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Power generation costs
Published in Jin Zhong, Power System Economic and Market Operations, 2018
Combustion gas turbines using natural gas as the fuel are complementary to coal-fired steam turbines. The power output of gas turbine can be easily adjusted to follow quick load changes. The capital cost of a gas-fired power plant is much lower compared to that of a coal-fired power plant, but the fuel, usually natural gas, is relatively expensive. Many gas turbine-based power plants are designed to be easily switched to using oil as fuel, when the price of natural gas becomes high. Which type of power plant is more economical depends on the total fuel cost over the lifetime of the power plant. From carbon dioxide emission viewpoints, natural gas is more environmental friendly than coal. It is estimated that for the same amount of power output, the carbon dioxide produced by a gas-fired power plant is around half of that produced by a coal-fired power plant.
Regional impacts on air quality and health of changing a manufacturing facility’s grid-boiler to a combined heat and power system
Published in Journal of the Air & Waste Management Association, 2023
Elaheh Safaei Kouchaksaraei, Ali Khosravani Semnani, Kody M. Powell, Kerry E. Kelly
Although CHP systems yield net energy savings, implementing CHP results in an increase in on-site natural gas usage and local emissions, and can result in local adverse health effects. Since CHP systems combust natural gas in turbines at high temperatures, they result in higher NOx formation than a boiler [23] and consequently can lead to adverse health impacts. A study in Iran evaluated the health effects of NOx, CO, SO2, and PM10 (particles with a diameter of 10 and smaller) emissions from a natural gas fired power plant and identified nitrates (which are the result of atmospheric reaction involving NOx) as having the greatest adverse health effects [24]. This Iranian study considered the following health effects: restricted activity days, chronic bronchitis, cardiovascular hospital admissions, respiratory hospital admissions, asthma attacks, congestive heart failure, chronic cough, and long-term mortality; it attributed 4.55 million (2000 USD) of health costs to nitrate, which accounted for the 94% of total health costs 4.86 million (2000 USD) resulting from all studied emissions [24].
Performance analysis and comparison of cryogenic CO2 capture system
Published in International Journal of Green Energy, 2021
Rui Sun, Hua Tian, Chunfeng Song, Shuai Deng, Lingfeng Shi, Ke Kang, Gequn Shu
Yuan, Pfotenhauer, and Qiu (2014) proposed the cryogenic process which applied one compression and two expansion steps, the first expansion was used for cooling the flue gas to the CO2 freezing point and the second one was for recovering the residual pressure of flue gas. An optimal process intermediate pressure for minimizing the energy penalty of the whole process was obtained. Xu and Lin (2017) investigated the cryogenic CO2 capture process for the LNG (liquid natural gas)-fired power plant, introduced residual flue gas into the expander for compensating mechanical work consumed by the compressor, and investigated the appropriate process operating conditions for capture performance improvement. Yousef et al. (2018) studied the process integration of cryogenic biogas upgrading, indicated the expander can be used for driving the compressor and inducing temperature drop in the feed stream, thus enabling further cooling potential in the heat exchangers. Willson et al. (2019) proposed a novel Advanced Cryogenic Carbon Capture (A3C) process by using a moving bed of metallic beads as a heat transfer medium and frost capture surface, and the techno-economic evaluation results indicates that this process has comparable costs with the reference amine-absorption method, and shows additional potential for further improvement.
Integrative technology hubs for urban food-energy-water nexuses and cost-benefit-risk tradeoffs (I): Global trend and technology metrics
Published in Critical Reviews in Environmental Science and Technology, 2021
Ni-Bin Chang, Uzzal Hossain, Andrea Valencia, Jiangxiao Qiu, Qipeng P. Zheng, Lixing Gu, Mengnan Chen, Jia-Wei Lu, Ana Pires, Chelsea Kaandorp, Edo Abraham, Marie-Claire ten Veldhuis, Nick van de Giesen, Bruno Molle, Severine Tomas, Nassim Ait-Mouheb, Deborah Dotta, Rémi Declercq, Martin Perrin, Léon Conradi, Geoffrey Molle
Geothermal, heat or thermal energy within the earth, is a clean and renewable source of energy, and is used for different applications such as heating water for bathing, heating buildings, and generating electricity. Due to its potential, the installed capacity of geothermal power plants is expected to grow to 140–160 GW by 2050 (Ellabban et al., 2014). Geothermal energy is green due to its insignificant CO2 emissions compared to other technologies. According to the literature, carbon emissions are about 0.06 kg CO2e/kWh for a single-flash power plant compared to 0.59 kg CO2e/kWh for a natural-gas-fired power plant, and 1.13 kg CO2e/kWh for a coal-fired power plant (DiPippo, 2012). Note that CO2e is defined as the equivalent emissions of CO2 when other greenhouse gases are involved. Descriptions of geothermal energy technologies such as electricity production (G1-EP), direct use (G2-DU) and heat pump (G3-HP) are given in Supplementary Information (S1.1). The technological considerations of some of the decentralized geothermal energy technologies are described in Table S3 (Supplementary Information).