Clean Power Generation Technology Research Articles

Bio-inspired polyionic membrane for long-lasting and repeatable electricity harvesting from moisture

Evaporation power generation (EPG), hailed as a promising clean power generation technology, has garnered significant attention. Nonetheless, achieving consistent and replicable performance of EPG remains a major challenge, hampering its practical application potential. Herein, we present the design of a tri-layered poly-ionic membrane (TL-PIM) inspired by transpiration processes in plants, that can not only continuously output electricity with an average voltage of ∼0.6 V for over 8 consecutive days with a maximum power density of 1.6 µW cm−2, but can also be reused for at least 70 cycles (> 350 h) with a stable voltage, demonstrating superior repeatability over most previous works. The excellent long-lasting and repeatable performance of EPG in the TL-PIM can be attributed to the stable nanochannels constructed by a hydrophilic polymer, 2D nanosheets, and poly-ionic liquids (PILs), where the bromide ions (Br-) in the PILs can shuttle back and forth selectively and efficiently during the power generation and discharge processes. More importantly, the TL-PIM can be integrated linearly to generate electricity within a wide range of temperatures and humidity, even outdoors, showcasing remarkable environmental adaptability. These findings on EPG indicate that the bio-inspired TL-PIM offers a promising venue for continuous and reproducible electricity generation by harnessing thermal energy from moisture, which holds significance for the sustainable utilization of EPG as a renewable energy source in the future.

Effect of steam reinjection mass flow rate on the SOFC–GT system with steam reinjection

A solid oxide fuel cell (SOFC) is regarded as the first choice of high-efficiency and clean power generation technology in the 21st century due to its characteristics of high power generation efficiency and low pollutant emission. In this paper, hydrogen is used as a fuel for SOFCs using the EBSILON platform. A sensitivity analysis of the solid oxide fuel cell–gas turbine (SOFC–GT) system with steam reinjection is carried out to investigate the effect of the steam reinjection mass flow rate on the improvement of the electrical efficiency of the system and on the values of the other parameters. The results show that the variation in the steam reinjection mass flow rate has an effect on other parameters. Changes in several parameters affect the electrical efficiency of the system, which reaches 74.11% at a pressure ratio of 10, SOFC inlet temperature of 783.15 K, turbine back pressure of 70 kPa, and steam reinjection mass flow rate of 6.16 kg/s. Future research can optimize the overall parameter selection of the system in terms of economy and other aspects.

Numerical analysis of natural gas, hydrogen and ammonia fueled solid oxide fuel cell based micro cogeneration units with anodic gas recirculation

The energy sector is actively transitioning towards climate-neutral solutions, emphasizing advancements in clean power generation technologies. Cogeneration systems based on solid oxide fuel cells (SOFC) currently exhibit higher electrical efficiencies than conventional plants, but their operation can still be improved. One of the approaches to increase its efficiency is implementing anodic off-gas recirculation. In this work, a numerical model of a 10 kW SOFC installation with anodic gas recirculation was analyzed using Aspen HYSYS software. System fueled with three alternative fuels (natural gas, hydrogen, and ammonia) was tested. In this paper it was proven that anode-off gas recirculation improves the electrical and total efficiency of the system for each fuel type. The cogeneration unit with a SOFC stack can operate safely over a wide range of recirculation ratios without need for additional modifications. Ammonia-fueled units achieve electrical efficiency (55%) higher than hydrogen-based system (47.6%) but lower than installation fueled with natural gas (61.8%).

Advanced Cathode Materials for Protonic Ceramic Fuel Cells: Recent Progress and Future Perspectives (Adv. Energy Mater. 34/2022)

Protonic Ceramic Fuel Cells Protonic ceramic fuel cells (PCFCs) working at an intermediate temperature range have been emerging as a promising clean power generation technology. In article number 2201882, Lei Du, Baoyin Yuan, Siyu Ye and co-workers present a comprehensive review on advanced cathode materials with tailorable H+, O2−, and e− conductivities for PCFCs. The relevant perspectives are expected to be helpful for future PCFCs R&D.

