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Electric Energy Efficiency in Power Production & Delivery
Published in Clark W. Gellings, The Smart Grid: Enabling Energy Efficiency and Demand Response, 2020
As interest in electric energy efficiency increases, practitioners and others interested in energy efficiency are questioning whether the scope of end-use energy efficiency should be broadened to electric uses in power delivery systems and in power plants. Interestingly, these two aspects of efficiency are only briefly mentioned in any of the smart grid initiatives currently in play. Efficiency advocates are questioning whether investments made within power delivery systems and power plants to reduce electricity demand may be as advantageous as those made in end-use efforts with consumers. Power plant improvements in electricity consumption could include methods to improve overall efficiency, therefore, increasing the heat rate (decreasing Btu input per kWh output) of the power plant. Power delivery system improvements could include use of efficient transformers and better voltage and reactive power control, among others. Each of these are directly related to an informed view of the smart grid.
Electric Power Production
Published in J. Lawrence, P.E. Vogt, Electricity Pricing, 2017
Thermal generating units have a heat rate characteristic, which is the amount of Btu of fuel that must be burned to produce a kWh (or MWh) of output. Thus, heat rate is a measure of the efficiency of electricity generation. A heat rate of 9,000 Btu/kWh yields a higher generation efficiency than a 10,000 Btu/kWh heat rate. Heat rates vary between different generation technologies and between specific units within the same technology, e.g., one coal-fired steam unit is more (or less) efficient than another. The heat rate of a specific unit also varies somewhat as a function of its level of power production (MW). The heat rate is highest at the unit’s minimum output rating because of the amount of fuel required to stabilize the burn and spin the turbine. As the power output of a unit increases, its heat rate declines somewhat but not in a precise linear relationship, and it then increases to some extent as the output approaches the unit’s maximum rating.3
Localized vs Central Station Power Generation
Published in Neil Petchers, Combined Heating, Cooling & Power Handbook: Technologies & Applications, 2020
The fact that a gas turbine exhausts large quantities of air/gases at temperatures around those of a fairly efficient steam cycle (1,000°F or 538°C) allows for significant enhancements in overall cycle efficiency. As shown in Figure 3-5, if the exhaust from a gas turbine is fed to a heat recovery steam generator (HRSG), the steam that is raised can drive a steam-powered cycle. The steam cycle converts about 15 to 20% of the rejected heat energy into additional electric power, resulting in a combined-cycle thermal efficiency of about 43 to 53%. On a heat rate basis, this plant will require only about 6,400 to 8,000 Btu/kWh (6,750 to 8,440 kJ/kWh), compared with 10,000 to 11,000 Btu/kWh (10,550 to 11,600 kJ/kWh) for conventional-cycle plants.
Quantification of the water-energy-carbon nexus of the coal fired powerplant in water stressed area of Pakistan
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2020
Naeem H Malik, Faheemullah Shaikh, Laveet Kumar, M. S. Hossain
Energy efficiency of the powerplants is inversely related to the CO2 emissions, reason being that more efficient plants require lesser heat rate (amount of heat needed to generate one MWH of electricity) meaning they will burn lesser fuel and release lesser CO2 for the same amount of electricity generated. Figure 7, Figure 8, Figure 9, Figure 10, Figure 11, Figure 12, Figure 13, Figure 14, Figure 15, Figure 16 depicts the CO2 emissions of various advanced power-generation technologies. It also shows the impact of dry cooling technology on the emissions of the EPTL. Due to the lesser efficiency, the dry cooling scenario results in the highest CO2 emissions of the energy project reaching as high as 6.1 million metric tons in 2050 followed by reference, supercritical and EFCC scenarios which reach to 5.8, 5.36 and 4.64 million metric tons, respectively. IGCC technology shows promising results in CO2 emissions as well reaching 4.33 million metric tons annually by 2050.
Optimal capacity allocation in accordance with renewable energy sources: the US electricity market
Published in International Journal of Ambient Energy, 2023
Umut Golbasi, Bilgi Yilmaz, A. Sevtap Selcuk-Kestel
Table 1 summarises certain specifications of energy sources. Power plant heat rate measures the efficiency of an electricity generator and denotes how much energy is used per kW of production. Since renewable energy does not burn fuel to produce heat and electricity, this metric is not applicable for hydro, wind and solar power. The next three specifications are related to the costs such as capital (Cap. Cost), fixed operation and maintenance cost (Fixed OM), fuel and operation and maintenance cost (Var. OM) of power plants. The last three variables relate to emission rates of power plants.