In my experience Modelica is a good fit for sustainability engineering, as it works well across engineering disciplines. Simulation of hybrid gas/electric engines was one of Modelica's first major applications, power plants was another.

As others have noted Modelica is both more abstract and more performant than a lot of other ways of describing multiphysics systems; it got its start in out-of-the-way places, which may explain it's relative obscurity, but there's an opportunity for it to become pervasive in engineering, both in the academy and industry.