Financial Viability of Hybrid AC-DC Power System for Buildings with EV and DC Loads

The increasing prevalence of DC-powered loads and renewable energy sources necessitates a shift in building power distribution strategies. Conventional AC-dominant systems cause significant conversion losses, resulting in higher losses and operational costs. This study explores the technoeconomic feasibility of Hybrid DC-AC Power Systems with Vehicle-to-Building (V2B) integration in DC-dominant buildings, where DC loads form a substantial portion of the total energy demand. The proposed system prioritises direct DC utilisation from photovoltaic (PV) generation, with excess energy stored in stationary batteries and electric vehicles (EVs). AC power, sourced from the grid, is used only for AC loads and as a rectified backup for DC loads when storage is insufficient. This approach minimises energy conversion losses and reduces reliance on inverters, improving cost efficiency. A detailed techno-economic analysis evaluates cost savings, return on investment (ROI), and payback periods for different DCdominant building types, including data centres, office buildings, and solar-powered residential buildings. The results indicate that data centres and office buildings exhibit the highest financial viability, with ROI exceeding 180% and payback periods of less than 3 years due to their high proportion of DCpowered loads. The analysis also demonstrates that prioritising DC distribution reduces conversion losses by up to 15%, leading to significant operational savings. The study highlights the growing relevance of DC-first power distribution in modern energy infrastructures and provides financial insights to support the transition to Hybrid DC-AC systems with V2B integration.