The development of Smart Grids requires supplementary ICT-architectures in order to exploit the systems full potential. However, a green field approach is not applicable for developing these architectures. The existing power distribution and transmission infrastructure stipulates numerous requirements. Thus, the field of requirements engineering as a significant part of software engineering is of high importance for the development process. In this contribution requirements engineering is investigated in the context of Smart Grids. Different approaches are introduced and applied to software and architecture development in Smart Grids. Finally, a set of requirements and according use cases for developing a Smart Grid ICT-architecture is presented. They are derived using established methodologies and specifications that discussed in this contribution.