Kinetics and Mechanism of Nickel Oxide Reduction by Methane

Nickel oxide reduction by methane is of particular importance in catalysis, extractive metallurgy, and clean power generation technologies. Despite extensive investigations of the NiO + CH4 reaction, many questions remain about its kinetics and molecular and structural transformation mechanisms. This work reports the reduction kinetics of bulk polycrystalline NiO by CH4 using a new calorimetric method. The method permits rapid, controllable heating of the NiO/Ni wires and continuous data (electrical power, the electrical resistivity of the wire, and temperature) acquisition with a frequency of 10 kHz. The method also allows arresting and preservation of the structure of the sample by programmed termination of electric power in thin specimens. This approach, coupled with ex situ electron microscopy, allows determination of the reaction rate and tracking of the ongoing structural transformations. The mechanism of NiO reduction by methane is suggested based on direct correlations between reaction kinetics an...

The Influence of Directing Environmental Policies on the Technology Selection and TFP of Chinese Power Generation Companies

This paper considers the 2005 Renewable Energy Law in China as a natural experiment and investigate the influence of this policy on the clean power generation technology by difference-in-difference method. It finds that:firstly, the Renewable Energy Law and its related policies promote the use of clean technology and improve the productivity of power companies. The production capacity and total factor productivity(TFP) of clean power generating plants increase by 8% and 10% respectively, compared to traditional power generating plants. Secondly, the policy effects reinforce over time. Thirdly, power companies that receive subsidies tend to invest more on research and development(R&D) and achieve more significant TFP improvements. Thus the renewable energy policy promotes the clean technology bias of power generation industry. The conclusions of this paper can judge the role of public policy in changing the bias of environment technology, and can provide theory basis for the corresponding environment policy.

Pressure retarded osmosis in closed circuit: a new technology for clean power generation without need of energy recovery

Power generation from salinity gradients by means of Pressure Retarded Osmosis (PRO) is currently preformed by conventional methods, wherein Energy Recovery (ER) is an essential feature without which such a process is impossible. The newly conceived Closed Circuit (CC) Pressure Retarded Osmosis technology (CC-PRO) described herein is based on a continuous consecutive sequential batch process; wherein, pressurized high salinity feed (HSF) is continuously supplied to the inlets of PRO modules and pressurized effluent removed from their outlets through internal circulation means by the alternating engagement/disengagement of two side conduits (SC). This process proceeds with high energy conservation without need of ER means. The new CC-PRO technology enables high operational flexibility achieved by set point selection of the permeation flux; the circulation flow; the applied pressure of power generation; and the flow ratio circulation/permeation which defines the salinity and osmotic pressure gradients inside the PRO modules. The high flexibility is manifested by the availability of an infinite number of set point combinations for the optimization of the process with respect to maximum power production under lower membrane detrimental effects and reduced fouling factors.

Influence of the oxidation step on the behaviour and the performances of an oxygen carrier in fixed bed reactor

Chemical Looping Combustion is a promising technology for clean power generation with integrated CO2 capture. In this process the oxygen required for combustion is provided by a metal oxide. This work deals with the development of an experimental procedure to study performances of an oxygen carrier during oxidation/reduction cycles and the influence of the oxidation step on its behaviour. Tests were performed in a laboratory fixed bed reactor, with NiO/NiAl2O4, a promising oxygen carrier, and CO as fuel. Two different protocols of oxidation were studied. Results reveal that the oxidation step conditions can change the performances of the oxygen carrier. A significant decrease in total reduction capacity was observed using the regeneration step at high temperature due to structural changes in particles. SEM analysis reveals that particle surface contains different crystallites according to this procedure. With the second procedure (oxidation in temperature ramp), nickel is partially agglomerated.

Development of a novel 2-stage entrained flow coal dry powder gasifier

Coal-fired gasifiers are the key technology for clean power generation and coal chemical process. This paper presents a 2-stage entrained flow dry powder gasifier in which coal is entrained into the lower chamber burner with oxygen and steam to raise the temperature of the crude gas up to 1700°C. The lower chamber is linked to the upper gasification chamber through a middle throat, where additional coal and steam is fed to cool down the slag to less than 900°C for deslagging from the lower chamber bottom.Various coals have been characterized and gasified with this 2-stage entrained flow dry powder gasifier and comparisons made with single stage gasifiers. The results show that the 2-stage gasifier is suitable for a broad range of coal varieties and gives carbon conversion up to 98.9% with cold syngas efficiency of 83.2% at a pressure of 3.0MPa, while the oxygen and coal consumption are lower than with the single stage gasifier.

