MW Of Electrical Power Research Articles

Rational Exergy Management Model based metrics for minimum carbon dioxide emissions and decarbonization in Glasgow

Addressing climate change is an urgent issue that requires effective and sustainable solutions at multiple scales from the building to the district and city scales. This study focuses on the avoidable carbon dioxide emissions responsibilities due to exergy mismatches between supply and demand at multiple scales based on the Rational Exergy Management Model. Nine key metrics for decarbonization are presented with analyses of three case studies in Glasgow, including a university campus area, and urban emissions scenarios. The existing campus district system involves 42 MW boiler capacity for heat supply and 3.35 MW electric power and heat supply with a combined heat and power system that is responsible for 80.97 kg carbon dioxide per operating hour at design conditions. The system may shift towards carbon neutrality if the combined heat and power system capacity increases to at least 27.3 MW electric power and the boiler is eventually banned. A potential expansion of the district network with solar prosumer buildings indicates that the optimum number of Exergy Stars as a new rating is four out of five when embodiments for solar prosumer buildings are considered. Urban emissions scenarios for Glasgow indicate about 20 MtCO2eq of urban consumption-based emissions in 2020 that are analyzed up to 2030 and 2050 under different decarbonization scenarios. Remaining urban emissions are linked to inefficiencies where exergy mismatches cause emissions responsibilities in the energy system. In comparison to the decarbonization index in the urban emissions scenarios for Glasgow, the increased exergy match at 0.87 is closest to its 2045-year value in the renewable energy based green-growth scenario. The results are useful for guiding other urban areas to embark on an effective approach for mitigation and bring society to a better balance with the planet. Districts and cities can utilize these metrics to upscale climate mitigation and minimize emissions more rapidly.

Energy consumption optimization of CO2 capture and compression in natural gas combined cycle power plant through configuration modification and process integration

Currently, natural gas combined cycle (NGCC) power plants account for a quarter of global electricity power supply and lead to greenhouse gas emissions. Carbon capture and storage (CCS) is one of the most effective technologies to reduce carbon emissions in the short term. However, the monoethanolamine (MEA)-based CO2 absorption and compression process is energy-intensive, which significantly reduces the power generation efficiency of NGCC. In addition, the waste hot and cold energy from NGCC and liquefied natural gas (LNG) regasification process, which are generally wasted, can be recovered for the CCS process. Therefore, this study aims to reduce the energy consumption of the carbon capture process and recover waste LNG cold energy and hot energy in the NGCC through configuration modification and process integration. The results show that the energy consumption of CO2 regeneration in the proposed CO2 capture process configuration is reduced by 18.03 %, and the net power efficiency of the NGCC plant increases from 48.88 % to 50.10 %. Furthermore, a cascade two-stage organic Rankine cycle is integrated into the system for waste heat recovery, which can generate 5.04 MW electric power and reduce the efficiency penalty of the plant from 13.72 % to 10.29 %. By contrast, the alternative application of LNG cold energy to the CO2 compression process reduces compression power by 3.95 MW with a lower footprint and utility requirement while the efficiency penalty is decreased by 3.15 %.

Piezoelectric energy harvester for wind turbine blades based on bistable response of a composite beam in post-buckling

A bistable piezoelectric energy harvester (PEH) is presented for harvesting power from vibrations occurring at low frequencies, as is the case of wind turbine blades. The axial compressive prestress of a piezoelectric composite beam at post-buckling serves as the bistability source, leading to high mechanical to electric power conversion. An in-house harvesting circuit connected to the piezoelectric terminals is used for demonstration of its harvesting power capabilities. A finite element (FE) model is used to analyze and optimize the coupled nonlinear electromechanical response of the PEH, including structure and circuit. A physical prototype has been manufactured and tested for validation of the electromechanical design and the FE modeling approach. Predictions and measurements indicate an increase of harvested power with applied prestress up to a transition point, where a sudden drop in power occurs. Good comparison between numerical and experimental results verified the modeling approach, whereas deviations related to physical boundary conditions at large compressive forces affected the prediction of the transition point in harvested power. The harvester produced 1.32 mW of electrical power under tonal base excitation of 1 g at 8 Hz. Hence, the nonlinear PEH has demonstrated its capability to harvest energy at frequencies much lower than its first linear modal frequency and could thus serve as a promising solution for powering IoT devices and sensors in large vibrating structures.

