Contents

• General
  • Your first LCA

General

Your first LCA

What will you do

In this tutorial we will create a simple product system and perform a calculation. We will create a database and create activities and connect them to eachother. Next, we will create a calculation setup and perform a calculation.

The system we will create will be a simplified system to create electricity from coal. The data we use should not be used for any studies, it is just educational.

Before you start

[!IMPORTANT] Make sure you have/know the following:

• Know the basics of LCA
• Know common brightway terminology
• Know how Brightway organizes data
• Have a working installation of Activity Browser
• Have a project set up

1. Create a new database

To create a product system, we first need a place in the project where to put it. For this, we use databases.

• Click the New Database... button, this will open a popup.
• In the window, fill in the name 'first lca tutorial', confirm.
• We now see the new database in the Databases table on the left.

2. Create the system

Now that we have a database, we can start creating activities, which will be stored in the database.

2.1 Creating activities

Lets create the first activity: To assess the environmental impact of generating electricity from coal, we need to model the production of electricity and coal first.

• Right-click on your new database in the Databases table and choose New activity.

• Name your new activity 'electricity production, coal', confirm.
• You now see your new activity in the Activity Details tab on the right and in the database on the left.

This tab shows all information about an activity.

Your Activity Details tab should look like below:

[!TIP] You can only edit activities when the database is not set to Read-only and the activity is set to Edit Activity. You can set these in the Databases table and in the top left of the Activity Details tab respectively. This is done to avoid accidental changes.

Every time you close an Activity Details tab, the editing state will be reset, when you open the activity again you need to re-enable editing to continue to make changes.

Your changes are saved automatically.

Now, we can fill in information in the empty activity.

• In the Products table, change the Product name to 'electricity' and Unit to 'kilowatt hour'.
• Your changes are saved automatically when you press Enter or when you click somewhere else.
• Optionally set the Location to your favourite country, the default is GLO for 'global'.

The top part of your activity should now look like this:

[!NOTE] Locations and Units in Brightway and Activity Browser are 'just' text to help you organize your activities. Locations and Units don't have an inherent meaning or relationships to each other.

2.2 Linking activities

Now that we have one activity, we need to link a biosphere flow to it.

• In the Databases table in the Project tab on the left, open the database 'biosphere3' by double-clicking on it.

[!NOTE] All databases that you have open in a project are shown as tabs underneath the Databases table.

• Search for 'carbon dioxide, fossil' in the database.
• In the Activity Details enable the (still empty) Biosphere Flows table by ticking the box.
• Drag the one of the 'carbon dioxide, fossil' biosphere flows to the Biosphere Flows table, the value of the category column does not matter right now.
• Set the Amount to 0.9 kilogram by double-clicking on the Amount field and changing the value.
  • Remember that changes are saved automatically.

[!TIP] You can resize the tables in the activity details by dragging the 'splitter' between them up or down.

2.3 Finishing your system

Of course, electricity cannot be generated from nothing, so we need to add the production of coal as a new activity to the system.

We will essentially repeat the steps in 2.1 and 2.2 with other data. If you are unsure about something specific, just read back to find the information.

• Create a new activity named 'coal mining' with as Product name 'coal' and as Unit 'kilogram'.
• Again add the 'carbon dioxide, fossil' biosphere flow to the activity, set the Amount to 0.15 kilogram.
• Now switch back to the Activity Details of the activity 'electricity production, coal'.
  • Remember, if you have closed this activity in the mean time, you need to re-enable the Edit Activty toggle.
• From the database 'first lca tutorial' add the 'coal mining' activity you just created to the Technosphere Flows table of the electricity production process.
  • Remember to show the Technosphere Flows table again before adding the flow.
• Set the Amount to 0.4 kilogram.

The Activity Details of the process 'electricity production, coal' should look like this now:

Now, the mining of coal also takes some electricity, so we need to go back to the coal mining process and also add electricity as input there

• Open the 'coal mining' activity again and add 'electricity production' to the process.
• Set the Amount to 0.01 kilowatt hour.

2.4 Inspecting your system

You have now finished creating a simple product-system for producing electricity from coal!

It is good practice to inspect if everything in developing your system went correctly. You can inspect your system in a two ways:

1. Through the Technosphere Flows and Downstream Consumers tables in Activity Details.
2. Through the Graph Explorer.

Activity tables

In addition to the input flows from the technosphere and the biosphere, you can also see the Downstream Consumers table at the bottom of the Activity Details tab, which are activities that consume the product your activity produces.

For the 'electricity production, coal' activity, you should see the flow of 0.01 kilowatt hour to 'coal mining'.

You can further explore your system from the Technosphere Flows and Downstream Consumers tables by right-clicking on a flow and choosing Open Activity, which will open the Activity Details of that activity.

[!NOTE] The Downstream Consumers table is a Read-only table, you cannot change flows from that table. If you want to change a flow, you need to open the activity (Right-click > Open activity) and change the flow.

