An inherent feature of the modernization of America’s electrical power grid is a rapidly emerging Big Data (BD) presence. The American Recovery and Reinvestment Act (ARRA) of 2009 allocated over $4 billion to deployment of new technology for grid monitoring, control and infrastructure protection.  This led to a dramatic proliferation in the use of BD across multiple operational domains such as generation, transmission and distribution, customers, services, and markets. The use of metering data to better understand customer behavior, synchrophasors (phasor measurements synchronized using GPS clock) to enhance the robustness of grid operation, and spatial-temporal correlation of weather data to improve renewable generation forecasts  are examples of BD’s pervasive impacts on smart grids. A challenging goal is to convert BD in smart grids, which is overwhelmingly abundant and yet grossly underutilized, into new knowledge that can offer major improvements in the above mentioned domains of smart grid operation, including management of almost a trillion dollars in grid infrastructure annually  and an increase in building energy efficiency by at least 20% by 2020.