Energy, exergy, and exergoeconomic (3E) evaluation of a hybrid multigeneration system based on a solar tower

This study focuses on analyzing a multigeneration system that integrates conventional energy systems with renewable energy sources to boost efficiency and decrease the use of fossil fuels. The aim is to find a financially viable and low-carbon solution for sustainable development. The performance of the proposed multigeneration system, which can simultaneously supply fresh water, hydrogen, heating, and cooling, is evaluated by analysis. The energy, exergy, and economic analyses in this assessment all use thermodynamic equations. In addition, the effects of different variables on the operating results of the hybrid system were examined and the economic viability of the power plant was assessed by calculating the net present value (NPV). The results of the analysis show that this system can supply 47.297 MW of electrical power, 8.287 MW of heating power, 11.222 MW of cooling power, 2.49 kg/s of fresh water, and 18.06 kg/h of hydrogen. The use of renewable solar energy leads to a 26.47 % reduction in fuel consumption and an annual reduction in CO2 emissions of 18,230 tons. The calculation results in a total system cost rate of 9299 USD/hour and a unit price of cogeneration of 34.5 USD/GJ. At the end of the 20-year lifespan of the power plant, a payback period (PP) of 2 years and 11 months was expected, which corresponds to a net profit of USD 200 million at present value.

Exergoeconomic and exergoenvironmental analyzes of a new biomass/solar-driven multigeneration energy system: An effort to maximum utilization of the waste heat of gasification process

In addition to improving the sustainability and thermodynamic efficiencies of an energy conversion system, a solar/biomass-driven integrated energy system can also reduce environmental impacts. The current work presents a detailed evaluation (thermodynamic simulation and exergoenvironmental and exergoeconomic analyzes) of a solar/biomass-powered multigeneration energy system (MGES). Accordingly, four units were considered for electric power generation. A linear Fresnel concentrator (LFC)-driven solar farm, a municipal solid waste (MSW) gasification cycle, an alkaline water electrolyzer (AWE) unit (to produce hydrogen gas), and a multi effect desalination (MED)-based Seawater desalination cycle are also considered in the MGES. A multi-objective optimization (regarding the technical, cost, and environmental objective functions) was also developed for the offered MGES. The proposed configuration for the MGES has a new components process that had not been reported in the publications. The power generation level was improved by utilizing the energy available in waste heat in the different downstream units. The offered MGES can generate 154.1 MW of electrical power, ∼ 280 kg per day of hydrogen gas, and 265.4 m3/h of fresh water. Meantime, the offered MGES can 38.8 % and 32.2 % efficient in terms of energy and exergy, respectively. Besides, the LCOE value and the environmental impacts index for the offered MGES were approximately 3.82 USD/GJ and 0.545 Pts/GJ, respectively. Also, raising the syngas temperature at the inlet of the combustion chamber can be a reasonable decision from the exergetic, economic and (especially) environmental standpoints.

Recovery of Flared Natural Gas with High CO<sub>2</sub> Content Using SOFC CHP System: Feasibility Study for Neem-Field, Sudan

Flared natural gas emissions are one of the main sources of environmental pollution and global warming. To recover this gas, the presence of impurities like CO2 in high concentrations forces oil producers to escape from investing in such intensive processing. Several implementations of no flaring methods have been reported in the literature, however, there have been limited concerning the bulk-CO2 natural gases. This research developed an innovative idea for the use of the SOFC CHP system to recover flared bulk-CO2 associated gas of Neem-Field in Western Sudan. The exergy of the system and the performance of the SOFCs are investigated in this paper, in addition to environmental and economic analysis. The simulation (Cycle-Tempo©) results demonstrate that the proposed system can generate 1 MW electrical power and 0.068 MW thermal energy with efficiency approached 43.3% (based on LHV). The exergy analysis showed that 38% of system losses occurred in the air preheaters. Instead of conventional gas-burning, recovering the flared gas reduced the equivalent CO2 GHGs emissions by 80%. Overall, the novel solution found to be environmentally friendly, and economically appealing with a total capital investment estimated to be US$1.175 million and a cost of electricity (COE) of 4.07 cents per kWh.

