Benefits of Direct Current Electricity Supply for Domestic Application

Although, the use of DC in the home has a long history, AC is presently used almost exclusively in all domestic electricity supply with DC limited only to niche applications such as motorised caravans/mobile homes and other leisure craft. In recent years there has been growing interest in the use of DC in the home partly because many modern home appliances use DC voltages and most renewable energy sources generate DC power. Continued use of AC therefore seems wasteful, as the energy has to be converted using an inverter from DC to AC and then using an AC to DC converter back to DC with consequent energy losses. Elimination of this multiple stage energy conversion saves energy, and CO2 emissions. Most of the previous works undertaken to assess the feasibility of DC in the home have concluded that it is not practical for technical and cost reasons. This research re-examines the methodologies and assumptions used in previous work on DC. In contrast to previous work whose goal was to determine if DC voltage could substitute AC voltage in home applications, the primary objective of this research was to assess whether DC voltage could be used in the home avoiding any constraints imposed by how electricity is used today. A novel bottom-up approach is proposed starting with real DC loads that are found on the open market. These DC loads are apportioned to different zones, power sockets and cable spurs to determine the DC voltage peak power that directly correlates with real DC loads. Even given the constraints of voltage drops along the cables, this approach allows for the use of 4mm2 cables in the design and enables micromanagement of the loads. Previous works have suggested much bigger cable gauges.Different design implementations/scenarios are investigated from which it has been shown that low power DC voltage can be practically and economically implemented with cables of an acceptable gauge. Some of the indirect economic and socioeconomic benefits that widespread use of DC in the home provides are discussed. These include Energy Independence with Energy Security, reduced pressure to import fossil fuels, the advantages of decentralised energy generation, and the increase in the quality of life and Gross Domestic Product of developing nations. It is concluded however, that a full implementation of a DC system will only become possible within the context of Smart House Technology.