Peak load management is a typical application that relies on dynamic sourcing of grid services and is characterized by instantaneous, dynamic needs that must be served on short notice. Therefore, decision support by autonomous systems is not an option but a must on a grid market. To achieve efficient resource utilization by contract customization without neutralizing its welfare effects by excessive transaction cost, customization must be automated by software agents that negotiate for several attributes of an SLA. Grid and agent technology are increasingly regarded complementary and emerge as a combined field of research.