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Computer generated data on the performance of the cogeneration energy conversion system are presented. Performance parameters included fuel consumption and savings, capital costs, economics, and emissions of residual fired process boilers.
Industrial cogeneration and utility pr systems were analyzed and a conceptual design study was conducted to evaluate the economic feasibility of a coal gasifier power plant for NASA Lewis Research Center. Site location, plant size, and electric power demand were considered in criteria developed for screening and selecting candidates that could use a wide variety of coals, including that from Ohio. A fluidized bed gasifier concept was chosen as the baseline design and key components of the powerplant were technically assessed. No barriers to environmental acceptability are foreseen. If funded, the powerplant will not only meet the needs of the research center, but will reduce the commercial risk for utilities and industries by fully verifying and demonstrating the technology, thus accelerating commercialization.
The value analysis technique used is straightforward. Maximum allowable life-cycle system cost for the cogeneration system is determined as the sum of the present value of fuels displaced plus the present value of revenues from exported power. Each conventional fuel displaced is described by a unit cost in the first year, a uniform annual consumption rate, and a uniform annual escalation rate for unit cost. Exported energy flows are treated the same as displaced energy.
The essential elements of the cogeneration system configuration to be captured were the displacement of thermal energy by collection and use of the Brayton exhaust stream, and the sale back to the utility of any electricity production in excess of on-site requirements. In contrast to simply dumping these energy flows, their use or sale obviously serves, by itself, to increase gross value of the solar thermal energy system. Net allowable cost of the parabolic dish modules may or may not be increased, however. A consideration is that the waste heat capture and delivery subsystems are not free. This study does not address the incremental cost of adding waste heat capture, transport, and conversion (to steam, if necessary). It does compute a value for the thermal energy thereby displaced. This value can serve as a first-round input to any detailed economic evaluation of waste heat recovery.
An advanced state-of-the-art steam turbine-generator developed to serve as the power conversion subsystem for the Department of Energy's Sandia National Laboratories' Solar Total-Energy Project (STEP) is described. The turbine-generator, which is designed to provide 400-kW of net electrical power, represents the largest turbine-generator built specifically for commercial solar-powered cogeneration. The controls for the turbine-generator incorporate a multiple, partial-arc entry to provide efficient off-design performance, as well as an extraction control scheme to permit extraction flow regulation while maintaining 110-spsig pressure. Normal turbine operation is achieved while synchronized to a local utility and in a stand-alone mode. In both cases, the turbine-generator features automatic load control as well as remote start-up and shutdown capability. Tests totaling 200 hours were conducted to confirm the integrity of the turbine's mechanical structure and control function. Performance tests resulted in a measured inlet throttle flow of 8,450 pounds per hour, which was near design conditions.
The fuel cell energy systems are designed with and without a utility connection for emergency back-up power. Sale of electricity to the utility during periods of low plant demand is not considered. For each of the three industrial applications, conceptual designs were also developed for conventional utility systems relying on purchased electric power and fossil-fired boilers for steam/hot water. The capital investment for each energy system is estimated. Annual operating costs are also determined for each system. These cost estimates are converted to levelized annual costs by applying appropriate economic factors. The breakeven electricity price that would make fuel cell systems competitive with the conventional systems is plotted as a function of naphtha price. The sensitivity of the breakeven point to capital investment and coal price is also evaluated.
Information and data for 26 industrial processes are presented. The following information is given for each process: (1) a description of the process including the annual energy consumption and product production and plant capacity; (2) the energy requirements of the process for each unit of production and the detailed data concerning electrical energy requirements and also hot water, steam, and direct fired thermal requirements; (3) anticipated trends affecting energy requirements with new process or production technologies; and (4) representative plant data including capacity and projected requirements through the year 2000.
A comparative assessment of three fuel cell systems for application in different buildings and geographic locations is presented. The study was performed at the NASA Lewis Center and comprised the fuel cell design, performance in different conditions, and the economic parameters. Applications in multifamily housing, stores and hospitals were considered, with a load of 10kW-1 MW. Designs were traced through system sizing, simulation/evaluation, and reliability analysis, and a computer simulation based on a fourth-order representation of a generalized system was performed. The cells were all phosphoric acid type cells, and were found to be incompatible with gas/electric systems and more favorable economically than the gas/electric systems in hospital uses. The methodology used provided an optimized energy-use pattern and minimized back-up system turn-on.
