Pumped Thermal Electricity Storage with Supercritical CO2 Cycles and Solar Heat Input: Preprint

Joshua Dominic McTigue, Ty Neises, Pau Farres-Antunez, Kevin Ellingwood, Alexander White

Research output: Contribution to conferencePaper


Pumped Thermal Electricity Storage (PTES) is an energy storage device that uses grid electricity to drive a heat pump to generate hot and cold storage reservoirs. This thermal potential is later used to power a heat engine and return electricity to the grid. In this article, a PTES variant that uses supercritical carbon dioxide (sCO2) as the working fluid is introduced. sCO2-PTES cycles have higher work ratios and power densities than the systems based on ideal gases that have been investigated to date. Furthermore, sCO2-PTES cycles may achieve higher round-trip efficiencies for a given hot storage temperature (up to 78% at 560 degrees C). The sensitivity of PTES cycles to loss factors such as isentropic efficiencies and temperature differences between the power cycle and storage fluid is investigated. A second concept whereby an sCO2-PTES cycle is integrated with concentrating solar power (CSP) is introduced. This concept 'time-shifts' the recompression of an sCO2 recompression cycle to a period of lower electricity prices and stores the heat. When solar heat is dispatched, the recompressor may be avoided as the required heat is obtained from storage, thereby leading to increased heat engine efficiencies. The net work output of this integrated system is 10-18% greater than the conventional recompression cycle. Combining PTES with a CSP power cycle is therefore shown to improve the dispatch of solar heat as well as providing electricity storage services.
Original languageAmerican English
Number of pages14
StatePublished - 2019
Event2019 Solar Power and Chemical Energy Systems Conference (SolarPACES) - Daegu, South Korea
Duration: 1 Oct 20194 Oct 2019


Conference2019 Solar Power and Chemical Energy Systems Conference (SolarPACES)
CityDaegu, South Korea

Bibliographical note

See NREL/CP-5500-80181 for paper as published in proceedings

NREL Publication Number

  • NREL/CP-5500-74753


  • concentrating
  • electricity
  • power
  • PTES
  • pumped
  • SCO2
  • solar
  • storage
  • thermal


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