Ever-increasing energy consumption and growing penetration of renewable energy sources stimulate the development of new power grid models and architectures. Since the decentralization of power grids raises the unreliability of power supply, it is crucial to switch to a production-oriented consumption in order to provide the stability of the grid. In this work, we describe a multi-supplier power grid model with day-ahead time span planning. We formulate and study a set of consumer cost minimization problems under flow distribution constraints. Finally, we consider an example illustrating the applicability of this model.