openLCA archived user forum

Hello OpenLCA forum,

I’m a new OpenLCA user and I‘m in front of a misunderstanding. Here, I think it’s a good place to overcome it.
In order to avoid increasing the complexity of this explanation, let me give you an simply example.

I would like to realize a LCA of chocolate pie composed by a pastry base and a chocolate ganache.

LCA of chocolate pie
PROCESS 1 : pastry base
flow 1 : 100g flour
flow 2 : 2 eggs
PROCESS 2 : chocolate ganache
flow 1 : 50g flour
flow 2 : 200g chocolate

I would like to obtain not only environmental impacts of chocolate pie but also that of its components (pastry base & ganache).

The “contribution tree” tab of OpenLCA give me the right information. I expected the same from the Excel export file but…
In this file :
- The tab “LCIA total” give me : chocolate pie = 2g CO2eq for climate change impact for example.
- The tab "LCIA contribution", correctly describes the contribution of each flow but does not give the impact of each process. Worse, he sum the impact of identical flow from two different processes (here is flour) making impossible to calculate "manually" the contribution of each process. So, this Excel file loses a lot of value for what I want to do.

Finally, there is a only one solution : copy-paste the “contribution tree” calculated by OpenLCA for each impact to analyze it on Excel. But, it’s longer and impossible to create an automated tool by doing that.
To make an LCA, this Excel file seems unusable. I hope I’m wrong…

Is my reasoning good?
Do I have a simple and automatic way to recover "a contribution tree" or to calculate it via Excel?


Given the recipe, I hope you never have to eat this chocolate pie one day…
Please, I'm sorry to express myself with a poor english. Thanks a lot for your help! Have a nice day.
Alexy

Hi Alexy,
welcome! Well the contribution tree shows a tree which is calculated from the network, where typically loops are responsible for a process to be used more than once. In the tree, the loops are "opened", which has as effect that a process may appear multiple times. If you are interested in the total contribution of a process to the result, you can check the process results tab, or the sankey diagram.
Hth,
Andreas

Thanks aciroth for your quick reply!
Actually, I would like to import, easily, the contribution tree data in Excel to reanalyse and make my own chart in order to create an automatic tool to analyze LCA results in Excel.
The Excel export file doest not allow to recreate the contribution tree for the reason I was developped in my previous message.
The only solution is to copy-paste the contribution tree in Excel for each impact assessment (climate change, acidification...). But, sometimes, there are a lot of impact assessment and so, the automatism that I'm looking for is lost...

Thanks again ! Have a nice day.
Alexy

Hello Alexy,

indeed. It is a problem I faced too.

It is also worth noting that copy-pasting data from the contribution tree will reproduce data in a text format.
Hence, to properly copy it on an Excel spreadsheet, you need to "special-paste" as tab-separated text information, paying attention to the decimal and thousand-separators signs your system is using (having a European system, I had to change dots for commas and remove commas as thousands-separator sign).

An export-to-Excel function from the contribution tree tab could indeed be a nice future function :-)

Best regards,
Romain

Indeed, a bulk export of the tree to excel is not available yet; I agree this would be a nice feature, although for some systems, you will get a huge output file - if someone is interested in the implementation, please let me know.

Many thanks for your reply. I wanted to ensure that this problem was not due to my misunderstanding.
It's a shame not to take advantage of this excel export file. Maybe in the future...

Hello,

I am a Mac user and cannot seem to even copy-paste the contribution tree results. I've tried both command-c and shift-c to try to highlight the output, and I can't get anything to stick. Has anyone else had this issue? Is there a way around it?

Many thanks,

Nicole

Update: I received information from another user about how to accomplish this on a Mac. Instructions below:

- Update version to 1.4.2 (or latest version)
- highlight some of the contribution tree table, even 1 cell will do
- type command-A to “select all” and then
- right click in the selected stuff and you should see a pop-up option to “Copy”

You'll also see an option to "expand all" when you see the copy option. In my experience, openLCA hangs up whenever you choose this, so I just manually expand all of the processes I want to be able to copy.

Thanks Nicole!
- if you expand all, then depending on both your product system and your computer this can indeed take long, but it should work in the end. Issue is that the tree contributions are calculated on the fly, therefore while expanding, many smaller calculations are performed.