Topology of a Future Energy System for the South of Sweden : A Simulation for the 2030 Scenario Based on ReNOWable Findings in South of Sweden

Sammanfattning

This thesis is founded on the ReNOWable 24/7 study, which identifies the need for increased generation to meet the projected 2030 load demand while adhering to a 100% fossil-free electricity goal. This is achieved without increasing transmission line capacity. The study’s proposed solutions include the rapid implementation of batteries, wind (onshore and offshore), solar, and e-fuel-powered gas turbines. This thesis builds upon these findings by pinpointing the appropriate locations for these energy sources within the SE3 and SE4 regions of southern Sweden. This was accomplished by first identifying existing, confirmed, and planned projects stated for operation by 2030. The remaining power plants from the ReNOWable 24/7 study were then strategically added based on the specific conditions of the Swedish grid. To achieve this, two models were utilized: the N490 model and the IEEE PES Nordic 32 (N32) voltage stability model. A more accurate representation of the southern Swedish grid was achieved by combining the strengths of both models. A MATLAB script was developed to map the accurate load representation from the N490 model and the project locations into the N32 model. A simulation was then run in the N32 model to provide insight into the current grid situation. Based on the simulations and background research, the study found that the Stockholm area is the main bottleneck in the system, requiring actions to improve long-term voltage stability, particularly in the Borgvik and Stockholm regions. It was also noted that offshore wind projects provided exceptional voltage support to Sweden’s west coast, making the area ideal for e-fuel generation facilities. The study incorporated the voltage support capabilities of Type 4 wind turbine generators, as well as the batteries, solar, and gas turbines (with their SSS clutch feature). In conclusion, the study found that the proposed energy system topology successfully provided the necessary power for southern Sweden, as confirmed by the N490 results. Additionally, the system bottleneck was identified as the Stockholm region, and the distribution of power sources across the N32 model’s buses was determined. However, it should be noted that future work is needed to better create a more accurate system representation, and as will be seen in the report, the limitations lead to the need of approximations. In addition, a full voltage long term stability is needed to be done on the whole Swedish grid, not just the south of Sweden. this is due to the affect the North part has on the South part. This is further clarified and indicated in details in the report.