A system-of-systems approach for integrated energy systems modeling and simulation

Abstract

Energy systems integration combines energy carriers, including electricity, with infrastructures, to maximize efficiency and minimize waste. In order to study systems at a variety of physical scales---from individual buildings to distribution systems---interconnected through these energy infrastructures, NREL is developing an Integrated Energy System Model (IESM), with an initial focus on the electricity system. Today's electricity grid is the most complex system ever built---and the future grid is likely to be even more complex because it will incorporate distributed energy resources (DERs) such as wind, solar, and various other sources of generation and energy storage. The complexity is further augmented by the possible evolution to new retail market structures that would provide incentives to owners of DERs to support the grid. The IESM can be used to understand and test the impact of new retail market structures and technologies such as DERs, demand-response equipment, and energy management systems on the system's ability to provide reliable electricity to all customers. The IESM is composed of a power flow simulator (GridLAB-D), building and appliance models including home energy management system implemented using either GAMS or Pyomo, a market layer, and is able to include hardware-in-the-loop simulation (testing appliances such as air conditioners, dishwashers, etc.). The IESM is a system-of-systems (SoS) simulator wherein the constituent systems are brought together in a virtual testbed. We will describe an SoS approach for developing a distributed simulation environment. We will elaborate on the methodology and the control mechanisms used in the co-simulation illustrated by a case study.