Ultra-Wideband Tunable Microwave Photonic Filter Based on Thin Film Lithium Niobate

In signal processing of the growing semaphore, a microwave photonic filter (MPF) is capable of dealing with high-frequency signals, offering the advantages of high bandwidth, easy tuning, and more. This paper presents an efficient tunable microwave photonic filter that features a wideband tuning capability and narrow-band filtering effect based on the lithium niobate on insulator (LNOI) material platform. A multi-mode waveguide race-track type microring resonator has been designed, along with a thermal electrode that utilizes the thermo-optical effect of lithium niobate to adjust the microring resonator. The packaged device has been tested, with a wideband tunable range of 4.7~38.2 GHz achieved. This allows for cross-band continuous tuning across the C-band to Ka-band range. When supplied with 29.1 mW of electric power, the thermal tuning efficiency reaches 9.2 pm/mW, enabling high-frequency tuning of up to 38.2 GHz. The filter possesses a high resolution, exhibiting a 3 dB bandwidth of 662 MHz.

Multi-variable assessment/optimization of a new two-source multigeneration system integrated with a solid oxide fuel cell

The integration of renewable energies can improve the thermodynamic performance and increase the popularity and commercialization of the energy production system. Moreover, the exploitation of renewables in the form of cascade energy systems with multigeneration goals has been able to overcome many restrictions and penalties. Meantime, fuel cells are efficient, carbon-free, and promising energy conversion technologies can act as a storage system and improve the sustainability of the energy system. In this article, a new two-source multigeneration system (TS/MGS) based on a biomass fuel and a geothermal source is introduced and evaluated. The upstream process of the considered system is based on a municipal solid waste (MSW)-gasification process-fueled solid oxide fuel cell (SOFC) stack. Besides, the downstream process is comprised of a geothermal source based on a triple-flash cycle, an ejection-based refrigeration process, a water electrolysis cycle, and a domestic water heater unit. The offered TS/MGS is capable of generating electricity, cooling load, heating load, and hydrogen fuel. Converting MSW to energy, in addition to producing efficient energy, can help waste management in urban communities. The operation of the offered TS/MGS was comprehensively investigated from thermodynamic, cost and environmental standpoints. Moreover, the optimal behavior of the TS/MGS is compared under two different decision-making approaches (based on a tri-objective optimization algorithm). Under the considered design parameters, the considered TS/MGS can provide about 3.92 MW of electric power, 2.19 MW of cooling load, ∼ 1.55 MW of heating load, and 0.1 g/s of hydrogen fuel to the consumer (at a thermal efficiency of 33.5% and an exergy efficiency of 61%). The values of total unit cost of products and levelized total carbon dioxide emissions were 0.0211 $/kWh and 0.21 kg/kWh. Under the TOPSIS decision-making approach, relatively more optimal exergoeconomic and environmental outcomes can be achieved compared to the LINMAP decision-making approach. However, the thermodynamic behavior under the LINMAP decision-making approach is more optimal than the TOPSIS decision-making approach.

An innovative biomass-driven energy systems for green energy and freshwater production with less CO2 emission: Environmental and technical approaches

