Evaluating Load Coincidence and Distribution Grid Impacts of Residential EV Charging

Residential electric vehicle (EV) charging has the potential to alter long-held assumptions on load characteristics impacting distribution grid planning, operations, and design standards. Indirect managed charging strategies like time-of-use (TOU) rates can provide load shifting and thus alleviate or exacerbate grid impacts. This study presents findings on how a TOU as-soon-as-possible (TOU-ASAP) strategy increases adverse grid impacts relative to uncontrolled charging by incentivizing higher coincident loading, while TOU as-late-as-possible (TOU-ALAP) or TOU-Random reduces adverse grid impacts relative to uncontrolled charging. These findings offer key value proposition for utilities to consider as a potential least-cost grid solution under the increasing adoption of EVs in residential sector. Furthermore, this paper highlights the need for field-practical smart charge management algorithms developed using realistic grid data.