I've been using vSPD-online in recent weeks. Whilst it is a useful tool and allows running of simple counter-factuals, I find that the interface is a little limited and it is also hard to automate market simulations. I understand you make all the GDX files available which allows you to "self-host" and run models yourself. However, this relies on having the propietary tool GAMS, which costs several thousand $ for a commercial license.
Anyway, is there a way to run GDX files and SPD models using an open source alternative? This would be very beneficial to industry consumers.