UC Berkeley

An increasing fraction of residential end-use loads operates on direct current (DC), allowing the direct use of DC from onsite DC sources (Photovoltaics, battery storage), thus avoiding the energy losses from converting DC power to alternating current (AC) and back to DC. Earlier research has shown that essentially all residential electricity end uses can be DC-compatible and are more efficient than their AC counterparts. Direct-DC power systems can provide energy and cost savings in the residential built environment (including net zero energy homes), in which electricity is generated, distributed, and consumed in DC. However, one of the main barriers to the adoption of DC distribution in buildings is the immaturity of the DC-ready appliance market. We conduct a comprehensive market and cost assessment of the current DC-ready appliance market for the dominant residential end-use applications. We then examine the growing market for DC appliances in off-grid applications to extract relevant product and market trends that may influence grid-connected environments. We also analyze the energy efficiency potential of DC-ready appliances taking into account power supply losses and their coincidence of usage with DC generation from PV or battery storage. Based on these analyses, we offer recommendations on the next steps towards the development of a DC-ready appliance market.