He is busy in developing methods for intelligent and integrated energy systems. One of the main activities is hybrid numerical models and how to describe and use them. Using such models -sometimes called digital twins-, a formerly incomprehensible and complex energy system can be analyzed for efficiency, stability margins, optimality, and other expected features. With his team he works on industry and smart cities, transmission and distribution, security of supply and cyber security, hardware-in-the loop setups and number crunching for future and complex power systems.