When conducting an LCA study, you can calculate scenarios: what is the difference in environmental impact if you change a certain aspect of the product? For example, what happens if you replace a regular battery with a rechargeable one? In this article, Marijn Kansen, LCA expert, explains more about conducting an LCA with different scenarios and how this method can calculate the exact environmental impact for any product.
"Recently, I performed an LCA study for a client using the PEF method, where we were curious about the scenarios involving different types of batteries. We compared regular batteries (AA alkaline batteries) with rechargeable batteries. Which of the two would be the more sustainable option?
Which battery is more sustainable, the rechargeable one or the regular alkaline battery?
“In an LCA report, we look at environmental impact across various categories. And in nearly all of these categories, we see that the environmental impact of rechargeable batteries is smaller than that of regular batteries.
This is because, with rechargeable batteries, you still see the use of certain raw materials, but instead of discarding or recycling them (which also consumes energy), you only need new energy to recharge the battery itself. So, you don’t lose raw materials, nor do you go through an entire production process again, which is the case with regular alkaline batteries.”
The table below shows the environmental impact across the different categories.
“For example, if we look at the impact category of climate change—arguably the most well-known environmental impact category—we see that the rechargeable battery has 76% less environmental impact than the alkaline battery.
Regular AA alkaline battery: 10.40 kg CO₂-eq
Rechargeable battery: 2.53 kg CO₂-eq
The only categories where the rechargeable battery has a greater environmental impact are Ionising Radiation, Marine Eutrophication, and Ozone Depletion. For Ozone Depletion, this is due to the use of a binding agent (tetrafluoroethylene) in the NiMH battery (the rechargeable battery I modelled), which is not present in the alkaline battery.
An LCA provides a complete and precise overview of the environmental impact of products. This allows you to make informed decisions regarding material choices or implement changes in your production process.”
And how did you calculate this LCA scenario?
"To create an LCA, we always use emission references from international databases, such as EcoInvent. The EcoInvent database contains standardized data on the environmental impacts of various products, processes, and services throughout their entire lifecycle.
This includes inputs like raw materials, energy, and water consumption, as well as outputs such as emissions to air, water, and soil, and waste streams. However, these references do not exist for all products, and in such cases, you need to determine the environmental emissions yourself.
This was also the case here; there was no reference available for alkaline batteries. To still make statements about the environmental impact, you have to look for data to substantiate those statements.”
How can you still determine the environmental impact of a product in such cases?
“In that case, you need to look for alternative data. For the batteries, I modelled the environmental impact based on data from a scientific LCA article. In such articles, you can find the LCI, the Life Cycle Inventory, which provides an overview of all the inputs and outputs of the product.
Examples of inputs in a Life Cycle Inventory (LCI) include raw materials like zinc or steel and energy like electricity, while outputs could be CO₂ emissions to the air or wastewater.
However, you often need to supplement this data yourself. In this case, for example, transport and recycling were not included. But by piecing together information and consulting colleagues who have previously worked with similar products, we always manage to establish a suitable emission profile.
I compared these results with the results for the rechargeable battery, which was available in EcoInvent.
To compare the two batteries, you need to define the exact scope of the comparison. In this case, it was about the environmental impact of using 50 times the energy of a single battery. I made the comparison between using 50 new batteries—meaning purchasing 50 sets of batteries—or buying one rechargeable battery and charging it 50 times.”
(This scenario was part of an LCA study we conducted for a board game manufacturer. For that LCA study, using the game 50 times was defined as the functional unit.)
