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Evaluation of diurnal thermal energy storage combined with cogeneration systems. Phase 2

Technical Report ·
DOI:https://doi.org/10.2172/10178486· OSTI ID:10178486

This report describes the results of a study of thermal energy storage (TES) systems integrated with combined-cycle gas turbine cogeneration systems. Integrating thermal energy storage with conventional cogeneration equipment increases the initial cost of the combined system; but, by decoupling electric power and process heat production, the system offers two significant advantages. First, electric power can be generated on demand, irrespective of the process heat load profile, thus increasing the value of the power produced. Second, although supplementary firing could be used to serve independently varying electric and process heat loads, this approach is inefficient. Integrating TES with cogeneration can serve the two independent loads while firing all fuel in the gas turbine. An earlier study analyzed TES integrated with a simple-cycle cogeneration system. This follow-on study evaluated the cost of power produced by a combined-cycle electric power plant (CC), a combined-cycle cogeneration plant (CC/Cogen), and a combined-cycle cogeneration plant integrated with thermal energy storage (CC/TES/Cogen). Each of these three systems was designed to serve a fixed (24 hr/day) process steam load. The value of producing electricity was set at the levelized cost for a CC plant, while the value of the process steam was for a conventional stand-alone boiler. The results presented here compared the costs for CC/TES/Cogen system with those of the CC and the CC/Cogen plants. They indicate relatively poor economic prospects for integrating TES with a combined-cycle cogeneration power plant for the assumed designs. The major reason is the extremely close approach temperatures at the storage media heaters, which makes the heaters large and therefore expensive.

Research Organization:
Pacific Northwest Lab., Richland, WA (United States)
Sponsoring Organization:
USDOE, Washington, DC (United States)
DOE Contract Number:
AC06-76RL01830
OSTI ID:
10178486
Report Number(s):
PNL--8717; ON: DE93019106
Country of Publication:
United States
Language:
English