Simultaneous Power Generation Research Articles

Thermodynamic analysis of supercritical water gasification combined with a reversible solid oxide cell

The low cost of electricity in some areas facilitates the adoption of high-temperature electrolysis plants for the large-scale storage of electricity. Supercritical water gasification (SCWG) is a promising method of syngas production from wet biomass. Additionally, it is a potential source of steam for electrochemical plants. However, the commercialisation of standalone SCWG systems is hindered by low efficiency and high operating cost. Accordingly, we propose the integration of SCWG with a reversible solid oxide cell (rSOC) to realise simultaneous syngas or power generation and wet biomass conversion. This technique would make the process feasible in terms of energy, allowing engineers to use SCWG to combine power generation with fuel production. The wet syngas from the SCWG is fed to the rSOC powered by excess renewable electricity in electrolysis mode, where steam is reduced to H2 to produce dry syngas with a higher calorific value. The energy efficiency of the proposed system is 91% in electrolysis mode and 47% in fuel cell mode. The electrolysis increases the syngas yield by a factor of thirteen and the use of total syngas generates twelve times more power in fuel cell mode compared to the use of only fresh syngas from SCWG.

Simultaneous Solar‐driven Steam and Electricity Generation by Cost‐effective, Easy Scale‐up MnO2‐based Flexible Membranes

Harvesting solar energy in an effective manner for steam and electricity generation is a promising technique to simultaneously cope with the energy and water crises. However, the construction of efficient and easy scale‐up photothermal materials for steam and electricity cogeneration remains challenging. Herein, we report a facile and cost‐effective strategy to prepare MnO2‐decorated cotton cloth (MCx). The wide adsorption spectrum and excellent photothermal conversion ability of the in situ‐formed MnO2 nanoparticles make the MCx to be advanced photothermal materials. Consequently, the hybrid device integrated with MCx as the photothermal layer and the thermoelectric (TE) module for electricity power conversion exhibits an extremely high evaporation rate of 2.24 kg m−2 h−1 under 1 kW m−2 irradiation, which is ranked among the most powerful solar evaporators. More importantly, during solar evaporation, the hybrid device produces an open‐circuit voltage of 0.3 V and a power output of 1.6 W m−2 under 3 Sun irradiation, and outperforms most of the previously reported solar‐driven electricity generation devices. Therefore, the integrated device with synergistic solar‐thermal utilization opens up a green way toward simultaneous solar vapor and electric power generation in remote and resource‐constrained areas.

Photocatalytic Fuel Cells for Simultaneous Wastewater Treatment and Power Generation: Mechanisms, Challenges, and Future Prospects

Technological advancement is accompanied by excessive consumption of fossil fuels and affluent uses of chemical substances in many sectors, including transportation and manufacturing companies, and so on. Being an exhaustible resource, the excessive use of fossil fuels and of chemical substances may lead to a serious energy crisis in the long run, and it may additionally impose environmental pollution. Attempts have been made in the solution of such serious issues from every nook and corner. Nonetheless, no method has been found to be a panacea in waste water treatment and subsequent beneficiaries. One of the attempts in the solution to such issues is the application of photocatalytic technology, which could serve as a dual function in environmental remediation and clean energy production. A photocatalytic fuel cell is a tool developed for the recovery of energy from organic wastes. A rational cell construction needs the fabrication of photoelectrodes, the design of a photoanode and a photocathode chamber, in addition to an ion-transport membrane for pollution treatment and electricity generation. In this review, comprehensive fundamental assessments and recent developments in the design of photocatalytic fuel cells, their applications, future prospects, and challenges are covered.

Energetic and exergetic analyses of a closed-loop pressure retarded membrane distillation (PRMD) for low-grade thermal energy utilization and freshwater production

Low-grade thermal energy is abundant but hard to utilize because of the low energy availability. Recently, research on low-grade thermal energy has been conducted to enhance the energy availability. One of these approaches, pressure-retarded membrane distillation (PRMD), has been proposed. It was designed by combining the operating principles of membrane distillation and pressure-retarded osmosis. In this paper, a closed-loop PRMD is proposed to include the structure of thermo-osmotic energy conversion (TOEC) to enable simultaneous desalination and power generation. Mathematical modeling and energetic/exergetic analyses are performed through MATLAB, to evaluate the feasibility of new process. In addition, a sensitivity analysis is conducted to analyze the energy efficiency of the process. The results reveal that the closed-loop PRMD system requires the lowest heat input (1.74 kW/m2) and increases the electrical energy production (1.91 W/m2) to achieve the same water permeation, compared with existing processes. In addition, unlike the TOEC process, water and electrical energy can be produced simultaneously. Moreover, the exergy destruction of the closed-loop PRMD is observed to be the lowest. Thus, the proposed closed-loop PRMD is a promising solution for desalination and energy harvesting systems from low-grade thermal energy.