Considering the current crisis of fossil energies, the exploitation of renewables and green technologies is necessary and unavoidable. Additionally, the design and development of integrated energy systems with two or more output products and the maximum usage of thermal losses in order to improve efficiency can boost the yield and acceptability of the energy system. In this regard, this paper develops a comprehensive multi-aspect assessment of the operation of a new solar and biomass energies-driven multigeneration system (MGS). The main units installed in MGS are three electric energy generation units based on a gas turbine process, a solid oxide fuel cell unit (SOFCU) and an organic Rankine cycle unit (ORCU), a biomass energy conversion unit to useful thermal energy, a seawater conversion unit into useable freshwater, a unit for converting water and electricity into hydrogen energy and oxygen gas, a unit for converting solar energy into useful thermal energy (based on Fresnel collector), and a cooling load generation unit. The planned MGS has a novel configuration and layout that has not been considered by researchers recently. The current article is based on presenting a multi-aspect evaluation to study thermodynamic-conceptual, environmental and exergoeconomic analyzes. The outcomes indicated that the planned MGS can produce about 6.31 MW of electrical power and 0.49 MW of thermal power. Furthermore, MGS is able to produce various products such as potable water (∼0.977 kg/s), cooling load (∼0.16 MW), hydrogen energy (∼1.578 g/s) and sanitary water (∼0.957 kg/s). The total thermodynamic indexes were calculated as 78.13% and 47.72%, respectively. Also, the total investment and unit exergy costs were 47.16 USD per hour and 11.07 USD per GJ, respectively. Further, the content of CO2 emitted from the desgined system was equal to 10.59 kmol per MWh. A parametric study has been also developed to identify influencing parameters.

Multi-Channel Long-Distance Audio Transmission System Using Power-over-Fiber Technology

To establish stable communication networks in harsh environments where power supply is difficult, such as coal mines and underwater, we propose an effective scheme for co-transmission of analog audio signals and energy. By leveraging the advantages of optical fibers, such as corrosion resistance and strong resistance to electromagnetic interference, the scheme uses a 1550 nm laser beam as the carrier for analog audio signal propagation, which is then converted to electrical energy through a custom InGaAs/InP photovoltaic power converter (PPC) for energy supply and information transfer without an external power supply after a 25 km fiber transmission. In the experiment, with 160 mW of optical power injection, the scheme not only provides 4 mW of electrical power, but also transmits an analog signal with an acoustic overload point (AOP) of 105 dBSPL and a signal-to-noise ratio (SNR) of 50 dB. In addition, the system employs wavelength division multiplexing (WDM) technology to transform from single-channel to multi-channel communication on a single independent fiber, enabling the arraying of receiving terminals. The passive arrayed terminals make the multi-channel long-distance audio transmission system using power-over-fiber (PoF) technology a superior choice for establishing a stable communication network in harsh environments.

Application of nanomaterial based alkaline electrolyzer for hydrogen production in renewable energy-driven system: Multi-criteria assessment, environmental and exergoeconomic approaches

An alkaline electrolyzer is a traditional equipment to generate hydrogen. Improving the yield of electrolyzers has recently captured much attention. In this regard, the utilization of carbon-coated nanomaterial structures is a state-of-art method. On the other hand, considering the current crisis of fossil energies, the exploitation of renewables and green technologies is necessary and unavoidable. Additionally, the design and development of integrated energy systems with two or more output products and the maximum usage of thermal losses to enhance productivity can increase the flexibility and acceptability of the energy system. In this regard, the current paper develops a framework for the performance of a new solar and biomass energies-driven multigeneration system (MGS). The main units installed in MGS are three electric energy generation units based on a gas turbine process, a solid oxide fuel cell unit (SOFCU) and an organic Rankine cycle unit (ORCU), a biomass energy conversion unit to useful thermal energy, a seawater conversion unit into useable freshwater, a unit for converting water and electricity into hydrogen energy and oxygen gas via a nanomaterial-based alkaline electrolyzer, a unit for converting solar energy into useful thermal energy (based on Fresnel collector), and a cooling load generation unit. The planned MGS has a novel structure and layout that has not been considered by researchers in previous papers. The current article is based on presenting a multi-aspect evaluation in order to investigate thermodynamic-conceptual, environmental and exergoeconomic analyzes. The outcomes indicated that the planned MGS can produce about 6.31 MW of electrical power and 0.49 MW of thermal power. Furthermore, MGS is able to produce various products such as potable water (∼0.977 kg/s), cooling load (∼0.16 MW), hydrogen energy (∼1.578 g/s) and sanitary water (∼0.957 kg/s). The overall energy and exergy productivities were measured as 78.13% and 47.72%, respectively. Also, the total investment and unit exergy costs were 47.16 USD per hour and 11.07 USD per GJ, respectively. Further, the content of carbon dioxide released from the planned system was equal to 10.59 kmol per MWh. A parametric study has been also developed to identify influencing parameters.

