Due to several technical improvements the number of µCHP-plants in residential buildings, industrial buildings and office buildings has increased in the last years. To achieve an economical justifiable use of the µCHP-plant it is necessary to consume the produced electrical energy on site. If an on-site consumption is not possible the electrical energy has to be sold. Selling the electrical energy at the actual electricity market conditions in Austria reduces the economic efficiency of a µCHP-plant. The degree of self-sufficiency is the quotient of the produced electrical energy of the µCHP-plant which is used on-site, and the total electrical energy demand of the building. Therefore it is one of the aims to maximise this parameter for a better economic efficiency. Based on this assumptions the aim of this work is to analyse the possibilities for an optimisation of the degree of self-sufficiency and other essential operation parameters of a µCHP-plant. To make an analysis of different systems and operation strategies a system consisting of a µCHP-plant, a thermal storage, an auxiliary burner and an electrical storage is simulated. The reference demand profiles which are published in the VDI guideline 4655 are the basic data for this simulation. Different operation strategies and the benefits of these strategies are analysed. The impact of an electrical storage in a system with a µCHP-plant has not been extensively analysed in the past. Therefore a focus of this work is the rating of an electrical storage system in an energetic and economic sense. For economic rating the annuities of the different systems are calculated. µCHP-plants with a natural gas engine and also µCHP-plants with a biomass gasifier are analysed in this work. The analysis identifies room for improvement for the energetic and economic operation parameters with the right dimensioning of the plant and a good operation strategy. Despite these improvements, the work shows the traditional separate supply as the better way in an economic sense.