Thermal Energy Storage to Minimize Cost and Improve Efficiency of a Polygeneration District Energy System in a Real-Time Electricity Market

Wesley Cole, Kody Powell, Jong Kim, Kriti Kapoor, Jose Mojica, John Hedengren, Thomas Edgar

Research output: Contribution to journalArticlepeer-review

75 Scopus Citations

Abstract

District energy systems can produce low-cost utilities for large energy networks, but can also be a resource for the electric grid by their ability to ramp production or to store thermal energy by responding to real-time market signals. In this work, dynamic optimization exploits the flexibility of thermal energy storage by determining optimal times to store and extract excess energy. This concept is applied to a polygeneration distributed energy system with combined heat and power, district heating, district cooling, and chilled water thermal energy storage. The system is a university campus responsible for meeting the energy needs of tens of thousands of people. The objective for the dynamic optimization problem is to minimize cost over a 24-h period while meeting multiple loads in real time. The paper presents a novel algorithm to solve this dynamic optimization problem with energy storage by decomposing the problem into multiple static mixed-integer nonlinear programming (MINLP) problems. Another innovative feature of this work is the study of a large, complex energy network which includes the interrelations of a wide variety of energy technologies. Results indicate that a cost savings of 16.5% is realized when the system can participate in the wholesale electricity market.

Original languageAmerican English
Pages (from-to)52-63
Number of pages12
JournalEnergy
Volume113
DOIs
StatePublished - 15 Oct 2016

Bibliographical note

Publisher Copyright:
© 2016 Elsevier Ltd

NREL Publication Number

  • NREL/JA-6A20-67717

Keywords

  • Combined heat and power
  • District energy systems
  • Dynamic optimization
  • Polygeneration
  • Thermal energy storage

Fingerprint

Dive into the research topics of 'Thermal Energy Storage to Minimize Cost and Improve Efficiency of a Polygeneration District Energy System in a Real-Time Electricity Market'. Together they form a unique fingerprint.

Cite this