Optimization analysis of a renewable-based multi-energy system for a tertiary building

Buildings are the largest end-use sector, followed by transport, industry, and agriculture. For this reason, decarbonising residential and non-residential buildings is crucial to reach Europe's carbon neutrality by 2050. The key elements in meeting the challenge of achieving carbon neutral buildings are: a) maximising local energy production from multiple renewable energy technologies, b) matching local demand and supply energy flows, c) reducing capital costs of technologies at building level. A two-stage stochastic model is performed to define the optimal synthesis, design and operation of an energy system under uncertainty. More in detail, decisions at synthesis and design level are taken in the first stage, while decisions at operating level are handled in the second one. The integrated system for the building environment is composed of both less mature renewable technologies (e.g., biogas-based micro combined heat and power unit, variable geometry vertical axis wind turbine, latent heat thermal storage, etc.) and more established technologies. Due to the low technology readiness level, the design optimization is performed considering the investment costs of the innovative technologies and the biogas price as uncertain parameters. The building taken as reference is the Energy Center, a tertiary building in an urban context located in Turin (Italy). Application of the proposed methodology defines whether the integration of the additional novel technologies results in cost and emission reductions. Defined the optimal design, a comparison between the actual energy system of the building and the optimal one selected by the stochastic optimization are compared. Results show that some innovative technologies are selected for the optimal design, showing cost reduction up to 35% and emission reduction up to 27%.