Multifunctional Superelastic Graphene-Based Thermoelectric Sponges for Wearable and Thermal Management Devices.

Power generation through harvesting human thermal energy provides an ideal strategy for self-powered wearable design. However, existing thermoelectric fibers, films, and blocks have small power generation capacity and poor flexibility, which hinders the development of self-powered wearable electronics. Here, we report a multifunctional superelastic graphene-based thermoelectric (TE) sponge for wearable electronics and thermal management. The sponge has a high Seebeck coefficient of 49.2 μV/K and a large compressive strain of 98%. After 10 000 cyclic compressions at 30% strain, the sponge shows excellent mechanical and TE stability. A wearable sponge array TE device was designed to drive medical equipment for monitoring physiological signals by harvesting human thermal energy. Furthermore, a 4 × 4 array TE device placed on the surface of a normal working Central Processing Unit (CPU) can generate a stable voltage and reduce the CPU temperature by 8 K, providing a feasible strategy for simultaneous power generation and thermal management.

A Wave‐Driven Piezoelectric Solar Evaporator for Water Purification

AbstractInterfacial solar vapor generation is an emerging technology that has the potential to alleviate the current global water crisis. However, water evaporation is an energy‐intensive phase‐change process and thus suffers from an inherently low evaporation yield. New stable and environmentally tolerant materials that can reduce energy requirements and accelerate water evaporation stand out from various studies. In this contribution, a piezoelectric ultrathin nanofilm is integrated into a solar evaporation membrane for simultaneous power generation and water activation. The resulting evaporator is used to continuously convert the wave energy in the ocean into electrical energy. It is found that the electrical energy generated by the evaporator can activate water in adjacent regions, facilitating water evaporation with an additional improvement of over 20% compared to an equivalent non‐piezoelectric evaporator. This paper presents the innovation of a promising membrane evaporation prototype based on the integration of wave‐triggered electricity and water activation.

Sequential anaerobic-aerobic treatment of rice mill wastewater and simultaneous power generation in microbial fuel cell

Microbial fuel cells (MFCs) have attracted widespread interest due to their capability to generate power while treating wastewater. In the present investigation, rice mill wastewater (RMW) was treated in a dual-chamber MFC with a biological cathode (MFCB), in which anaerobic treatment was provided in the anode compartment, and aerobic treatment was enployed in the cathode compartment. The performance was compared with an identical MFC with an abiotic cathode (MFCA). During continuous operation, the hydraulic retention time (HRT) of the anode compartments of both MFCs was kept at 12 h. The maximum volumetric power density obtained in MFCB (379.53 mW/m3) was lower than MFCA (791.72 mW/m3). Similarly, the maximum open-circuit voltage (OCV) and operating voltages were 0.519 V and 0.170 V for MFCB, while for the MFCA, they were 0.774 V and 0.251 V, respectively. The internal resistance of MFCA was 372.34 Ω while the MFCB showed a higher internal resistance of 533.89 Ω. The linear sweep voltammetry and cyclic voltammetry also demonstrated high electrochemical activity in MFCA compared to MFCB. However, MFCB has shown a higher chemical oxygen demand (COD) removal efficiency (96.8%) than MFCA (88.4%) under steady-state conditions. Both anaerobic and aerobic degradation of organic substrates significantly reduced the COD of RMW. Furthermore, the absence of an expensive catalyst in the cathode substantially reduces the cost of the system. The electrical performance of the system can be enhanced by employing novel cathode material with surface modification.

Molten carbonate fuel cells for simultaneous CO2 capture, power generation, and H2 generation

This article presents a new technology for the generation of power and steam, or other process heat, with very low CO2 emissions. It is well known that cogeneration of electricity and steam is highly efficient and that amine units can be used to remove CO2 from combustion flue gas, but that the amine unit consumes a significant amount of steam and power, reducing the overall system efficiency. In this report, the use of molten carbonate fuel cells (MCFCs) to capture CO2 from cogen units is investigated and shown to be highly efficient due to the additional power that they produce while capturing the CO2. Furthermore, the MCFCs are capable of reforming methane to hydrogen simultaneous to the power production and CO2 capture. This hydrogen can either be recycled as fuel for consumption by the cogen or MCFCs, or exported to an independent combustion unit as low carbon fuel, thereby decarbonizing that unit as well. The efficiency of MCFCs for CO2 capture is higher than use of amines in all cases studied, often by a substantial margin, while at the same time the MCFCs avoid more CO2 than the amine technology. As one example, the use of amines on a cogeneration unit can avoid 87.6% of CO2 but requires 4.91 MJ/kg of additional primary energy to do so. In contrast, the MCFCs avoid 89.4% of CO2 but require only 1.37 MJ/kg of additional primary energy. The high thermal efficiency and hydrogen export option demonstrate the potential of this technology for widespread deployment in a low carbon energy economy.