Exergoeconomic evaluation of a new carbon-free hydrogen and freshwater production system based on biomass gasification process

Abstract This article is based on the conceptual-thermodynamic design and exergoeconomic investigation of a new poly-generation system driven by a biomass fuel (i.e. wood). In the proposed energy system, a Rankine power process, a gasification process, a desalination process (i.e. multi-effect desalination, MED) and a water electrolyzer (i.e. solid oxide electrolyzer cell, SOEC) are installed in a hybrid form. Electric energy, fresh water and hydrogen gas are the useful output products of the proposed energy system. The proposed energy system indicates an innovative framework for the carbon-free production of these products, which introduces an environmentally friendly and efficient schematic. The findings of the research indicated that the proposed energy system is capable of producing more than 1.8 MW of electric power. Other useful output products of the proposed energy system include hydrogen fuel and fresh water, which were calculated as 0.0036 kg/s and 9.92 m3/h, respectively. It was also calculated that the proposed energy system can achieve energetic and exergetic efficiencies equal to 37.1% and 17.8%, respectively. The total unit exergy cost of the products and the exergy destruction rate of the proposed energy system were equal to 15.9$/GJ and 8640 kW, respectively. Parametric analysis is also presented in order to identify the input variables affecting the performance of the energy system. Further, the behavior of the system under four different types of biomass was evaluated and compared.

Performance of small reservoirs in Tulang Bawang Watershed for microhydro power plant

Recurring floods in the Tulang Bawang River have led to significant losses. In response, the government and local engineers have taken steps to manage flood events and harness excess water for electrical energy generation through the construction of five small reservoirs in the Tulang Bawang watershed. This study evaluates the performance of these reservoirs as micro-hydro power plants, with the aim of mitigating energy challenges in Lampung Province. To achieve this goal, we collected and analyzed hydrological data and calculated the potential electrical power output for each reservoir. By utilizing a 50- meter waterfall height, the sub-watersheds of Way Giham, Way Umpu, and Way Tahmi, with a combined water holding capacity of approximately 2 million cubic meters, are capable of generating around 3 MW of electrical power per reservoir. Similarly, Way Tuba and Way Basei sub-watersheds offer a potential of approximately 4 MW of electrical power per reservoir. Based on these calculations, it is evident that the small reservoirs in the Tulang Bawang watershed hold substantial potential for contributing to the electrical power supply, thereby addressing Lampung Province's energy challenges. These findings underscore the significance of utilizing available water resources to meet energy demands and promote sustainable development in flood-prone areas.

Towards renewable green energy produced by prickly pear living plant

ABSTRACT In recent years, low power consumption and portable devices have been developed that will be connected and used everywhere. However, this explosion will bring critical challenges to electricity consumption. In this work, copper and zinc electrodes are embedded in prickly pear plant as an electricity generation has been analysed and evaluated. Many experimental setups have been performed to determine the optimum method to collect the maximum amount of energy from the living plant. They study the influence of distance between electrodes, influence of the electrode’s size, influence of the electrode’s depth, effect of the couple electrodes number, and effect of series and parallel connection to harvested energy. Therefore, a combination of series and parallel connection among the leaves can be installed to harvest higher voltage and current. The experimental results show that 58,8 mW electrical power can be harvested using 18 pairs of electrodes embedded in 6 leaves. The produced energy is used to power up low-power devices such as a calculator or a light emitting diode (LED) and can be stored in a capacitor or a battery.

