Electricity prices have gone up significantly during the last decade, and in some countries, the electricity price is very volatile. There exist a number of policies and regulations to control the electricity market and to stimulate energy efficiency, but these are often not very transparent. Furthermore, indicators for energy efficiency can be misleading or difficult to measure. Although there are a number of approaches to modelling and simulation of energy consumption and energy optimisation, these approaches have some drawbacks such as prohibitive computing times, difficulties to address dynamic situations, and the lack of a holistic view on the manufacturing system. Other problems include the limited availability of data at the appropriate level of aggregation; sometimes the level is too low, in other cases too high. However, recently promising attempts have been made to use Discrete Event Simulation for energy modelling and production planning. It is believed that this, in combination with other ICT tools such as multi-objective optimisation, offers a promising way forward beyond current state of the art.