FLUID BED AUGMENTED CAES SYSTEMS

Compressed Air Energy Storage (CAES) systems are potentially attractive for future electric utility load leveling applications. A potential long-term weakness of the conventional CAES concept is its reliance on clean petroleum fuels during the power generation period. This consumption of petroleum could be completely eliminated by the use of coal-fired fluid bed combustors in second generation CAES plants. A large number of CAES power system configurations are possible using atmospheric fluid bed combustion (AFBC) and pressurized fluid bed combustion (PFBC). The fuel consumption rates for these systems are generally comparable to those for oil-fired CAES systems. The future prognosis for using PFBC in CAES systems looks good. Recent corrosion and erosion experiments in fluid bed systems suggest that gas turbines with acceptable lifetimes in fluid bed systems suggest that gas turbines with acceptable lifetimes are a distinct possibility. The commercial status of these systems depends on the outcome of extensive corrosion/erosion testing in static and rotating test rigs. CAES systems using AFBC may be an attractive alternative to using PFBC, although the materials problem would then be transferred from the turbine to the high temperature heat exchanger surface. A reasonable expectation for the date of commercialization of fluid bed augmented CAES system ranges from 10 to 15 years

Technical and economic assessment of fluidized bed augmented compressed air energy-storage system. Volume II. Introduction and technology assessment

The results are described of a study subcontracted by PNL to the United Technologies Research Center on the engineering feasibility and economics of a CAES concept which uses a coal fired, fluidized bed combustor (FBC) to heat the air being returned from storage during the power production cycle. By burning coal instead of fuel oil, the CAES/FBC concept can completely eliminate the dependence of compressed air energy storage on petroleum fuels. The results of this assessment effort are presented in three volumes. Volume II presents a discussion of program background and an in-depth coverage of both fluid bed combustion and turbomachinery technology pertinent to their application in a CAES power plant system. The CAES/FBC concept appears technically feasible and economically competitive with conventional CAES. However, significant advancement is required in FBC technology before serious commercial commitment to CAES/FBC can be realized. At present, other elements of DOE, industrial groups, and other countries are performing the required R and D for advancement of FBC technology. The CAES/FBC will be reevaluated at a later date when FBC technology has matured and many of the concerns now plaguing FBC are resolved. (LCL

Technical and economic assessment of fluidized bed augmented compressed air energy storage system. Volume III. Preconceptual design

A technical and economic assessment of fluidized bed combustion augmented compressed air energy storage systems is presented. The results of this assessment effort are presented in three volumes. Volume III - Preconceptual Design contains the system analysis which led to the identification of a preferred component configuration for a fluidized bed combustion augmented compressed air energy storage system, the results of the effort which transformed the preferred configuration into preconceptual power plant design, and an introductory evaluation of the performance of the power plant system during part-load operation and while load following

Conceptual design of compressed air energy storage electric power systems

Conceptual design studies have been conducted to identify Compressed Air Energy Storage (CAES) systems which are technically feasible and potentially attractive for future electric utility load-levelling applications. The CAES concept consists of compressing air during off-peak periods and storing it in underground facilities for later use. During peak-load periods the air would be withdrawn, heated by recuperation and combustion and expanded through turbines to generate power. By using off-peak electricity for compression and stored air for peak-load generation, the resulting oil consumption would be about 40 per cent of that consumed by conventional gas-turbine peaking plants. The turbomachinery requirements for this type of system could be met using existing equipment with relatively modest modifications. Although the study discussed herein focused on the storage of air in hydraulically compensated, mined, hard-rock caverns, the compressed air could also be stored in underground aquifers or leached-out salt cavities. Conventional underground excavation technology could be used to construct these storage caverns. A geological survey of the north-central and north-east regions of the United States indicated that sufficient siting opportunities exist such that a prudently designed CAES plant should have little long-term adverse impact on the environment. The competitive position of CAES relative to conventional generation alternatives is highly dependent on utility-specific factors. The cost of electric energy from CAES is generally competitive with costs from conventional peak-shaving systems such as gas turbines and will improve as low-cost off-peak energy from nuclear plants becomes available.