Electricity power plants

Table 32. Biofuels Utilization and Production and Biomass-Fueled Electric Power Plant Capacities in the United States ...

Long Valley in east-central California, the Valles Caldera of north-central New Mexico, and the Yellowstone region of northwestern Wyoming. The sizes of these magma bodies may be in excess of 1000 km of fluid rock at temperatures in excess of 650°C. It has been estimated that only 2 km of magma could provide enough energy to operate a 1000-MW electric power plant for 30 years. 

The former Soviet Union constmcted a 262-km, 508-mm dia experimental coal slurry line between the Belovo open-pit coal mine in Siberia s Kuznets basin to an electric power plant at Novosibirsk, using technology developed by Snamprogetti. Testing began in late 1989 and tentative plans call for constmction of two much larger slurry pipelines, each 3000-km long, with capacity to move a total of 33 x 10 t/yr to industrialized areas near the Ural Mountains (27,33). 

Electric power generation using biomass as a fuel is economic in situations where the cost of the fuel is competitive with that of fossil fuels. The cost of a commercially available biomass steam—electric power plant is about 1500/kW for a wood-fired facility. If wood can be obtained at a cost of 2.00/GJ ( 2.10 X 10 /Btu), the total cost of power for base-load operation would be about 0.05/kWh. If wood or agricultural wastes are available at... 

San Diego Gas Electric s expander is installed in parallel to a major city gate station. This type of system could be installed on a pressure reducing station supplying natural gas to an electric power plant. Large regulator stations serving industrial customers are another possible application. 

The utilities in our modern society are so much a part of our lives that it is hard to imagine how we survived without them. An electric power plant generates electricity to heat and light our homes in addition to providing power for the television, refrigerator, and electric toothbrush. When our homes were heated with wood fires, home-made candles were used... 

Such a reference system is shown in Fig. 9.3a. The overall efficiency of the conventional electric power plant is (for simplicity the subscript O for overall efficiency is dropped from here onwards) the (demand) electrical load is unity. The ratio of heat to electrical demands is Ai>, so that the demand heat load is taken as Ajj. The efficiency of the heat only boiler is tjb so the fuel energy required for the boiler is i.e. there are heat losses ApKI/tjq)— 1 involved before heat is delivered to district or process heating. 

In the United States the passage of the CAAAs of 1990, and their implementation starting in 1995, was an attempt to solve the acid rain problem mainly by reducing SO, emissions from electric power plants. While significant reductions in SO, emissions have occurred, and there already has been... 

States, companies and consumers are saving millions of dollars in energy costs since new computers, mostly replacement systems, are being plugged in at a rate of over thirty million a year. Just as importantly, society receives the environmental benefit of reducing the need for additional electric power plants. 

The poor efficiencies of coal-fired power plants in 1896 (2.6 percent on average compared with over forty percent one hundred years later) prompted W. W. Jacques to invent the high temperature (500°C to 600°C [900°F to 1100°F]) fuel cell, and then build a lOO-cell battery to produce electricity from coal combustion. The battery operated intermittently for six months, but with diminishing performance, the carbon dioxide generated and present in the air reacted with and consumed its molten potassium hydroxide electrolyte. In 1910, E. Bauer substituted molten salts (e.g., carbonates, silicates, and borates) and used molten silver as the oxygen electrode. Numerous molten salt batteiy systems have since evolved to handle peak loads in electric power plants, and for electric vehicle propulsion. Of particular note is the sodium and nickel chloride couple in a molten chloroalumi-nate salt electrolyte for electric vehicle propulsion. One special feature is the use of a semi-permeable aluminum oxide ceramic separator to prevent lithium ions from diffusing to the sodium electrode, but still allow the opposing flow of sodium ions. 

If all the heat absorbed were converted into work, the efficiency would be 1, or 100 percent. If none of the heat absorbed was converted into work, the efficiency would be 0. The first law of thermodynamics limits the efficiency of any heat engine to 1 but does not prevent an efficiency of 1. The efficiency of practical heat engines is always less than 1. For example, the efficiency of a large steam turbine in an electric power plant is about 0.5, which is considerably more efficient than the typical 0.35 efficiency of an auto engine. When two objects at different temperatures are m... 

For a heat engine like a steam turbine in an electric power plant the low temperature is determined by the outdoor environment. This temperature is about 300 K. Engineering considerations limit the high temperature to about 800 K. The maximum efficiency according to Carnot is 0.63 or 63 percent. No matter how skilled the builders of a steam turbine, if the temperatures are 300 K and 800 K, the efficiency will never exceed 63 percent. When you realize that the efficiency can never be larger than about 63 percent, a realizable efficiency of 50 percent looks quite good. 

Suppose 10,000 V, j (e.g., from an electrical power plant generator) is input to a transformer where the number of secondary turns is 75 times more than the number of primary turns. Then the voltage from the secondary will be 75 X 10,000 = 750,000... 

This very high voltage level is actually produced by the secondary of the transformers at a modern commercial electrical power plant the 750,000 is connected to the high voltage transmission lines (thick wire cables) that are used to transport the elec-... 

When the power is a large number, as in the case of an electric power plant, it is convenient to express the power in megawatts (MW) where one megawatt equals one million watts. An electric power of 1,000,000,000 watts would be expressed as 1,000 MW. A large coal-burning or nuclear power plant produces about 1,000 MW of electric power. The sum total of the electric power produced by all electric power plants is expressed m units of gigawatts (GW). One gigawatt equals one billion watts. An electric power of 1,000,000,000,000 watts would be expressed as 1,000 GW. 

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