Visualization of Temperature Distribution and Clarification of Heat and Mass Transfer Mechanism in a Single Cell of PEFC

Polymer electrolyte fuel cell (PEFC) has been developing as clean power generation technology. However, there are some subjects to spread PEFC among industries and homes in the world. The one of such subjects is drop in power generation performance and durability caused by heat and mass distribution in a single cell of PEFC. The purpose of this study is to point out the dominant factor of heat and mass transfer phenomena and clarify the reason for heat and mass distribution in a single cell. With the aid of observation window, the in-plane temperature distribution in single cell under power generation was measured by thermograph. The influence of operation conditions on temperature distribution was investigated. Moreover, to clarify the heat and mass transfer mechanism theoretically, the simulations to investigate the factor needed for the ideal reaction and evaluate the influence of separator structure on heat and mass distribution were carried out.

CRITICAL ANALYSIS OF IMPACT OF ELECTRIC POWER GENERATION ON GREENHOUSE GAS EMISSIONS IN EUROPE

The article makes a critical analysis of the impact electric power generation has on greenhouse gas emissions in Europe with reference to the Kyoto protocol. First, a possible Italian strategy for implementing Kyoto protocol mechanisms to meet commitments of the EU Emission Trading Draft Directive, the Italian strategy in the Ministerial documents and final considerations are analysed. Then measures to limit greenhouse gas emissions in Greece, a country whose economy is anticipated to converge to the average European economy, are considered. Here, impact of the currently adopted measures and initiatives to reduce emissions in the Greek energy system for the period up to 2030 are discussed, with emphasis on the current decade. Also examined is how the UK is dealing with greenhouse gas emissions in respect of the Kyoto protocol. Clean power generation technology for the 21st Century is then examined. This gives a perspective from the EU Power Plant Supply Industry. A perspective is presented with respect to impact of global climate change (GCC) on product development strategy. Such environmental drivers, typified by the increasing public and political desire to introduce measures that will reduce greenhouse gas (GHG) (especially C0 2 ) world-wide have to be positioned against the other key market issues of wider globalization, increased liberalization, deregulation and privatization, all of which contribute to the substantial changes in the energy market world-wide.

Impact of electric power generation on green house gas emissions in Europe: Russia, Greece, Italy and views of the EU power plant supply industry – A critical analysis

This paper analyses the impact of electric power generation on greenhouse gas emissions in Europe (including the Asian part of Russia) with reference to Russia, Greece, Italy, and views of the EU power plant supply industry in respect of the Kyoto protocol. The outlook of power industry development in Russia in the 21st century is first considered and its impact on Russia’s greenhouse gas emissions is examined. Forecasts for developing Russia’s economy and electric power industry in the first half of the 21st century are presented. Possible structural change in the electric power industry in Russia together with dynamic changes of CO 2 emissions from fuel combustion in power plants are examined. It is shown that CO 2 emissions from fuel combustion at power plants in Russia may increase 2.7-fold in 50 years. Calculations depict that specific CO 2 emissions in Asian Russia exceed greatly that of the European part. It then reviews measures to limit greenhouse gas emissions in Greece. Impact of the currently adopted measures and initiatives to reduce emissions in the Greek energy system for the period up to 2030 is discussed with emphasis on the current decade. Under the scenario for environmental policy, the additional commitments and measures to limit CO 2 emissions towards the Kyoto targets are discussed. The paper summarizes a possible Italian strategy for implementing Kyoto protocol mechanisms to meet commitments of the EU Emission Trading Draft Directive, the Italian strategy in the Ministerial documents, and final considerations. It then examines clean power generation technology for the 21st Century and gives a perspective from the EU power plant supply industry. A perspective is presented with respect to impact of global climate change on product development strategy. Fossil fuel based power generation technologies will continue to play an important part of the energy mix in the foreseeable future and different parts of the world will require different technologies to meet their local specific requirements. It will be necessary to continue to develop clean technologies and to promote their use world-wide.