Role In Renewable Energy Technologies Research Articles

Carbon-based electrocatalyst derived from bimetallic metal-organic framework arrays for high performance oxygen reduction

Electrocatalysts for oxygen reduction reaction (ORR) play a key role in renewable energy technologies including metal-air batteries and fuel cells. Despite tremendous efforts, the development of ORR electrocatalysts with high activity and low cost remains a great challenge. Here, we report the fabrication of well-defined carbon network with honeycomb-like structure as a high-performance catalyst toward ORR, via pyrolysis of bimetallic Co, Zn-zeolitic imidazolate (Co, Zn-ZIF) crystal arrays grown on the surface of layered double hydroxide nanoplatelets (LDHs@Co, Zn-ZIF). The concentration of doped-heteroatoms (N, Co), the graphitic degree as well as the surface porosity of the resulting carbon network can be finely controlled by tuning the Co/Zn molar ratio in the LDHs@Co, Zn-ZIF precursors. The optimal carbon catalyst (CoZn-2) exhibits excellent ORR activity with an onset potential of 0.976V vs. RHE and a limited current density of 5.8mAcm−2, which is superior to commercial Pt/C catalyst. In addition, both an extraordinary long-term stability (∼99.5% current retention over 20,000s) and a strong tolerance against methanol corrosion are also obtained. This work demonstrates an effective strategy to artificially regulate the nanostructure and intrinsic active site of carbon-based ORR electrocatalysts.

Hierarchical MnO2/rGO hybrid nanosheets as an efficient electrocatalyst for the oxygen reduction reaction

Electrocatalysts for the oxygen reduction reaction (ORR) play a crucial role in renewable-energy technologies, including metal-air batteries and fuel cells. However, development of novel catalysts with high activity and low cost remains a great challenge. Here, we present hierarchical MnO2/reduced graphene oxide (MnO2/rGO) hybrid nanosheets by using a facile method and study its electrocatalytic performance. Cyclic voltammograms, and rotating disk electrode and rotating ring/disk electrode measurements demonstrate that the hierarchical MnO2/rGO hybrid nanosheets exhibit excellent electrocatalytic activity for the ORR in an alkaline medium, as evidenced by their higher cathodic current density, more positive onset potential, lower H2O2 yield, and higher electron transfer number compared to pure rGO. The excellent catalytic activity of the MnO2/rGO hybrid nanosheets highlights the importance of the synergetic chemical coupling effect between the ultrathin MnO2 nanosheets and the graphene layer.

Heteroatom-Doped Graphitic Carbon Catalysts for Efficient Electrocatalysis of Oxygen Reduction Reaction

The oxygen reduction reaction (ORR) plays an important role in renewable energy technologies, such as fuel cells and metal–air batteries. Along with the extensive research and development of nonprecious metal catalysts (NPMCs) to reduce/replace Pt for electrocatalytic reduction of oxygen, a new class of heteroatom-doped metal-free carbon catalysts has been recently developed, which, as alternative ORR catalysts, could dramatically reduce the cost and increase the efficiency of fuel cells and metal–air batteries. The improved catalytic performance of heteroatom-doped carbon ORR catalysts has been attributed to the doping-induced charge redistribution around the heteroatom dopants, which lowered the ORR potential and changed the O2 chemisorption mode to effectively weaken the O–O bonding, facilitating ORR at the heteroatom-doped carbon electrodes. Subsequently, this new metal-free ORR mechanism was confirmed by numerous studies, and the same principle has been applied to the development of various other eff...