Applications of coal fired atmospheric fluidized bed gas turbine systems in industrial cogeneration are identified. Based on site-specific conceptual designs, the potential benefits of the AFB/gas turbine system were compared with an atmospheric fluidized design steam boiler/steam turbine system. The application of these cogeneration systems at four industrial plant sites is reviewed. A performance and benefit analysis was made along with a study of the representativeness of the sites both in regard to their own industry and compared to industry as a whole. A site was selected for the conceptual design, which included detailed site definition, AFB/gas turbine and AFB/steam turbine cogeneration system designs, detailed cost estimates, and comparative performance and benefit analysis. Market and benefit analyses identified the potential market penetration for the cogeneration technologies and quantified the potential benefits.
Results were arrived at by utilizing and expanding on information presented in the literature. The results were analyzed and compared with those for simple gas turbine and combined cycles for both utility power generation and industrial cogeneration applications. The efficiency and specific power of simple gas turbine cycles can be increased as much as 30 and 50 percent, respectively, by the injection of steam into the combustor. Steam-injected gas turbines appear to be economically competitive with both simple gas turbine and combined cycles for small, clean-fuel-fired utility power generation and industrial cogeneration applications. For large powerplants with integrated coal gasifiers, the economic advantages appear to be marginal.
PRESTO, a COSMIC program, handles energy system specifications and predicts design efficiency of cogeneration systems. These systems allow a company to use excess energy produced to generate electricity. PRESTO is utilized by the Energy Systems Division of Thermo Electron Corporation in the custom design of cogeneration systems.
The Alternative Energy Systems Seminar was held on March 30, 1978, and was sponsored jointly be the Southwest District Office of the U.S. Department of Energy and JPL. The seminar was an experiment in information exchange with the aim of presenting, in a single day, status and prospects for a number of advanced energy systems to a diverse, largely nontechnical audience, and to solicit post-seminar responses from that audience as to the seminar's usefulness. The major systems presented are: (1) Solar Photovoltaic; (2) Geothermal; (3) Cogeneration Power; (4) Solar Thermal; (5) Solar Heating and Cooling; (6) Wind Energy; and (7) Systems Considerations.
The technical and economic feasibility of incorporating thermal energy storage components into the proposed Twin Cities District heating project was evaluated. The technical status of the project is reviewed and conceptual designs of district heating systems with and without thermal energy storage were compared in terms of estimated capital requirements, fuel consumption, delivered energy cost, and environmental aspects. The thermal energy storage system is based on cogeneration and the storage of heat in aquifers.
Results are compared using coal derived low and intermediate heating valve fuel gases and a conventional distillate. The results indicate that steam injection provides substantial increases in both power and efficiency within the available compressor surge margin. The results also indicate that these performance gains are relatively insensitive as to the type of fuel. Also, in a cogeneration application, steam injection could provide some degree of flexibility by varying the split between power and process steam.
Present and future relatively small (30 MW) energy systems, such as solar thermal electric, photovoltaic, wind, fuel cell, storage battery, hydro, and cogeneration can help achieve national energy goals and can be dispersed throughout the distribution portion of an electric utility system. Based on current projections, it appears that dispersed storage and generation (DSG) electrical energy will comprise only a small portion, from 4 to 10 percent, of the national total by the end of this century. In general, the growth potential for DSG seems favorable in the long term because of finite fossil energy resources and increasing fuel prices. Recent trends, especially in the institutional and regulatory fields, favor greater use of the DSGs for the future.
An integrated gasifier combined cycle (IGCC) system which simultaneously produces electricity, process steam, and liquid hydrogen was evaluated and compared to IGCC systems which cogenerate electricity and process steam. A number of IGCC plants, all employing a 15 MWe has turbine and producing from 0 to 20 tons per day of liquid hydrogen and from 0 to 20 MWt of process steam were considered. The annual revenue required to own and operate such plants was estimated to be significantly lower than the potential market value of the products. The results indicate a significant potential economic benefit to configuring IGCC systems to produce a clean fuel in addition to electricity and process steam in relatively small industrial applications.
The utilization potential of the point focusing parabolic dish is identified. Its main design parameters are summarized. Performance tests and the utilization of the collector as primary energy source in a food-water-power complex are described. Process heat, heat storage, heat transfer, and cogeneration are discussed.
Energy consumption at the Goldstone Echo Deep Space Station (DSS 12) is predicted and quantified for a future station configuration which will involve implementation of proposed energy conservation modifications. Cogeneration by the utilization of diesel waste-heat to satisfy site heating and cooling requirements of the station is discussed. Scenarios involving expanded use of on-site diesel generators are presented.