data Quality Systems" directory and select "New data quality system". Then you can add indicators, scores and uncertainties.
Step 1: Creating a new data quality system
Step 2: Setup a new data quality system
Now you can select a data quality system for the process, flows and social aspects.
- Data quality information for processes must be defined in the "Data quality" section in the "General information" tab of a process window.
Process window tab - general information, data quality
- On the other hand, data quality information for flows and social assessments need to be selected under data quality columns in "Input/Output" tab or in "Social aspects" tab, see "Process tab content".
Process window tab - Inputs/Outputs, Data quality for flows
Data quality system can be selected among the systems available in the "Data
quality systems" directory in the "Indicators and parameters" section of the
active database.
Data quality systems directory in an active database
You can access existing data quality system in the folder "Data quality system" in the navigation panel. You can use for example the ecoinvent data quality system improved by dr. Andreas Ciroth (click here to read the complete report) When you open a data quality system in the Editor, you’ll see a "General information" tab. This tab displays scores for various indicators and provides options to assign uncertainty values to these indicators, as illustrated below.
Data quality systems, indicators and scores
To access the data quality during a calculation, check the box "Assess data quality" when setting the calculation properties.
Checking the box for including a data quality assessment
Then, click "Next" and the "Data quality properties" window will open, allowing you to access the details on the data quality assessment.
Setup for the data quality assessment
You can choose the aggregation type, a rounding method, and how to handle exchanges that lack data quality values. Then, click on the "Finish" button to start the calculation including the data quality assessment.
When the calculations are done, the results window will open in the Editor. You will notice that the data quality of the inventory analysis is now shown in the inventory analysis tab with color-coded numbers.
Inventory analysis - data quality information
The abbreviations for the columns are Reliability, Completeness, Temporal correlation, Geographical correlation, Further technical correlation as defined in your data quality scheme, see "Processes".
In a similar fashion, the data quality for the impact analysis tab is displayed after the calculation was performed.
Impact Analysis - data quality
openLCA can also be used to conduct social lifecycle assessments (SLCA) for any product or project. SLCA is a part of a sustainability assessment that focuses on the social impacts throughout a product's lifecycle. Guidelines for carrying out SLCA were developed (and were last updated in 2020) by the United Nations Environment Programme (UNEP) and can be freely accessed on their website.
Similar to conventional environmental LCA, there are background databases used for SLCA. In openLCA, PSILCA and SHDB are examples of social databases that can be used. You can also integrate SOCA, which is an add-on for ecoinvent LCI databases to carry out SLCA. Social LCA databases are available on openLCA Nexus, under the Database section.' This section will display content only if processes have social-related information.
In an active social database, you can find the "Social Indicators" in the "Indicators and parameters" directory.
Social indicators in "Indicators and parameters" directory
To learn more about any social indicator, you can double-click on it. In the General information tab, additional information about the unit of measurement, evaluation schema and activity variable are displayed.
General Information of a Social Indicator
Information regarding the social indicator according to each process can be viewed in the "Social Aspects" tab.Information on the raw values, risk level (evaluated according to the amount of the "raw value"), activity variable, data quality, comment and source can all be displayed. The risk-assessed indicators are characterised by the activity variable. For instance, for the time being, all indicators use working hours as an activity variable. To learn more about this and about each social indicator, it is recommended to visit the PSILICA manual which is available on the nexus website.
Process, social aspect tab
This section summarises different ways to produce impact assessment results using EPD format. There are three different methods:
It is possible to simply copy data from Excel into a process in openLCA, as long as the Excel table have the same column structure and column headings of the process inputs/outputs table in openLCA. See below.
Expanding the memory on macOS
openLCA Nexus homepage search function
Downloading a database from openLCA
Process representing the production of an oat milk pack, with its input and output
Life cycle model of an oat milk pack, with all its interconnected processes
Life cycle model of a cow milk pack, with all it interconnected processes
Calculation results window
Relative impact results of one pack of oat milk vs one pack of cow milk, obtaind using EF Method
openLCA Welcome page
openLCA toolbar
Placing tabs underneath or next to each other
Conversion factors are given in the "Formula" column
Modeling and validation tab
Result dragged in a product system
Calculating a product system
"Characterization factors" tab
Analysis - Contribution tree tab
Analysis - Contribution tree tab, cost category
Project setup, Calculation setup
Project setup, Variants
Project setup, Parameters
Created and saved processes for an EPD
"General information" tab of a process
"General information" tab of product system
Selection of Impact Assessment Methods in the calculation of a product system
"General information" tab of a result
Creating a new EPD
"Modules" section in an EPD
EPD example
Creation of the result example
Adding results to an impact category
The finished results
Linking the impacts with an inventory
