I. Introduction
SMART electrical grids are high on the agenda. They refer to the electricity network of the future, allowing an intelligent monitoring and/or controlling of electricity streams. In order to have an efficient energy demand management or demand side management whereby the energy use of different types of consumers can be adapted, the implementation of smart meters is strongly promoted by political as well as economic organizations [1]. In the debate towards a more energy efficient supply and demand in household settings, several ideas about smart meters and smart appliances come to the surface, ranging from alternative forms of billing to the implementation of washing machines that postpone the washing activity because of energy reasons.