The impact of flexible loads in increasingly renewable grids

We develop a flexible and responsive electrical load in the form of domestic refrigerators augmented with a thermal storage system, a wireless sensor network for monitoring and actuation, and a controller that enables response to external controls. Using this, we investigate the potential of such loads for two applications: price-responsive demand and supply-following. Our prototype shows that with a 13% increase in refrigerator electricity consumption, we are able to avoid electricity consumption for over six hours. We employ a methodology for creating models of electricity grids with high renewables penetration, and study the effects of deploying variable populations of flexible energy storage refrigerators in grids at variable levels of renewables penetration. Our results show that our prototype can respond to time-of-use price tariffs to reduce summer refrigeration electricity cost by up to 13% on the consumer side, while substantially reducing the capital investment on the utility side by smoothing the peak. At higher levels of renewables penetration, with 20% of refrigerators in California adopting this technology and acting as supply-following electricity loads, flexible refrigerators can shave off 5% of peak capacity needs. The approach naturally extends to similar applications in thermal management of buildings and would operate in concert with other load management efforts such as smart vehicle charging.