Rough investigation: Open-source solver time and memory penalties

[Antti-L]

@VictorG: Thanks a lot for the comparison with your bigger model instance. Indeed, many TIMES models have already been in the 2–10 million range in terms of number of constraints, and the TIMES GAMS code usually still performs quite well with such larger models.  For example, I would expect your test model to be generated by GAMS in less than 2 minutes, correct?  With such larger TIMES models, I suspect that under Julia/Python the performance of the model generator might not scale up so well and the overhead could become notable, but that is something the feasibility evaluation should be able to estimate.