Dispatchable loads for grid health: water preheaters as energy storage

As the power distribution grid adapts to distributed renewable generation, certain problems arise. Among these problems is that of high voltages during periods of excess production. Researchers at the California Smart Grid Center have analyzed the feasibility of a water preheater as an energy storage device, coupled with a controller which operates to engage the heater during periods of excess generation. A rapid prototype was produced to analyze operational requirements and to demonstrate system practicability. Research followed with a reference prototype which allowed component-level implementational analysis. Significant findings include the risk of radio interference in areas with dense wireless network saturation, and the need for a dynamic dead band during automatic operation.