Using Concentrating Solar Power to Create a Geological Thermal Energy Reservoir for Seasonal Storage and Flexible Power Plant Operation Paper No. JERT-20-1280

Prashant Sharan, Kevin Kitz, Daniel Wendt, Joshua McTigue, Guangdong Zhu

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23 Scopus Citations


We propose a hybrid renewable energy system - a geothermal energy storage system (GeoTES) with solar - to provide low-cost dispatchable power at various timescales from daily, to weekly, to seasonally. GeoTES with solar uses a concentrating solar power collector field to produce hot water that is injected into a sedimentary basin to create a synthetic geothermal resource. The stored geothermal heat can then be dispatched when required by the electrical grid. GeoTES is particularly valuable for a grid with a high penetration of non-flexible renewable technologies such as photovoltaic and wind power. In this work, a sophisticated hybrid model is developed to assess the technical and economic potential of GeoTES by combining IPSEpro, which is a power-cycle simulation tool, and SAM, an economic analysis tool by National Renewable Energy Laboratory (NREL). The analysis shows with proper initial charging period that the heat loss in storage is almost negligible and is a suitable technology for long-term energy storage. Various power-cycle options are evaluated, and the most suitable power cycle is selected for further study. Annual calculations of the GeoTES system indicate that a levelized cost of storage (LCOS) of 12.4 c/kWhe can be achieved for seasonal storage of 4000 h; this value is much lower than the existing long-term storage. The LCOS of GeoTES is insensitive to the storage duration above 8 h, unlike battery and molten-salt thermal storage systems. This result demonstrates that GeoTES can be a competitive seasonal storage technology in the future electricity market. The levelized cost of electricity of the GeoTES system is also carefully analyzed and can vary between 10.0 and 16.4 c/kWhe, depending on solar-collector prices.

Original languageAmerican English
Article number010906
Number of pages15
JournalJournal of Energy Resources Technology, Transactions of the ASME
Issue number1
StatePublished - Jan 2021

Bibliographical note

Publisher Copyright:
Copyright © 2020 by ASME.

NREL Publication Number

  • NREL/JA-5500-75636


  • Alternative energy sources
  • Concentrating solar power
  • Energy conversion/systems
  • Energy storage
  • Energy storage systems
  • Energy systems analysis
  • Geothermal
  • Renewable energy
  • Seasonal storage
  • Solar thermal


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