Optimal dispatch and equipment sizing of a residential central utility plant for improving rooftop solar integration

Abstract This study develops a mixed-integer linear program for modeling the optimal equipment capacity and dispatch of a central utility plant (CUP) in a residential neighborhood and its ability to improve rooftop solar integration. The CUP equipment includes a microturbine, battery, chiller plant, and cooling storage. The CUP model is exposed to a variety of electricity rate structures to see how they influence its operation. The model finds the optimal capacity for each piece of CUP equipment, optimizing their hourly dispatch to meet neighborhood cooling and electric demand while maximizing profit. In an Austin, TX, USA base case, the neighborhood benefits economically by including the CUP, although the CUP demonstrates limited potential to integrate high penetrations of rooftop solar resources. While peak demand and reverse power flows are reduced under all tested rate structures, the CUP worsens net demand ramp rates. A time-of-use rate with no demand charge and moderate differences between off-peak and on-peak prices balances the output parameters, reducing reverse power flows by 43%, peak demand by 51%, and annual cost by 9.1% versus the “No CUP” base case while limiting net demand ramp rate increase to 84% more than the base case.