Where can I find the emission coefficients for the IEEE 300 Bus system?. Matpower does not present these coefficients
Apart from Ipopt – are there any other decent non-linear solvers which are open source under AMPL.
Ipopt is likely the best choice if you do not have integer (including binary) variables, and if either your problem is convex, or you are willing to accept a solution that is only known to be locally optimal.
For other kinds of nonlinear optimization, see also Bonmin and Couenne on our Open Source Solvers page. Both accept integer variables, and Couenne seeks a globally optimal solution.