Graph Explorer

You can also look at the supply chain network visually with the Graph Explorer. You can open the graph explorer in two ways:

1. Right-clicking on an activity in a database and choosing Open activity in Graph Explorer.
2. In the top left of the Activity Details tab by clicking the Graph Explorer logo.

The Graph Explorer will show a visual representation of your system. If you hover on the flows (arrows), you will see the amount of the flow.

Our system should look similar to the following:

3 Creating a calculation setup

Now that we created a product-system, we can calculate its environmental impact.

A calculation setup exists of at least one reference product and at least one impact category.

• On the right, open the tab LCA setup.
• Click New, name your calculation setup 'first calculation setup'.
• On the left, find your activity 'electricity production' in the database we created and drag it to the Reference flows table.
• Next, on the left, open the tab Impact Categories and search for 'GWP100' and choose one of the impact categories, for this tutorial, it does not matter which one.
• Drag it to the Impact categories table.

Your calculation setup should now look like this:

4 Running an LCA calculation

Now you are ready to calculate results.

• Click the Calculate button on the top left of the LCA Setup tab.

When Activity Browser finished the calculation, it will automatically open the LCA results tab on the right. Your results should now look like this:

Congratulations! You have successfully calculated your first LCA.

[!NOTE] The activities you see in there Reference flows table are linked to your system, if you change your system, the changes are saved automatically. Do keep in mind that you do need to re-calculate your results every time you make changes.

5 (Optional) Extending your system

The above tutorial is not completely realistic, next, we will add three optional steps:

1. Adding some detail: additional activities
2. Adding more impact categories: different ways of assessing your system
3. Adding an alternative: a different way of producing electricity

You don't need to follow all steps, but the next steps build on each other, so you need to follow them in order.

5.1 Adding detail

To add detail, we will add an additional activity to produce steel.

• Create a new activity 'steel production' and make the Product name 'steel' and as Unit 'kilogram', set the Amount to 2.
• Producing steel itself emits some carbon dioxide, but we also need some coal.
• Add a coal input of 0.5 kilogram and a carbon dioxide flow of 0.5 kilogram

If you don't recall exactly how to add these, go back to step 2.1-2.3 above.

Producing electricity does not require steel directly, but of course machines and a building would be needed. We can represent this in LCA with a very small flow of steel to other processes to represent the depreciation of the machines.

• Add a 'steel' flow of 0.001 kilogram to both 'electricity production, coal' and 'coal production'
• Now recalculate your results (step 4 above).

You have now extended your system! If you want, you can add more activities and flows to make your system more realistic.

5.2 Adding more impact categories

LCA often compares products based on different categories, not just climate change impact, we will add an additional impact category to measure water use.

First, lets add an impact category to the calculation setup

• In the impact categories and search 'water use' and add it to the calculation setup.

If you don't recall exactly how to do this, go back to step 3 above.

Even though we just added the impact category, we can't yet calculate results. This is because our system does not yet have any water flows, so the impact would be zero. We will now add the water use biosphere flow to the system and then re-calculate results.

• Search in the 'biosphere3' table for 'water'
• You will see many results, we don't want to search through all of these results, but we can manually filter the results further.
• In the column Categories, click the funnel button and write 'air'.
• Activity Browser will filter all results in the column Categories for entries that contain 'air'.
• Now you have much fewer results
• Choose the flow 'water', 'air' and add it to the activity 'electricity production, coal', set the Amount to 0.0001

Now, we can re-calculate the results

• Go to the LCA Setup tab and re-calculate the results.
• In the top of the LCA Results tab you can Choose impact category, where you can switch to the water use.
• You can now see the impact of water use on your system.

You have now added a new impact category! If you want, you can add more flows and impact categories to make your system more realistic and assess different kinds of impacts.

5.3 Adding an alternative

LCA often compares different alternatives as well, we will add an alternative way of producing electricity to compare the two.

We will add an alternative production of electricity, based on natural gas

• Create a new activity 'natural gas production' and make the Product name 'natural gas' and as Unit 'megajoule'.
• Add an input of 0.002 kilogram of 'steel'.
• Add a biosphere flow of 'methane, fossil' (choose one) of 0.01 kilogram.
• Create a new activity 'electricity production, natural gas' and make the Product name 'electricity' and as Unit 'kilowatt hour'.
• Add an input of 10 megajoule of 'natural gas' and 0.002 kilogram of 'steel'.
• Also add a biosphere flow of 'carbon dioxide, fossil' of 0.7 kilogram.

If you don't recall exactly how to add these, go back to step 2.1-2.3 above.

We now have two different ways of producing electricity, from coal and natural gas.

• Now, add the 'electricity' flow from 'electricity production, natural gas' to the calculation setup.

If you don't recall exactly how to do this, go back to step 3 above.

Finally, we can now re-calculate the results and compare these two alternatives.

• Calculate the results
• Switch to the impact category 'water use' (as you did in step 5.2)
  • You will see that there is some water impact from the natural gas-based electricity. This is because the steel we use in these activities is made with electricity from coal, which affects the impact.

You have now added a new alternative! If you want, you can add more alternatives to make assess different methods of electricity production.