Significance of Aniline blue in liquid phase dye sensitized Photo Galvanic cell for Solar power generation and Storage by using Ascorbic acid and Sodium Lauryl Sulphate chemicals

A primary source of renewable energy is solar energy. This is the one of the most resourceful sources of energy for the future. The photogalvanic cells as described in the present work are energy devices as they provide a route for simultaneous solar power generation and its storage. The study of photogalvanics of Aniline blue dye (photo-sensitizer)- Ascorbic acid (reductant)-Sodium Lauryl Sulfate (surfactant) has been done in basic medium at low intense light with aim of searching relatively proper combination of chemicals like photosensitizer, reductant and surfactant for further increasing the efficiency of these cells. The best conditions for cell have also been observed for optimal cell performance. The solar conversion efficiency, fill factor, cell performance (as t1/2), power at power point, open circuit potential and equilibrium current at 10.4 mWcm-2 have been observed of the order of 2.31%, 0.2445, 130 min, 240.24 W, 1485 mV and 750A respectively.

Solar-driven simultaneous desalination and power generation enabled by graphene oxide nanoribbon papers

We constructed an alkaline-earth metal ion-mediated graphene oxide nanoribbon paper for desalination and power generation. The evaporation device exhibits photothermal conversion efficiency of 91.5% and a power density of 0.11 W m−2.

Investigation on Microbial Fuel Cells Fabricated from Recyclable Materials for Energy Generation and Wastewater Treatment

Microbial fuel cells (MFC) have gained focus due to their diversity in operating conditions & substrates for the generation of sustainable green energy. In the present study, novel MFC has been fabricated using the recyclable aluminum can as air-cathode and graphite rod as anode for the treatment of domestic wastewater and simultaneous power generation. Three different substrate (COD) concentrations, high (>800 mg.L-1), medium (250 mg.L-1 - 800 mg.L-1) and low (<250 mg.L-1) were used. The maximum COD removal efficiencies, voltage generation, power densities were found to be 80%, 0.71 V, and 304.46 mW.m-2 respectively in high strength wastewater setup. In both medium and low strength wastewater setups, after 288 hours, the COD was reduced below 50 mg.L-1 thus limiting the electricity generation substantially. Setup with low-strength wastewater produced a maximum CE (%) of 13.80. Overall results showed that although high-strength wastewater produced better and maximum power densities, medium and low-strength wastewater setups were more consistent in energy generation throughout the experiment.

Carrier transport and performance limit of semi-transparent photovoltaics: CuIn1−xGaxSe2 as a case study

Semi-transparent photovoltaic devices for building integrated applications have the potential to provide simultaneous power generation and natural light penetration. CuIn1−xGaxSe2 has been established as a mature technology for thin-film photovoltaics; however, its potential for Semi-Transparent Photovoltaics (STPV) is yet to be explored. In this paper, we present its carrier transport physics explaining the trend seen in recently published experiments. STPV requires deposition of films of only a few hundred nanometers to make them transparent and manifests several unique properties compared to a conventional thin-film solar cell. Our analysis shows that the short-circuit current, Jsc, is dominated by carriers generated in the depletion region, making it nearly independent of bulk and back-surface recombination. The bulk recombination, which limits the open-circuit voltage Voc, appears to be higher than usual and attributable to numerous grain boundaries. When the absorber layer is reduced below 500 nm, grain size reduces, resulting in more grain boundaries and higher resistance. This produces an inverse relationship between series resistance and absorber thickness. We also present a thickness-dependent model of shunt resistance showing its impact in these ultra-thin devices. For various scenarios of bulk and interface recombinations, shunt and series resistances, AVT, and composition of CuIn1−xGaxSe2, we project the efficiency limit, which—for most practical cases—is found to be ≤10% for AVT≥25%.

