Elaine Hale

Building energy model reduction for model predictive control using OpenStudio

Model-based predictive control for buildings is an active area of research. Significant effort has been placed on developing accurate and computationally efficient reduced-order models that can be implemented in predictive controllers. During a buildings design and construction process, detailed building models are often created by experienced building modelers. These models are often too complex to be directly implemented in control applications. Reducing these models to low-order models can be time-consuming and require additional skills beyond those possessed by building modelers. In this paper we demonstrate simple reduction of building models using the OpenStudio analysis framework in a script-based environment. OpenStudio is a cross-platform tool for modeling and analysis of building energy systems. A reduced-order model is created for a simple building and an economic-based model predictive controller is used to minimize summertime cooling costs in an electricity market with real-time pricing.

IGMS: An Integrated ISO-to-Appliance Scale Grid Modeling System

This paper describes the integrated grid modeling system (IGMS), a novel electric power system modeling platform for integrated transmission-distribution analysis that co-simulates off-the-shelf tools on high performance computing platforms to offer unprecedented resolution from independent system operator (ISO) markets down to appliances and other end uses. Specifically, the system simultaneously models hundreds or thousands of distribution systems in co-simulation with detailed ISO markets and automatic generator control-level reserve deployment. IGMS uses a new message passing interface-based hierarchical co-simulation framework to connect existing sub-domain models. Our initial efforts integrate open-source tools for wholesale markets, bulk ac power flow, and full-featured distribution systems including physics-based end-use and distributed generation models (many instances of GridLAB-D). The modular IGMS framework enables tool substitution and additions for multi-domain analyses. This paper describes the IGMS tool, characterizes its performance, and demonstrates the impacts of the coupled simulations for analyzing high-penetration solar photovoltaic and price responsive load scenarios.

Implications of Model Structure and Detail for Utility Planning: Scenario Case Studies Using the Resource Planning Model

NOTICE This report was prepared as an account of work sponsored by an agency of the United States government. Neither the United States government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States government or any agency thereof. formerly) deserves our special gratitude for his thought leadership and insights at the inception of the Resource Planning Model. Any remaining errors or omissions are the sole responsibility of the authors. Abstract Capacity expansion models are computational tools designed to find the least cost option for planning a system under a variety of policy, business, and operational constraints. In this report, we analyze the impacts of model configuration and detail on resource selection decisions of capacity expansion models. Our analysis focuses on the importance of model configurations— particularly those related to capacity credit, dispatch modeling, and transmission modeling—to the construction of scenario futures. Our analysis is primarily directed toward advanced tools used for utility planning and those impacts that are most relevant to decisions about future renewable capacity deployment. To serve this purpose, we develop and employ the National Renewable Energy Laboratorys Resource Planning Model to conduct a case study analysis that explores 11 capacity expansion model configuration scenarios for the Western Interconnection through 2030. While the analysis results cover the entire Western Interconnection, the model and research examine in greater detail a region within the interconnection that consists of two balancing areas—the Public Service Company of Colorado and the Western Area Power Administration Colorado/Missouri—that serve load primarily in and around the state of Colorado. We examine how model investment decisions change under different model configurations and assumptions related to renewable capacity credit, the inclusion or exclusion of operating reserves, dispatch period sampling, transmission power flow modeling, renewable spur line costs, and the ability of a planning region to import and export power. For all modeled scenarios, we …

Experiences integrating transmission and distribution simulations for DERs with the Integrated Grid Modeling System (IGMS)

This paper discusses the development of, approaches for, experiences with, and some results from a large-scale, high-performance-computer-based (HPC-based) co-simulation of electric power transmission and distribution systems using the Integrated Grid Modeling System (IGMS). IGMS was developed at the National Renewable Energy Laboratory (NREL) as a novel Independent System Operator (ISO)-to-appliance scale electric power system modeling platform that combines off-the-shelf tools to simultaneously model 100s to 1000s of distribution systems in co-simulation with detailed ISO markets, transmission power flows, and AGC-level reserve deployment. Lessons learned from the co-simulation architecture development are shared, along with a case study that explores the reactive power impacts of PV inverter voltage support on the bulk power system.

Final Technical Report: Integrated Distribution-Transmission Analysis for Very High Penetration Solar PV

Transmission and distribution simulations have historically been conducted separately, echoing their division in grid operations and planning while avoiding inherent computational challenges. Today, however, rapid growth in distributed energy resources (DERs)--including distributed generation from solar photovoltaics (DGPV)--requires understanding the unprecedented interactions between distribution and transmission. To capture these interactions, especially for high-penetration DGPV scenarios, this research project developed a first-of-its-kind, high performance computer (HPC) based, integrated transmission-distribution tool, the Integrated Grid Modeling System (IGMS). The tool was then used in initial explorations of system-wide operational interactions of high-penetration DGPV.

Time Domain Partitioning of Electricity Production Cost Simulations

Production cost models are often used for planning by simulating power system operations over long time horizons. The simulation of a day-ahead energy market can take several weeks to compute. Tractability improvements are often made through model simplifications, such as: reductions in transmission modeling detail, relaxation of commitment variable integrality, reductions in cost modeling detail, etc. One common simplification is to partition the simulation horizon so that weekly or monthly horizons can be simulated in parallel. However, horizon partitions are often executed with overlap periods of arbitrary and sometimes zero length. We calculate the time domain persistence of historical unit commitment decisions to inform time domain partitioning of production cost models. The results are implemented using PLEXOS production cost modeling software in an HPC environment to improve the computation time of simulations while maintaining solution integrity.

Considering renewables in capacity expansion models: Capturing flexibility with hourly dispatch

The Resource Planning Model co-optimizes dispatch and capacity expansion using a simplified, chronological dispatch period representation and high-resolution resource, load and infrastructure data. The computational tractability of capacity expansion models depends on model simplifications. We demonstrate the effects of various dispatch period representations on model results using the Resource Planning Model.