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Title: Thermodynamic performance and cost optimization of a novel hybrid thermal-compressed air energy storage system design

Compressed Air Energy Storage (CAES) can potentially allow renewable energy sources to meet electricity demands as reliably as coal-fired power plants. However, conventional CAES systems rely on the combustion of natural gas, require large storage volumes, and operate at high pressures, which possess inherent problems such as high costs, strict geological locations, and the production of greenhouse gas emissions. A novel and patented hybrid thermal-compressed air energy storage (HT-CAES) design is presented which allows a portion of the available energy, from the grid or renewable sources, to operate a compressor and the remainder to be converted and stored in the form of heat, through joule heating in a sensible thermal storage medium. The HT-CAES design incudes a turbocharger unit that provides supplementary mass flow rate alongside the air storage. The hybrid design and the addition of a turbocharger have the beneficial effect of mitigating the shortcomings of conventional CAES systems and its derivatives by eliminating combustion emissions and reducing storage volumes, operating pressures, and costs. Storage efficiency and cost are the two key factors, which upon integration with renewable energies would allow the sources to operate as independent forms of sustainable energy. The potential of the HT-CAES design is illustratedmore » through a thermodynamic optimization study, which outlines key variables that have a major impact on the performance and economics of the storage system. The optimization analysis quantifies the required distribution of energy between thermal and compressed air energy storage, for maximum efficiency, and for minimum cost. This study provides a roundtrip energy and exergy efficiency map of the storage system and illustrates a trade off that exists between its capital cost and performance.« less
 [1] ;  [2] ;  [2]
  1. National Renewable Energy Lab. (NREL), Golden, CO (United States)
  2. Univ. of California, Los Angeles, CA (United States)
Publication Date:
Report Number(s):
Journal ID: ISSN 2352-152X
Grant/Contract Number:
Accepted Manuscript
Journal Name:
Journal of Energy Storage
Additional Journal Information:
Journal Volume: 18; Journal Issue: C; Journal ID: ISSN 2352-152X
Research Org:
National Renewable Energy Lab. (NREL), Golden, CO (United States)
Sponsoring Org:
USDOE Office of Energy Efficiency and Renewable Energy (EERE)
Country of Publication:
United States
25 ENERGY STORAGE; air energy storage; storage efficiency; thermodynamic optimization
OSTI Identifier: