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Evaluation of diurnal thermal energy storage combined with cogeneration systems

Technical Report ·
DOI:https://doi.org/10.2172/6960548· OSTI ID:6960548

This report describes the results of an evaluation of thermal energy storage (TES) integrated with simple gas turbine cogeneration systems. The TES system captures and stores thermal energy from the gas turbine exhaust for immediate or future generation of process heat. 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 the following two significant advantages: (1) Electric power can be generated on demand, irrespective of the process heat load profile, thus increasing the value of the power produced; (2) 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. The study evaluated the cost of power produced by cogeneration and cogeneration/TES systems designed to serve a fixed process steam load. The value of the process steam was set at the levelized cost estimated for the steam from a conventional stand-alone boiler. Power costs for combustion turbine and combined-cycle power plants were also calculated for comparison. The results indicated that peak power production costs for the cogeneration/TES systems were between 25% and 40% lower than peak power costs estimated for a combustion turbine and between 15% and 35% lower than peak power costs estimated for a combined-cycle plant. The ranges reflect differences in the daily power production schedule and process steam pressure/temperature assumptions for the cases evaluated. Further cost reductions may result from optimization of current cogeneration/TES system designs and improvement in TES technology through future research and development.

Research Organization:
Pacific Northwest Lab., Richland, WA (United States)
Sponsoring Organization:
DOE; USDOE, Washington, DC (United States)
DOE Contract Number:
AC06-76RL01830
OSTI ID:
6960548
Report Number(s):
PNL-8298; ON: DE93004798
Country of Publication:
United States
Language:
English