Local energy system - Comparing direct current (LVDC) and alternating current (LVAC)

Sammanfattning: This thesis uses a case study to compare the viability of using direct current instead of alternating current to supply power to 5 buildings in a local energy system (LES). The case study sought to show how using LVDC instead of LVAC could increase the effectiveness of solar panels (PV), batteries and interconnecting buildings into a local energy system (LES). The system studied in this thesis was designed so the buildings would share the same carrier as the LES, so the LVDC LES would have DC-based buildings. The case study found that adding batteries to an LVDC system would increase self-sufficiency less than adding them to an LVAC system, and that the LVAC system would require more power from an external grid. The case study also found that using an LVDC system increased the system's overproduction and self-sufficiency for all LVDC cases. The thesis concluded that building an LVDC system where buildings could share solar overproduction and battery power, reduced the amount of power needed from an external grid by 3,5% compared to an LVAC system with separate buildings and no batteries. The LVDC system was also 23% more self-sufficient than its LVAC counterpart.