Revisiting the Analysis of Losses and Fuel Consumption in Synchronous Generating Units during the Production of Active and Reactive Energy

This article analyzes the losses, efficiency and fuel consumption of the generating units during the process of producing active and reactive energy. It presents a proposal for tests to determine the losses of the generating units already installed in the plants, proved by the actual application in a hydroelectric generating unit and in a thermoelectric generating unit. The result obtained in the study is a general equation of losses as a function of the simultaneous generation of active and reactive power that were determined through the variations of the armature and field currents and the terminal voltage of the generating unit, which can be represented by a three-dimensional graph showing total losses at all possible operating points. Losses have a direct influence on the efficiency of each component of the generating unit, directly influencing fuel consumption at the many allowable operating points. The study also showed the fuel consumption and loss curves in real hydroelectric and thermoelectric generating units installed in Brazil. With the determination of efficiency at each point of operation, it allows determining a weighting factor based on the value of the active and reactive energy generated, culminating in the proposition of an index that reflects the total production cost of each generator for an entire power plant. This makes it possible to divide the requested active and reactive energy in detail between less expensive generating units of the same hydro or thermal generating plant.

Microbial fuel cell enhanced pollutants removal in a solid-phase biological denitrification reactor: System performance, bioelectricity generation and microbial community analysis

A novel electrochemical system of microbial fuel cell (MFC) coupled solid-phase denitrification biofilm reactor (DBR) system was established to explore the effect of simultaneous power generation and pollutant removal under different HRTs (Ⅰ:48 h; Ⅱ :24 h). The average removal rates of methyl orange, Cr (VI) and NO3–-N in test group were 93.0, 98.6 and 95.5% within 60 days, while those were 53.1, 72.1 and 72.7% in control. The maximum power density was 61.2 (Ⅰ) and 16.1 mW/m2 (Ⅱ), while average output voltage was 122 (Ⅰ) and 83.6 mV (Ⅱ). Components 1 and 2 in soluble microbial products were identified, and the humic-like and fulvic acid-like substances varied through different layers. Pseudomonas produced electricity in anode, while denitrified in denitrification layer. Importantly, symbiotic cooperation was absolutely dominant in network analysis of both anodic and denitrifying biofilms. MFC significantly improved DBR's ability to treatment co-polluted wastewater.

Multi-objective optimization of a Concentrating Solar Power + Photovoltaic + Multi-Effect Distillation plant: Understanding the impact of the solar irradiation and the plant location

• The impact of the location parameters in a CSP + PV + MED is analyzed. • Multi-objective optimization is performed to minimize thermoeconomic costs. • The irradiation and distance have the most significant impact on the costs. • Cost maps of the thermoeconomic cost of electricity and water are presented. This research work presents the assessment of the impact of the solar irradiation, the distance from the coast, and the altitude of the location for a Concentrated Solar Power + Photovoltaic + Multi-Effect Distillation (CSP + PV + MED) plant for simultaneous power generation and seawater desalination. For that, a comparative analysis of the thermoeconomic cost of electricity and water (TCE and TCW) at different locations is carried out to determine the most competitive sites where this kind of cogeneration plant can be deployed. Also, multi-objective optimization is performed to assess the optimum sizing that allows reducing the costs. The study considers four Direct Normal Irradiation (DNI) levels (from 2000 to 3500 kWh/m 2 -yr), six distances from the sea (from 5 to 100 km), and six altitudes (from 20 to 1000 m.a.s.l.). The results show that solar irradiation has the most significant effect on the TCE and TCW, the distance to the sea affects the TCW considerably, and the altitude has a moderate impact despite its impact is substantially lower than the other two factors. Also, cost maps of the TCE and TCW giving insights about which locations have a higher potential for developing CSP + PV + MED plants are presented. From these maps, it has been found that the potential inland locations to reach TCE and TCW under 100 $/MWh and TCW 2 $/m 3 should have high DNI (at least 300 kWh/m 2 -yr above the coast level), distances from the coast up to 60 km, and altitudes up to 750–1000 m.

Developing an integrated hybrid polygeneration system combined with utility steam network

ABSTRACT In this study, an integrated hybrid polygeneration system based on solar and biogas energy is developed for simultaneous heat and power generation and hydrogen production. A heat recovery system is employed, which can recover the waste heat from the flue gas for effective utilisation in the steam network. The devised system, comprising solar, biogas, chemical, steam, and power islands, is investigated and comparatively evaluated through energy and exergy approaches. Additionally, an optimisation study is carried out to find the optimal exergy efficiency. The findings suggest that integrating the steam island and hybrid system improved the overall system performance significantly. The optimisation results demonstrate the value of 58.06% for exergy efficiency, while energy efficiency is also increased from 60.55% to 65.94%.

