Within the framework of the European project REN+HOMES, a seven-storey demo multi-apartment building (MAB) will be built in the city centre of Innsbruck (AT) with the goal of demonstrating the possibility and challenges of achieving a positive energy balance. The MAB will be built with a very high envelope quality and MVHR (i.e. Passive House Premium certified) and with shower drain water heat recovery. A very efficient low-temperature heat emission and distribution system combined with a central groundwater heat pump for domestic hot water (DHW) production and space heating allows very low electricity demand, such that on-site PV, partly on the roof and partly on the façade can cover it. Batteries for short-term storage and a hydrogen system for seasonal storage complete the system. Another novelty of this project is that the waste heat of the hydrogen storage will be integrated into the building to cover part of the DHW, increasing the efficiency of the system. Within this work, a holistic analysis of the MAB with 7 storeys, 42 flats and a treated floor area of 2838 m2 is performed aiming at optimising the size of the hydrogen system, PV and battery storage also considering different scenarios for the electricity demand of the appliances and control strategies that allows an increase of direct PV self-consumption. The parametric study is performed by means of dynamic simulations in Matlab/Simulink and the results show that the net positive balance can be achieved, but building-level autarky could only be achieved with off-site PV.