James' example shows illegal use of a year range for UC_COMNET. UC_COMNET accepts only single years (and UC_RHS does not accept any year indexes). If you want to use the UC_COMNET approach, you need to define the Period range by UC_Sets: as shown earlier in the thread:
UC_Sets:T_S: 2020,2100,0
Here, the final ",0" is an "interpolation" option, such that all periods between 2020 and 2100 are included.
Alternatively, you could set UC_Sets:T_S: empty, which means that all periods are included.
Alternatively, you could set UC_Sets:T_S: empty, and use UC_CUMCOM with an exact year range.
Alternatively (if it is a single emission commodity), you could use COM_CUMNET (with an exact year range) instead of a UC.
In all UC cases, T_EACH should normally also be defined empty: UC_Sets:T_E:
UC_Sets:T_S: 2020,2100,0
Here, the final ",0" is an "interpolation" option, such that all periods between 2020 and 2100 are included.
Alternatively, you could set UC_Sets:T_S: empty, which means that all periods are included.
Alternatively, you could set UC_Sets:T_S: empty, and use UC_CUMCOM with an exact year range.
Alternatively (if it is a single emission commodity), you could use COM_CUMNET (with an exact year range) instead of a UC.
In all UC cases, T_EACH should normally also be defined empty: UC_Sets:T_E: