Thermal plant electricity generation applications

Thermal power plant is more commonly associated with very large central power stations. The capital cost for thermal power plant, in terms of cost per installed kilowatt of electrical generating capacity, rises sharply for outputs of less than some 15 MW. It is for this reason that thermal power plant is not usually considered for industrial applications unless it is the combined cycle or combined heat and power modes. However, for cases where the fuel is of very low cost (for example, a waste product from a process such as wood waste), then the thermal power plant, depending on output, can offer an excellent choice, as its higher initial capital cost can be offset against lower running costs. This section introduces the thermal power cycle for electrical generation only. 

Stationary power is the most mature application for fuel cells. Stationary fuel cell units are used for backup power, power for remote locations, stand-alone power plants for towns and cities, distributed generation for buildings, and cogeneration where excess thermal energy from electricity generation is used for heat. 

Heat for district heating and potable water could be produced using off-peak electric power without reducing the electricity generation of the plant. In a cogeneration mode, an electric output reduction grants substantial thermal energy that could be used for non-electric applications. 

The preceding section reviewed the application of popular prime movers for the generation of electrical power only. In the conversion of fuel energy to electricity it is shown that heat is rejected, either in the exhaust of a diesel or gas turbine or, alternatively, in the condenser of a thermal power plant. It can be seen that by applying these machines to provide both heat and electricity the total energy recovery can be much greater and efficiency thereby improved. Combined heat and power (CHP) schemes of this nature are well-established methods of producing both heat and power efficiently and economically. 

Twenty-one countries generate 8,000 MW of electricity from geothermal resources, and 11,300 thermal megawatts are used for applications such as aquaculture, greenhouse operations, and industrial processing. Domestic power plants generate 2,800 MW at 5 to 7.5 cents per kilowatt-hour. 

According to the design concept, the UNITHERM can be used as a source of energy for the generation of electricity, district heating, seawater desalination and process steam production either in a complex or to meet specific demands. The purpose of the NPP would impact not only the mix of components but may also determine the characteristics of the reactor [II-5]. For instance, the use of steam at low parameters for district heating and potable water production allows the application of a turbine generator unit operated at backpressure. This sufficiently increases total plant efficiency and allows the use of the thermal siphon as an... 

While the steam generator efficiency t)sg 0.92), the steam turbine efficiency (j/x = 0.9-0.92), the generator efficiency (t/q > 0.98), and the corresponding efficiency for the power plant s electrical auxiliary power consumption ( /aux io 0.93) all have relatively high values above 0.9, the net efficiency of a coal-fired steam power plant is mainly affected by the thermal efficiency of the cycle /th,id> which today is about 0.55. Besides the minimization of losses by an optimized flue gas heat utilization, the application of optimized turbine blading, or the reduction of the auxiliary power consumption, the main potential for enhancing the overall power plant efficiency can be seen in increasing the live steam parameters. 

While various fuel cell systems are emerging as alternatives for power generation, the carbonate fuel cell plants are attractive for applications where the superior efficiency or combined high quality heat and power are desired. Over fifty units ranging in 250 kW to 1 MW size have been in field operation worldwide. These units have shown 45 to 48% LHV electrical conversion efficiencies and overall thermal efficiency approaching in combined heat and power (CHP) applications. The plant emissions are ultra clean. These attributes... 

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