Microbial Fuel Cell for Energy Production, Nutrient Removal and Recovery from Wastewater: A Review

The world is facing serious threats from the depletion of non-renewable energy resources, freshwater shortages and food scarcity. As the world population grows, the demand for fresh water, energy, and food will increase, and the need for treating and recycling wastewater will rise. In the past decade, wastewater has been recognized as a resource as it primarily consists of water, energy-latent organics and nutrients. Microbial fuel cells (MFC) have attracted considerable attention due to their versatility in their applications in wastewater treatment, power generation, toxic pollutant removal, environmental monitoring sensors, and more. This article provides a review of MFC technologies applied to the removal and/or recovery of nutrients (such as P and N), organics (COD), and bioenergy (as electricity) from various wastewaters. This review aims to provide the current perspective on MFCs, focusing on the recent advancements in the areas of nutrient removal and/or recovery with simultaneous power generation.

Advancements in spontaneous microbial desalination technology for sustainable water purification and simultaneous power generation: A review

Population growth and rapid urbanization have put a lot of pressure on the already scarce freshwater around the globe. The availability of freshwater is not only limited but it is non-uniform also. Available desalination technologies help mitigate water shortage; however, these techniques are energy-intensive and unsustainable. Desalination technologies utilizing renewable energy and bio-electrochemical systems have been developed to achieve limited sustainability. With technological advancements, microbial desalination cell (MDC) has been developed which is capable of desalination, wastewater treatment, and power generation simultaneously. This review critically examined the performance of various MDC techniques concerning their stimulus parameters including COD removal, total desalination rate, total dissolved solids reduction rate, Coulombic efficiency, and power density. Limitations of MDCs have also been incorporated in the review. Work on MDC coupled with other robust desalination techniques offering advantages such as better desalination and more water recovery e.g. osmotic-MDC etc. has been included. Researchers have tremendously worked on MDCs with different electro-catalysts. Few of these are not sustainable and costly. Authors have reviewed critically with belief that it will pave a way for the commercialization of this eco-friendly technology.

Effect of cathodic culture on wastewater treatment and power generation in a photosynthetic sediment microbial fuel cell (SMFC): Canna indica v/s Chlorella vulgaris

The aim of this work was to compare the performance of the two types of photosynthetic microbial fuel cells (MFCs) fed with real wastewater- one having plant Canna indica (PMFC) and the other having alga Chlorella vulgaris (AMFC) at the cathode. The chemical oxygen demand (COD), phosphate, and nitrate removal stood at 57.16% 88.81%, 59.82% for PMFC and 65.27%, 95.59%, 66.61% for the AMFC. While AMFC was slightly superior in water treatment, the power output was 6 times higher in PMFC (22.76 mW m−2) than the AMFC (3.64 mW m−2). The biomass growth was good in both systems, with biomass productivity of 0.031 Kg m−3 day−1 in AMFC and a leaf area index of 0.006 in PMFC. The study's findings suggest that PMFCs are equally good or even better than AMFCs when the goal is simultaneous water treatment and power generation.

Integrated Coproduction of Power and Syngas from Natural Gas to Abate Greenhouse Gas Emissions without Economic Penalties.

Natural gas (NG)-fired power plants are significant greenhouse gas (GHG) emitters because of their substantial CO2 release. To avoid these emissions, precombustion and postcombustion CO2 capture alongside oxy-fuel combustion were considered in the literature. However, because of additional energy requirements, these options generally induce an approximately 7–10% decrease in net heat-to-power efficiencies regarding regular NG-air-fired stations without CO2 capture. To compensate for this declination, in this study, a simultaneous generation of power and syngas (CO and H2) was proposed in an integrated NG-oxygen-fired gas turbine unit (GTU). Hence, the combustion chamber in the NG-oxygen-fired gas turbine cycle was replaced by an NG partial oxidation reactor, which converts it into syngas. The syngas was separated from the working fluid of the cycle by the condensation of water vapor (steam), and a part of it was withdrawn from the GTU to be utilized as a chemical feedstock. A benchmark thermodynamic analysis at the same input–output conditions and requirements for carbon capture was conducted to compare the proposed unit with NG-air and NG-oxygen-fired power plants. The integration effect was shown by increasing the heat-to-power efficiency from 48 to 54%. With carbon monoxide (CO) as an intermediate, the author proposed capturing carbon in NG (methane) in liquid formic acid, which is a good commodity for transportation to a place where it can be reconverted into CO or H2 to manufacture various industrial chemicals. Simple economic considerations show that because of a substantially higher cost of formic acid than an equivalent power, CO conversion into formic acid substantiates the integrated approach as economically attractive.