Policy Implications of Greenhouse Warming Mitigation, Adaptation, and the Science Base (1992) / Chapter Skim
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24 Energy Supply Systems
24 Energy Supply Systems
Pages 330-375
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From page 330... ...
Rather, the panel indicates the range of possible energy supply systems in the United States and their implications for greenhouse gas emissions at the current time. The panel leaves to more specialized analyses the detailed consideration of system design and selection.
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(19891. 120 130 110 100 90 CD 80 O 70 m ~ 60 C: 50 40 30 20 10 o -- - Emissions Atmospheric CO2 '' i' I' 1960 1970 1980 1988 YEAR FIGURE 24.1 Cumulative emissions of CO2 from fossil fuel burning since 1959 and observed increases in the atmosphere at Mauna Loa.
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From page 332... ...
For a discrete refined product, the value differs: for example, 18.5 is appropriate for automotive gasoline (Marland, 1983~. While CO2 can be intimately and accurately related to fossil fuel combustion, there are other, less well characterized, greenhouse gas emissions from the fossil fuel cycle.
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Renewables Provide 7 of 82 Quads Oil 41% Gas 21% \ \ ' \ ,/ Coal 23% I/ 7°/O U.S. Renewable Energy Supply (1988)
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One estimate is that for every direct use of liquid fuel, CO2 emissions equivalent to those that would result from the use of an additional 11.8 percent of petroleum products are produced in activities upstream from the final products at the refinery. Under this accounting system, these greenhouse gas emissions should be charged TABLE 24.2 Electric Power Generation in the United States, 1988 Carbon EmissionsGenerationPercentage of Fuel (Million tons)
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From page 335... ...
Energy supply systems purely for electricity generation are discussed first. Then energy supply systems on a broader basis are examined.
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From page 336... ...
Coal Coal is the most abundant fossil fuel resource in the United States and is the principal fuel powering the economies of several other nations including China and the former USSR. Coal is used primarily for electric power generation, but also for industrial process heat and, in some cases (mostly in developing countries)
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From page 337... ...
Clean Coal Technology Program, and other PFBC demonstration plants are being constructed in Europe. Integrated gasification combined cycle technology has been demonstrated at the 100-MW scale at the Cool Water Facility operated by Southern California Edison.
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Finally, future developments for coal-fired power plants conceivably could include control technology for the removal of CO2 from flue gases. This option, which could apply generally to fossil fuels, is discussed later in this chapter.
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From page 339... ...
Combined cycle systems have not been considered a serious option in the planning of future power generation until very recently, largely because of the uncertainty in the availability of natural gas and the poor reliability of GTCC systems in the past. The latter was not due to inherent technical barriers but to a lack of attention from the industry.
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From page 340... ...
The unattractive economics of nuclear energy is due to a host of problems. Another concern is the current lack of radioactive waste disposal facilities in the United States.
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A brief description of the state of the art can be found in Appendix G In summary, acceptance of nuclear energy as a principal source of energy supply would change in important respects the prospects of greatly reducing the discharge of CO?
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From page 342... ...
Each of these energy supply systems is presumably sustainable at some level with little or no net CO2 release other than from fossil fuel investments in plant capital and fossil fuel supplements to system operation. In the latter case, especially, it is apparent that CO2 emissions are a function of energy supply system design and are not inherent in system utilization (as is the case with fossil fuel burning)
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From page 343... ...
of fossil fuels in heating and industrial applications at a cost savings of 25 to 35 percent (Solar Energy Research Institute, 1990~. The currently exploited high-quality resource in California is, however, relatively rare.
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To the degree that this may occur, the energy supply structure can change to accommodate different ways of supplying energy and of reducing emissions from the generation of that energy. Therefore it is useful to examine some technologies as elements in an energy system instead of viewing electricity production alone.
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From page 345... ...
transformation processes (incoming fuels are transformed to Primary inputs Energy Sources Block 1 Transfor mation Processes A Block 2 Industrial Gas Gases Separation Block 3 Block 3A Transfor- Final mation Consump B tion Block 4 Block 5 FIGURE 24.3 Simplified representation of an integrated energy system.
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From page 346... ...
One of the simplest IESs, the co-generation system using natural gas to generate both electricity and heat, can be traced, for example, from gas to combined cycle to electricity, process heat, and steam. Another system can utilize two primary energy sources, nuclear energy and natural gas, for both electricity and process heat generation, with much lower CO2 emissions than would result from burning gas alone.
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From page 347... ...