Techno-Economic and Environmental Assessment of Municipal Solid Waste Energetic Valorization

In 2019, Chile generated 20 million tons of waste, 79% of which was not properly disposed of, thereby providing an attractive opportunity for energy generation in advanced thermochemical conversion processes. This study presents a techno-economic and environmental assessment of the implementation of Waste-Integrated Gasifier-Gas Turbine Combined Cycle (WIG-GTCC) technology as an alternative for Municipal Solid Waste (MSW) treatment. The studied case assesses the conversion of 14.61 t·h−1 of MSW, which produces a combustible gas with a flow rate of 34.2 t·h−1 and LHV of 5900 kJ·kg−1, which, in turn, is used in a combined cycle to generate 19.58 MW of electrical power. The proposed economic assessment of the technology uses the energy generation processes as a reference, followed by a model for an overall economic evaluation. The results have shown that the profit could be up to USD 24.1 million, and the recovery of investment between 12 and 17 years would improve the environmental impacts of the current disposal technology. The WIG-GTCC has the most efficient conversion route, emitting 0.285 kg CO2eq/kWh, which represents 48.21% of the potential yield of global warming over 100 years (GWP100) of incineration and 58.51% of the GWP100 of the standard gasification method. The WIG-GTCC would enable the energetic valorization of MSW in Chile, eliminate problems associated with landfill disposal, and increase opportunities for decentralized electricity generation.

Preliminary consideration of the beam screen for the super proton-proton collider

This study evaluates the functional requirements of the Super Proton-proton Collider (SPPC) beam screen in view of the CEPC-SPPC project about to be built in China and aims to prove the feasibility of using the scaled FCC-type beam screen. Moreover, the study puts forward several feasible updated schemes with extra-cooling to optimize the cryogenic efficiency under the 12.8 W/m synchrotron radiation (SR) heat load and decrease the leaked SR power to the cold bore. The power distribution calculated by Synrad+ is imported into the Ansys workbench to get the exact thermal profile. The results show that the new scheme can restrict the temperature rise within 1 K, with a 30 g/s mass flow rate of the coolants. Such a profile can save over 1.3 MW electric power per turn.

Hydropower potential of municipal water supply schemes in Osun State: Case study of Okinni Dam, Osogbo, Nigeria

Continuous increase in energy demand has been tied to population increase and improved economic well-being of the people. As the world’s population continues to grow geometrically, energy supply has been a major concern, especially, since the last two decades. Nigeria is no exception to this and it’s even worse affected, because of its lack of adequate planning for its teeming population. From the present predicament of the country, it is obvious that other sources of energy generation mostly renewable - hydro-electric, solar, and wind which are more reliable and environmental friendly be explored as the dependency on the generated power using fossil fuel to the national grid has not helped in anyway. Hence, the need to explore other power alternatives, especially the renewables one. This study was therefore designed to investigate the potential of municipal water supply schemes in Osun State as a means of developing small hydropower plant using Okinni dam as a case study. Field survey was conducted through which key information about Okinni dam was obtained. The dam gives a conversion advantage with its water flow rate ranging between 7.71m3/s and 12.85m3/s based on the season of the year and also a height (head) above ground level of 20m. The collected field parameters were utilised in the standard hydropower equations. The results obtained from the analysis gives a theoretical all year round of 3.1MW of electrical power. Comparing this result with the minimum power demand of 2.1MW and maximum power demand of 3.7MW of the inhabitants of the Okinni town, the Okinni dam services, Ede water works and some residential building at Ede water works, would require a two daily operations whereby the load are carefully selected on 12 hourly bases (Day and Night). This study has thus established the potential and viability of the construction of a small hydropower (SHP) on Okinni dam which will improve the town’s commercial and industrial enterprise; hence, this project is recommended for construction.

43+T Grenoble Hybrid Magnet: From Final Assembly to Commissioning of the Superconducting Outsert

The Grenoble Hybrid magnet is a modular platform using resistive and superconducting technologies to produce various DC high magnetic field and flux configurations for the scientific community. They range from 43 T in 34 mm diameter with 24 MW electrical power to 9 T in 800 mm diameter when the superconducting coil is used alone. Thanks to the ongoing upgrade of the electrical power installation at LNCMI-Grenoble to 30 MW, and possibly to 36 MW, the opportunity to increase the total field well above 45 T in the near future is anticipated and studied in detail. The key design parameters will be recalled comprising the specifically developed Nb-Ti/Cu conductor, the large-bore outsert superconducting coil, the magnet cryostat with its structure including the eddy-current shield, the cryogenic line for the interconnection with the cryogenic satellite and the dedicated 150 l/h He liquefaction plant. All components of the superconducting part of the hybrid magnet platform have been built, tested and delivered to LNCMI-Grenoble, where integration and final assembly are continuing. The status of the project will be presented with the main problems encountered and solved. It includes the recent commissioning tests of the cryogenic satellite producing the pressurized superfluid He at 1.8 K as well as the successful powering tests of the specially developed current leads at ultimate current and under fully degraded cooling conditions simulating the worst-case accidental scenario.

