LCI Source Information
Laszlo February 13, 2019 at 5:19 am
I was wondering if there was a way, when using etool, to access more detailed data about a given material.
A quick example: I have noticed that Galvanized steel (zinc coated) had a much greater impact for various indicators (such as eutrophication potential) than Stainless steel. I would like to understand why this is the case, but I am not sure how to investigate this through etool.
I used to use openLCA + ecoinvent a few years ago and I remember that when I was selecting a material from ecoinvent there was some explanation given about the material manufacturing process and assumptions. Is there somewhere I can access those information when I use AusLCI on eTool ?
To get back to the example of galvanised (zinc coated) steel, I have found this EPD for galvanised structural steel which has quite different outcomes (e.g 3.4 kg SO4eq for the EPD per ton as opposed to 16kg per ton for the material in the database). I know that those outcomes can vary substantially depending on the methods of calculation and assumptions taken, and that is why I would like to be able to access the material’s impact assumptions in a bit more detail.
This is a great question. The specific example you provided also gives us an opportunity to explain the pitfalls of generic data (and in some cases EPDs).
Acidification (kgCO4eq) is the result of sulphur (or other acid soluble compounds) pollution. The content of sulphur in the exhaust of different supply chains will differ dramatically. For example, the sulphur content of iron ore (key ingredient of steel) varies dramatically within the same mineral deposit so even a single source blast furnace operation will produce different acidification results depending on what parts of the mineral deposit their feed stock is coming from. Blast furnaces that source iron ore from the open market (the majority) tend to target very consistent feedstock as it is expensive to change setting within the furnace to deal with fluctuating contaminants and iron content. But even in this case, depending on the quality of steel being manufactured, the local environmental regulations (and a host of other factors) the sulphur content of the feed-stock will change significantly.
Another key ingredient to the steel making process is coking coal. This also has significant variations in sulphur content. So the combination of the Iron Ore and Coking Coal feedstock to a steel plant at any point in time will drive acidification impacts.
Manufacturing processes will also have various measures to mitigate contaminants like scrubbers.
And transport of the raw materials could also drive acidification where dirty fuels (or engines) are used.
Once you account for all these variables there’ll be significant deviations from the mean acidification potential for steel production. EPDs will pin point the impacts of a particular plant (at a particular time). Generic LCI data should be more of an average impact across a region.
Deviations in Global Warming Potential are generally lower between products (as energy requirements generally fluctuate less than contaminant levels).
So things to watch out for when trying to compare products:
- Is it a fair comparison (same transport distances?)
- Is it geographically relevant or comparable
- Is it temporally relevant or comparable (not old data, or a short window of production
EPDs are a great move for the construction sector and will hopefully drive manufacturers to source cleaner feed stocks by paying a premium, and install scrubbers and other mitigating technologies to reduce the impact of their products. As such we definitely need to be encouraging their production and use. It is important however to ensure we’re making fair comparisons and EPDs present some problems in this regard when indicators or life cycle modules are missing, or assumed transport distances are not relevant for the project we’re working on.
I don’t think this answer necessarily solves your problem however hopefully sheds some light on the complexity of LCI data.
To get more specific on what is driving the difference in the products it would be necessary to deep dive and understand the variables. If this is critical for your project we can ask the data suppliers to provide more information.
In short, eToolLCD is not designed to provide that kind of LCI detail. I would say that the tool’s focus is to provide a userfriendly interface that presents the most useful overview of the environmental impacts of your assessment to lead to environmental impact reductions.
Is anywhere wehre I can find the meaning of stages U1, U2 and D6 in and EPD?
I’m trying to add the values contained in the EPD but these don’t match the eTool names/stages.
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