Under these conditions, one might want to resort soothe conventional air-fired gas turbine combined cycle system and also eliminate the gas separation system for the synthesis gas. The CO2 must then be removed downstream.
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, the influence on other environmental issues (e.g., low maintenance intensity should lead to less soil erosion than occurs with agricultural crops) , the effect on other greenhouse gas emissions (e.g., fertilization could increase N2O emissions)
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From page 349... ...
Advances in biotechnology could be useful in altering either the biomass yield or the structure of the plant. It has been suggested that displacement of fossil fuels for electric power generation could be accomplished with little or no difference in the cost of electricity other than the difference in delivered cost of fuel (see, for example, Wright and Ehrenshaft, 1990)
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From page 350... ...
The cost of fuel cells today is about $2500/kW, a significant part of which is the cost of the reformer to produce hydrogen. If fuel cells could be used as an element in an integrated energy system, where hydrogen is supplied by other means, the overall economics could change.
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From page 351... ...
How to integrate such a cable into a power system from the viewpoint of operations reliability has not been seriously studied. Successful development of high-temperature superconducting materials may significantly alter the economics of electrical power generation and transmission, but the time scale is highly uncertain.
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From page 353... ...
Steinberg's estimate is that 19 percent of the energy value of coal would be available in such a scheme with no oxidation of fuel carbon, and the fraction would be higher for liquid and gaseous fuels with higher hydrogen content. Cost-Effectiveness The method used in determining the cost-effectiveness of energy supply options is described in Appendix J
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From page 354... ...
For example, the price of energy from solar photovoltaics has constantly been decreasing and may continue to do so. It is for this reason that the panel made a deliberate decision to avoid projections of price or of the potential of a particular technology to replace fossil fuels.
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mix is equivalent to the CO2 tax that would be needed to make nuclear energy competitive with the current U.S. energy supply (approximately $51/t co21.
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U.S. mix 5 Coal, advanced pulverized 5.1 Coal, running cost of 2.0-3.5C depreciated plant Gas, combined cycle Nuclear Hydroelectric Geothermal Solar photovoltaic Solar thermal/gas hybrid Wind Biomass 0.7 0.86 0.9 3 3_45d 4.7 - 8.6e 5.6 4.9 10.3 14.3 5.1-13.9 4.8-6.0 0.41 o o 0.18 o o NA NA NA NA to 51 9 NA 76 177 1 to 127 NA to 14 NOTE: NA = Not applicable (i.e., cost less than U.S.
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From page 357... ...
Figure 24.6 shows the age distribution of fossil fuel plants still operating in 1986. · The use of gas to replace coal with either conventional plants or combined cycle technologies is perceived as limited by domestic supplies of natural gas.
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(1989) pointed out that the recoverable resources of conventional natural gas are about 35 times the current annual usage, a paper one year later (Fisher, 1990)
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Biomass Windpower Geothermal Hydropower Photovoltaics Solar Thermal Electric OTEC Solar Buildings/ Industrial Process Heat Facilitators o o o o C o o o C FIGURE 24.7 The significance of institutional factors for renewable energy options. SOURCE: Solar Energy Research Institute (1990)
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From page 360... ...
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a A is Ed .
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From page 365... ...
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From page 367... ...
Additional supply-side options that should be evaluated include · regulatory and economic incentives to increase the capital turnover rate · carbon or greenhouse gas taxes, and · technology or emission standards (U.S. Department of Energy, 19891.
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OTHER BENEFITS AND COSTS Although there are many costs associated with changing the energy supply strategy of the nation, there are a variety of benefits. First, with the
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A number of actions recommended by the Alternative Energy Committee under its "focused research and development strategy" are summarized below: Fossil Energy . Increase the efficiency of fossil generating equipment by using currently available, high-efficiency options such as the gas turbine/steam tur bine combined cycle.
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Nuclear Energy · On the strength of public acceptability and global reactor studies performed under the focused research and development strategy, fund an industry-led or industry-managed program to develop and demonstrate an advanced reactor.
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In addition, as mentioned earlier, another report, forthcoming from the National Research Council, will focus on nuclear energy. The challenge is to develop a range of options for providing energy with maximum efficiency and minimum greenhouse gas emissions so that society can respond as it evaluates the threat of greenhouse warming.
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To the extent that these problems are solved, solar energy can usefully replace a portion of the U.S. energy supply.
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1990. Technology and Cost of Recovering and Storing Carbon Dioxide from an Integrated Combined Cycle.
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1989. Solar Hydrogen: Moving Beyond Fossil Fuels.
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From page 375... ...
1988. Ecological advantages of natural gas over other fossil fuels.
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