Mo-V-O Based Electrocatalysts for Low Temperature Alcohol Oxidation

There is a growing interest in alcohol oxidation electrochemistry due to its role in renewable energy technologies. The goal of this work was to develop active non- precious metal electrocatalysts based on the Mo-V-(M)-O (M is Nb, Te) lattice. Selective gaseous alkane oxidation had been previously observed on these catalysts at elevated temperatures above 300 °C. In this study, the activity of the catalysts at lower temperatures, 25–60 °C, was investigated. Hydrothermal conditions were used to synthesize the Mo-V-(M)-O mixed oxides. Physical characterization of the catalysts were obtained by powder X-ray diffraction (XRD), scanning electron micrography (SEM) equipped with energy dispersive X-ray (EDX), transmission electron micrography (TEM), and X-ray photoelectron spectroscopy (XPS). The catalytic activity for the oxidation of cyclohexanol was studied electrochemically. Chronoamperometric studies were used to evaluate the long-term performance of the catalysts. The onset of alcohol oxidative current was...

Bacterial recovery and recycling of tellurium from tellurium-containing compounds by Pseudoalteromonas sp. EPR3.

Tellurium-based devices, such as photovoltaic (PV) modules and thermoelectric generators, are expected to play an increasing role in renewable energy technologies. Tellurium, however, is one of the scarcest elements in the earth's crust, and current production and recycling methods are inefficient and use toxic chemicals. This study demonstrates an alternative, bacterially mediated tellurium recovery process. We show that the hydrothermal vent microbe Pseudoalteromonas sp. strain EPR3 can convert tellurium from a wide variety of compounds, industrial sources and devices into metallic tellurium and a gaseous tellurium species. These compounds include metallic tellurium (Te(0)), tellurite (TeO3(2-)), copper autoclave slime, tellurium dioxide (TeO2), tellurium-based PV material (cadmium telluride, CdTe) and tellurium-based thermoelectric material (bismuth telluride, Bi2Te3). Experimentally, this was achieved by incubating these tellurium sources with the EPR3 in both solid and liquid media. Despite the fact that many of these tellurium compounds are considered insoluble in aqueous solution, they can nonetheless be transformed by EPR3, suggesting the existence of a steady state soluble tellurium concentration during tellurium transformation. These experiments provide insights into the processes of tellurium precipitation and volatilization by bacteria, and their implications on tellurium production and recycling.

Role of renewable energy technologies in rural communities' adaptation to climate change in Nepal

The aim of this paper is to analyze the role of renewable energy technologies (RETs) such as biogas, improved cooking stoves (ICSs), micro hydro (MH) and solar power (SP) in helping rural communities in Nepal to adapt to climate change. The analysis considers the energy efficiency of different RETs as well as their socio-economic and environmental impacts. The efficient use of biomass in new technology, such as biogas and ICSs for cooking, has increased energy security and reduced the negative effects of traditional biomass usage. MH and SP systems are replacing candles and kerosene lamps, and are the most promising RET models for electricity generation in rural Nepal. The improved illumination from these technologies also produces better education, health, environments, and social harmony in rural communities. This study uses the Long-range Energy Alternatives Planning model (LEAP) model to develop a plan for long-term RETs use in Nepal, and specifically focuses on household energy use in rural areas. It assesses the role of biogas and ICSs in rural communities and climate change adaptation in Nepal, along with the potential role of MH and SP technologies. According to the LEAP analysis, the planned implementation of MH for 20-year long-term will result in the reduction of 2.553 million tons of CO2 emissions. Similarly SP, biogas, and ICSs will result in a reduction in CO2 emissions of 5.214 million tons, 35.880 million tons, and 7.452 million tons, respectively.

Role of Renewable Energy Technologies for Rural Electrification in Achieving the Millennium Development Goals (MDGs) in Nepal

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Mutual Dependence between Sustainable Energy- and Sustainable Agriculture Policies-from the Global and European Perspective

The aim of the paper is to present the interrelationship between the sustainable energy, especially renewable energy sector and sustainable agriculture policy from both: the European and the global perspectives. In the world and European economy the role of Renewable Energy Technologies is still increasing. Energy efficiency; sustainable agriculture; renewable energies for rural development belong to main poles of sustainable development in the world economy and its regions. Agriculture is one of the economic sectors to which the EU commitment to reduce emissions of greenhouse gases applies. Like any other economic sector, agriculture produces greenhouse gases and is a major source of the non- CO2 greenhouse gases methane and nitrous oxide. It is also the strong relationship between the sustainable agriculture sector and the renewable energy development possibilities. The sustainable agriculture can be seen as a source of renewable energy.

