Renewable energies thus far have not become a part of a grid restoration process. By building small island grids after a blackout, renewable energies can be integrated into the grid restoration process. Bioenergy-based power plants have some importance for the supply of such island grids because of their high degree of reliability and controllability. Modern bioenergy plants have electrical loads within a specific kW range, which can be partially used in demand-side management. A concept for the control structure of off-grid energy systems with a demand-side management using a microgrid of a farm supplied by a biogas plant as an example is presented. For the integrability of electrical loads of the biogas plant into the energy management system of the microgrid, an off-grid control procedure has been designed.