For GSS Energy Use chapter 5. Excerpt: ...today’s electrical grids ...have become the focus of heated societal discussions [that] range from the analysis of large-scale blackouts to controls for renewable-energy integration and smart utilization of appliances. ... physics largely determined the early evolution of electrical power systems. Nikola Tesla’s alternating-current designs were favored over Thomas Edison’s direct current.... In the US, the evolution culminated in several major grids..., the largest being the Eastern Interconnection, with approximately 40 000 nodes connected by some 50 000 transmission lines. ... grids are changing in significant ways—incorporating, for instance, time-intermittent wind and photovoltaic power in large-scale transmission grids and in consumer-scale distribution grids. ...Because transmission-grid dynamics have been dominated by large centralized generators in the past, distribution-grid dynamics have traditionally been ignored. Grid operators can no longer afford to do that. New consumer devices—for instance, electric clothes dryers that disconnect to reduce real power consumption when the grid frequency falls below a preset threshold, and smart photovoltaic inverters that can quickly respond to local voltage deviations by injecting or consuming reactive power—will produce dynamics with the potential to significantly affect the transmission grid. ...Large-scale electrical energy storage devices will potentially simplify grid operations by relaxing the need for instantaneous power delivery. Energy storage devices are expensive, though. What’s more, new algorithms are needed to optimally place and operate them to ensure the grid’s reliability. (See http://science.energy.gov/~/media/bes/pdf/reports/files/ees_rpt_print.pdf.) .... http://www.physicstoday.org/resource/1/phtoad/v66/i5/p42_s1. Scott Backhaus and Michael Chertkov, Physics Today, May 2013 issue, page 42.
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