Setting up scenarios on Enhanced weathering

[Aravind-Srinivasachari]

Could someone help me in getting an understanding on how enhanced weathering can be added as an additional CDR removal technology and how to specifically set-it for one region.

[jayfuhrman]

Hi @Aravind-Srinivasachari,

You can download the model version used in our development paper here:

https://zenodo.org/records/7492895.

When you build the input xml files using gcamdata, it will create a file called Weathering.xml, which contains cost parametrizations and regional supply curves for rock weathering with basalt.

This can be read in as an add-on file (after dac_ssp[n].xml).

[Aravind-Srinivasachari]

Thank you very much for this @jayfuhrman . A quick follow up question - if I want to only implement weathering as a standalone CDR technology without dac what would be needed to be done?

[jayfuhrman]

Probably the easiest would be to set CO2 removal, subsector dac shareweights all to zero in A62.subsector_shrwt.csv file. Then regenerate dac_ssp[n].xml. Currently the CO2 removal sector is housed in that file, so you will need to read it in before the weathering.xml, but the subsector shareweight zero should disable DAC while enabling weathering, which is also a subsector of CO2 removal

[Aravind-Srinivasachari]

Thanks a lot for your feedback Jay. One point - I had noticed within the xml files that one of the values in A63.globaltech_coef for trn_freight was 3.67 - which is in the unit of tonne-km/kgC. But considering the output unit of trn_freight and CO2 removal sector, shouldn't this be 3667 tonne-km/ton-C? Let me know your thoughts.