A hybrid fuel cell, solar thermal collector, and coal-fired power plant; energetic, exergetic, and emission analysis

ABSTRACT Although the nonrenewable energy-driven power plants have major limitations, but at present, more than 80% of the energy needed all over the world is met through these power plants. Among them, almost one-third is supplied through coal-fired plants. However, the major limitation in the exploitation of coal fuel is the increase in environmental harms due to the increased greenhouse gas emissions. In this regard, it is necessary to adopt solutions and integrate these plants with other clean and green energy production cycles in order to reduce the emission of pollutants and improve their behavior. In this paper, the thermodynamic-conceptual evaluation of a new coal-fired plant driven by lignite is developed. Besides that, the plant is coupled with a solid oxide fuel cell and two independent solar units (both based on parabolic trough collector (PTC) arrays) in order to reduce the environmental harms of coal. Additionally, the introduced power plant consists of two power generation units based on a Rankine cycle and a gas turbine-based cycle. Therefore, the introduced plant can produce electric power and hot water. Further, the integration of cycles based on renewable technologies can reduce environmental pollution and improve plant’s efficiency. Moreover, a comprehensive comparison is presented when changing power plant fuel from lignite to anthracite. The conceptual design of solar units based on the geographical characteristics of city of Karaj is also provided. The outcomes indicated that the gas released from the plant during the combustion process is approximately 94.1 kg per second. The considered plant can produce almost 270.2 MW of electric power and approximately 1572 kg of hot water per second. Additionally, the energetic efficiency was equal to 69.72% and exergetic efficiency was equal to 34.93%. The findings also indicated that the size of solar unit 1 under both types of anthracite and lignite coal is the same; while, by changing the type of coal from lignite to anthracite, the size of solar unit 2 can be reduced by almost 6.5 times.

Design parameters impacting electricity generation from horizontal multilateral closed-loop geothermal systems in Hot Dry Rock

This article presents a parametric study of closed loop geothermal systems (CLGSs) design with multiple lateral horizontal wells, drilled in Hot Dry Rocks (HDRs), by developing a coupled finite element method (FEM) model for the problem of transient heat production in the reservoir and an Organic Rankine Cycle (ORC) model for electricity generation evaluation at the surface. The design parameters are well spacing and geometry, the number of wells, injection flow rate, energy losses along the well, and ORC working and cooling fluid mass flow rates. The study evaluates how these parameters affect the evolution of the spatial distribution of the temperature of the rock mass, the circulation fluid temperature leaving the reservoir, and the rate of electrical power generation with seasonal variations in surface air temperature.Analysis shows that the temperature evolution of the reservoir over a wide range of realistic properties is not influenced significantly by the rock and fluid properties, injection flow rate, nor well length and diameter and is a function of time only, and the initial rock mass and injection fluid temperatures. Therefore, in a CLGS with a hexagonal array of horizontal wells, the distance between the wells, beyond which the performance of a hexagonal array of wells is practically indistinguishable from that of a single isolated well, is 200 m over 30 years; i.e., the produced fluid temperature is practically unaffected by heat extraction from neighboring wells, regardless of reservoir properties. For smaller well spacing (100 m), the system shows practically negligible interaction in the first 15 years and only a small impact (∼1%) during the next 15 years of heat production.The performance of a CLGS mainly depends on the fluid temperature leaving the reservoir (falling rapidly in the first few months) and ambient surface temperature (varying over a year). Using data from the FORGE Utah site, analysis suggests that a CLGS with four 1 km horizontal wells operated at 2 m3/min/well can produce ∼5 MW of electrical power during cold months and none during hot months.