The United States has embarked on a major transformation of its electric power infrastructure. This vast infrastructure upgrade-extending from homes and businesses to fossil-fuel-powered generating plants and wind farms, affecting nearly everyone and everything in between-is central to national efforts to increase energy efficiency, reliability, and security; to transition to renewable sources of energy; to reduce greenhouse gas emissions; and to build a sustainable economy that ensures future prosperity. These and other prospective benefits of "smart" electric power grids are being pursued across the globe.