skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Improving Hybrid Efficiency and Flexibility by Integrating Thermal Energy Storage into the Fuel Cell System

; ; ;
Publication Date:
Research Org.:
National Energy Technology Lab. (NETL), Pittsburgh, PA, and Morgantown, WV (United States). In-house Research
Sponsoring Org.:
USDOE Office of Fossil Energy (FE)
OSTI Identifier:
Report Number(s):
Resource Type:
Resource Relation:
Conference: David Tucker, Nor Farida Harun, Valentina Zaccaria, and Lawrence Shadle (2017) Improving Hybrid Efficiency and Flexibility by Integrating Thermal Energy Storage into the Fuel Cell System, World Innovation Conference and Expo, Washington, DC, May 14-17, 2017, Paper #902
Country of Publication:
United States
01 COAL, LIGNITE, AND PEAT; 03 NATURAL GAS; 08 HYDROGEN; 10 SYNTHETIC FUELS; 20 FOSSIL-FUELED POWER PLANTS; 25 ENERGY STORAGE; 42 ENGINEERING; Fuel Cells, thermal Energy Storage, Fuel Flexibility, dynamic control, process dynamics

Citation Formats

Shadle, Lawrence J., Tucker, David A., Harun, Nor F., and Zaccaria, Valentina. Improving Hybrid Efficiency and Flexibility by Integrating Thermal Energy Storage into the Fuel Cell System. United States: N. p., 2017. Web.
Shadle, Lawrence J., Tucker, David A., Harun, Nor F., & Zaccaria, Valentina. Improving Hybrid Efficiency and Flexibility by Integrating Thermal Energy Storage into the Fuel Cell System. United States.
Shadle, Lawrence J., Tucker, David A., Harun, Nor F., and Zaccaria, Valentina. 2017. "Improving Hybrid Efficiency and Flexibility by Integrating Thermal Energy Storage into the Fuel Cell System". United States. doi:.
title = {Improving Hybrid Efficiency and Flexibility by Integrating Thermal Energy Storage into the Fuel Cell System},
author = {Shadle, Lawrence J. and Tucker, David A. and Harun, Nor F. and Zaccaria, Valentina},
abstractNote = {},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = 2017,
month = 5

Other availability
Please see Document Availability for additional information on obtaining the full-text document. Library patrons may search WorldCat to identify libraries that hold this conference proceeding.

Save / Share:
  • Thermodynamic efficiency must be considered in the effective analysis of gas turbine fuel cell power generation system performance. In most numerical simulations of hybrid systems, the use of compressor maps and turbine maps are neglected. It is assumed that the design criterion generated by the system model can be met by the manufacturer of these items. These system models may use partial information from a compressor map, or a turbine map, but they fail to match all the operating conditions of both maps in a hybrid configuration. Also, to simplify the calculations that are performed by the complex hybrid systemmore » models, the effects of heat transfer and fluid dynamic drag are often decoupled. When system calculations are done in this way, the resulting calculations for system efficiency may suffer error. Hybrid system designers need a simple method to calculate the system performance directly from the maps of real compressors and real turbines that currently exist, and that would be part of a hybrid system. In this work, a simple procedure is illustrated where a coupled analysis of the various system components is performed and included as part of the system model. This analysis is done using the compressor and turbine maps of the hybrid performance project hardware at the U.S. Department of Energy, National Energy Technology Laboratory (NETL). Model parameters are tuned using experimental conditions and results are obtained. The results show the importance of aerodynamic coupling in system models, and how this coupling affects the system efficiency calculations. This coupling becomes important especially for the variable density flows that are typically found in combustors, heat exchangers and fuel cells.« less
  • This paper examines two coal-based hybrid configurations that employ separated anode and cathode streams for the capture and compression of CO2. One configuration uses a standard Brayton cycle, and the other adds heat recuperation ahead of the fuel cell. Results show that peak efficiencies near 55% are possible, regardless of cycle configuration, including the cost in terms of energy production of CO2 capture and compression. The power that is required to capture and compress the CO2 is shown to be approximately 15% of the total plant power.
  • In recent years there has been significant interest in identifying carbon capturing technologies that can be applied to fossil fuel power generation plants.CO 2 capture technologies seek to reduce the amount of CO 2 that would normally be emitted into the atmosphere from the daily operation of these plants. In terms of system efficiency and operating costs, this carbon capture is expensive. Further, the additional equipment that would be used to capture CO 2 emissions greatly adds to the complexity of the system. There has also been significant interest in coal based gas turbine fuel cell hybrid power plants. Amore » hybrid power plant can have much greater system efficiency than a normal gas turbine power plant because the heat that is normally unused in a standalone solid oxide fuel cell (SOFC) is recovered and used to drive a power producing turbine. It is thought that the increased system efficiency of the hybrid system might compensate for the increased expense of performing carbon capture. In order to provide some analytical insight on this tradeoff we present a 100 MW class coal fired gas turbine SOFC hybrid power generation system. The hybrid system operates at a pressure ratio of 6, and uses heat recuperation and cathode air recirculation to control the SOFC inlet temperature and the temperature change across the SOFC. A carbon capture scheme is added to this system in order to calculate the relative energy cost in terms of system efficiency due to CO 2 compression. The carbon capture is performed by burning the unused fuel from the SOFC in an isolated anode stream using pure O 2 injection. The resulting heat that is generated from this process is then used to drive a secondary turbine that is placed in the anode exhaust stream where more work is extracted. With an isolated anode stream, the products of combustion from this secondary combustion process are mostly water and carbon dioxide. The water by-product is then condensed out of the stream leaving a relatively high concentration of CO 2. This is then compressed, and removed from the system. In this study we present power plant efficiency calculations for the performance of the hybrid system with the carbon capturing loop. Our results show the effects on system performance that result from a changing fuel utilization factor.« less
  • United Technologies Corporation has been conducting a development program sponsored by Lewis Research Center of NASA directed toward advancing the state of the art of the alkaline fuel cell. The goal of the program is the development of an extended endurance, high-performance, high-efficiency fuel cell for use in a multi-hundred kilowatt regenerative fuel cell. This technology advancement program has identified a low-weight design and cell components with increased performance and extended endurance. Longterm endurance testing of full-size fuel cell modules has demonstrated the extended endurance capability of potassium titanate matrix cells, the long-term performance stability of the anode catalyst, andmore » the suitability of a lightweight graphite structure for use at the anode in an alkaline fuel cell. In addition under the program, a full-size alkaline fuel cell module has completed 5,000 hours of a planned 20,000-hour test to a cyclical load profile. The continuous load profile consists of 60 minutes at open circuit followed by 30 minutes at 200 ASF which simulates the operation of a Regenerative Fuel Cell Energy Storage System in low earth orbit.« less
  • The pneumatic storage of energy is one of the few economical storage processes which can be considered at present for large quantities of energy. Present Compressed Air Energy Storage (CAES) plants are designed on the basis of construction and operating experience at Huntorf, the world's first air-storage plant (1). That means, that the turbine of the plant is equipped with combustors to increase the power output during turbine operation, and to reduce the volume and cost of the air storage facility as well as the quantity and cost of the required charging energy (2). In this paper it is explainedmore » that the Brown Boveri CAES turbomachinery is able to burn a variety of different fuels. This opens in many cases the possibility to choose a cheaper or better available fuel to reduce furthermore the operating cost of this kind of power plant.« less