Running two carbon markets in the same region - Please help!

[BmarcyB]

Hi,

I am trying to run two carbon markets in the US, where GCAM solves for the carbon price necessary to reach net zero with the inclusion of a fixed methane price (which applies to methane only). So, the two markets I want to run (concurrently) are:

Fixed methane price
Variable carbon price for everything else, subject to an emission constraint that gets the US to net zero by 2050
I have tried to accomplish this by specifying two markets in the US ("Methane" and "GHG"): one with a fixed price and one with an emission constraint. I have then used a linked policy to set the "price adjust" to 0 for all other gasses in the "Methane" policy. See attached files of this below:

linked_ghg_policy_2.txt
carbon_tax_CH4_Policy_US_Only_2.txt

Any help would be most appreciated!
Thanks!!

P.S. If this illuminates in some way, the error message upon the carbon markets kicking-in in 2025 is:
ERROR: Could not find market: USAGHG to get an ordering for.