Feasibility analysis of a DC distribution system for a 6 kW photovoltaic installation in Ireland

Recent developments in micro-grids have led to increased interest in DC distribution due to its high efficiency in distributing energy from renewable energy sources to DC loads. This paper seeks to analyse the performance of AC and DC systems in a relatively large-sized 6 kW PV installation to determine the level of improvement in efficiency provided by DC distribution and to identify methods for further improvement. Baseline annual data for the AC system were collected from a live installation on a national school in Inis Oirr, an island off the west coast of Ireland. The results indicate that usage of a DC distribution system has the potential to reduce system losses by up to 50% as well as the ability for an annual saving in grid energy of 5% compared to the existing AC system. Moreover, the analysis reveals that DC outperforms AC distribution more in spring and autumn, when power consumption is comparable to the system production, but there is less impact in summer, when PV production is significantly higher than demand. These findings provide insights into the benefits of future DC distribution systems in individual buildings and in larger-scale micro-grids.