Goals and constraints of energy policy (e.g. cost minimization, environmental protection, security of energy supply, optimal domestic natural resource exploitation). Decision support methodologies and procedures for energy policy. Demand Side Management (DSM) methodology. Sectoral and cross-sectoral DSM programs. Evaluation of DSM programs - least cost and maximum profit approaches. Models to support demand side management processes. Integrated least cost planning methodology of the energy system. Decision support systems for energy management. Expert Systems for the promotion of the rationale use of energy in the end use. Methods and tools towards more energy efficient and sustainable cities.