Socio-technical systems are systems where (groups of) humans interact with (non-trivial) technical systems; an example is the power grid. The people, the technical system and the combination might easily lead to complex behavior that is hard to predict and control over the long term. However, as illustrated by, for example, the need to transition our energy infrastructure to a more sustainable structure, it is necessary for society to "control" such systems. Igor Nikolic is a professor at the TU Delft where he uses agent-based modeling approach to try to understand, and thus help control and evolve such systems. We discuss the systems, the challenges as well as the modeling approaches.