Efeitos da Integração Óptima de Sistemas de Armazenamento de Energia na Operação da Rede de Transmissão Portuguesa

Abstract

The increasing penetration of renewables is driving the flexibility requirements in power systems higher and higher. Following the nearly unanimous agreement of states to curb greenhouse gases and abate global climate change, there is a growing urgency to further scale up the integration of clean power sources, most of which are intermittent. In particular, a large quantity of such resources, mainly wind and solar, is now connected to the Portuguese network system, which makes it somehow unique. Yet, in the coming years, the system is expected to accommodate more energy sources of these and other variable technology types. In a system experiencing such levels of dynamic changes, to ensure a standard level of service provisions in terms of security, stability and reliability, the deployment and efficient utilization of various flexibility options are certainly required. Among these is battery energy storage system, which is emerging as one of the viable and effective options of increasing the much-needed flexibility in power systems. In terms of a nameplate capacity, Portugal has a considerable amount of conventional energy storage systems - namely pumped hydro power plants. However, such conventional storage mechanisms are subject to major concerns. For instance, one issue is related to their reliability due to the fact that they are mainly dependent on weather patterns. Persistent drought and erratic weather patterns highly affect their reliability, and this has negative implications on RES integration targets and other system-wide performance. Another issue concerns with the location of such storage systems; they are constructed where there is the primary resource (i.e. water) and the topography allows for their installations. Hence, the locations of hydro storage system may not be ideal for cheap energy to be stored as long as it is needed. Given the above background and motivation, the main aim of this thesis is to assess the impact of different levels and locations of non-conventional energy storage systems (battery technologies, in particular) on the operational performance of the Portuguese transmission grid, mainly in terms flexibility and variable RES power support. Especially, the potential benefits of strategically and optimally placed energy storage systems have been investigated from the aforementioned contexts. Simulation results generally indicate that deploying battery energy storage systems close to wind-rich locations can be economically viable to enhance the security of the system. Moreover, this has immense contributions to the reductions of wind power curtailments and hence costs in the system.