Non-negative restriction of summing constraint (UC_RHS)

[Antti-L]

By default, most variables are non-negative in TIMES (including VAR_COMNET and VAR_COMPRD). If you want to allow for negative CO2 emissions, you should define the corresponding variables free, or with sufficiently negative lower bounds. Usually defining a few VAR_COMNET variables free is sufficient (e.g. TOTCO2, GHG).  A shortcut for defining -INF as the lower bound of VAR_COMNET(r,t,c,s) in each period is to set:

   COM_BNDNET(r,'0',c,'ANNUAL','N')=-1;

In VEDA-FE, it would mean putting 0 in the Year column, and N in the LimType column in a ~TFM_INS table. Of course you can also directly set lower bounds (LO), but then you must choose some reasonable negative number (not too large in absolute value).