United States aging electricity infrastructure of generation, transmission and distribution facilities was built over the course of a century and is dominated by alternating current (AC). Most of the loads around us are direct current (DC) load. Commercial buildings have more than 80% DC loads. DC has many advantages over AC. Due to the advancements in power electronics today, DC infrastructure can be implemented with all the advantages of saving energy and improved reliability of the grid. By doing measurements of cell phones we will demonstrate the advantages of DC source over AC. We expect energy saving of about 25-30% by using DC in place of AC. At Edison\u27s time there was no local source of DC electricity. Today solar panels are available and the installed PV system cost is as low as $1.50 per peak watt. Due to growth of electric vehicles and grid storage, battery cost is also decreasing every day. Tesla (an electric car manufacturer) is going to build a Giga watt battery manufacturing plant in US. The combination of PV and battery storage will transform the electricity infrastructure of the 21st century
