polca
vanadium pentoxide - vanadium redox batteries - land use impact is suspicious
Hi, I was looking at some results and found that vanadium pentoxide production from the vanadium redox batteries dataset is a MAJOR contributor to negative scores for land use (EF or ReCiPe impact categories), I traced this down to the EF Transformation, from dump site, slag compartment. In EF and ReCiPe, Transformation x is used as a negative value.
I'm not sure what values would be correct, but I think it's highly unlikely that the production of 1kg vanadium pentoxide would cause nearly 0.5 meter2 of land transformation (positive).
Perhaps this needs a review of that process.
Hi @marc-vdm,
Thanks for spotting this. Indeed, that seems to be an error. I integrated this LCI from a third paper that was using the original inventory, but it looks like they introduced some mistakes. I have now tried to fix them:
- The original inventory refers to 0.47 kg of (residual slag - leached slag). Not 0.47 m2 of land transformation. I have now added a -0.47 kg exchange for the market for inert waste. From the original paper’s SI:
"During this process step, an extracted slag is obtained as waste. This leached slag is considered to be inert and no waste treatment is accounted for. However, the leached slag might be more susceptible to a potential risk if the slag is piled on heaps and pollutants are leaked into soil and ground water. Further treatment of the treated slag is not considered, but possible environmental risks due to leaching of contaminants to the environment have to be considered."
Additionally:
-
There was an exchange of -0.5 kg of sodium sulfate, which I have removed. It was a by-product.
-
The original inventory stated a consumption of 0.2 MJ of electricity, not 0.2 kWh. I have applied the right unit conversion.
The relevant section is 1.3.1 and Table S14. Link to the original paper: https://pubs.acs.org/doi/suppl/10.1021/acs.est.8b02073/suppl_file/es8b02073_si_001.pdf