An effective electrocatalyst for ethanol oxidation: Pt-modified IrCu alloy nanoparticle

There is a growing interest in ethanol oxidation electrochemistry as it plays an important role in renewable energy technologies. The goal of this work was to develop active multifunctional catalyst materials for ethanol oxidation. Here, a carbon-supported Pt-modified IrCu alloy electrocatalyst (Pt–IrCu/C) was prepared by a two-step method. X-ray diffraction and transmission electron microscope showed that the Pt–IrCu/C has a two-phase structure: Pt nanoparticle-modified IrCu alloy. The Pt–IrCu/C catalyst was found to have not only a large electrochemically active specific area (S EAS) but also good CO oxidation ability for oxidation of ethanol compared to the commercial Pt/C electrocatalyst using cyclic voltammetry. Furthermore, the Pt current density of Pt–IrCu/C was more than 1.6 times as high as that of Pt/C for ethanol oxidation. The Pt–IrCu/C catalyst also exhibited more efficient usage of Pt and enhanced the stability of ethanol electro-oxidation compared with a Pt/C catalyst.

Forecasting of electricity costs based on an enhanced gray-based learning model: A case study of renewable energy in Taiwan

This work presents a novel gray-based cost efficiency (GCE) model that integrates the gray forecasting model into a two-factor cost efficiency curve model for renewable energy (RE) technologies and identifies the optimal forecasting model for power generation cost of RE technologies. The analytical framework of proposed GCE model improves short-term prediction of power generation cost, and can be applied during the early developmental stages for RE technologies. Empirical analysis is based on wind power data for Taiwan. Time lag of knowledge stock was simulated to represent the actual relationship between R&D expenditures and cost reductions in power generation by knowledge stock. Analytical results demonstrate the GCE model is a useful tool to quantify the influences of cost reductions in power generation. The implications of analytical results are that institutional policy instruments play an important role in RE technologies achieving cost reductions and market adoption. The proposed GCE model can be applied to all high-technology cases, and particularly to RE technologies. The study concludes by outlining the limitations of the proposed GCE model and directions for further research.

A methodology for the electrical energy system planning of Tamil Nadu state (India)

In this paper, an energy planning optimisation procedure of a selected territory is illustrated and applied using an energy flow optimisation model. The developed approach takes into account various electricity generating options to meet the energy needs of various demand sectors. Energy saving techniques and hybrid technologies are considered and various scenarios are developed by assessing the contribution of renewable energy technologies over the planning period. The procedure aims to reduce the total actualised cost of energy generation over selected time horizon and predicts the additional installations required along with the existing facilities to meet the energy demand. At the same time the role of renewable energy technologies and of energy saving measures is evaluated by imposing suitable constraints on CO 2 emissions and primary energy sources exploitation. The procedure is applied to the territory of Tamil Nadu state (India) by considering different energy planning scenarios.

Analysis of Renewable Energy Situation in Jordan

Jordan, like most developing countries, has problems, constraints, and difficulties that mandate increasing renewable energy (RE) technology utilization. The most effective argument in favor of the adoption of RE technologies in Jordan is that its lack of conventional energy sources is complemented by abundant RE resources. Because RE technologies are not complex, require less operating and maintenance costs and are inherently more environmentally benign than conventional energy sources foster their consideration by energy policy makers as essential components of the national energy balance. The most prudent approach to address this strategic issue is to alleviate the problems, constrains, and difficulties associated with each of the above-mentioned influencing factors. This paper analyzes the current energy situation in Jordan, and discuses the importance of increasing the role of RE technologies in the energy mix. It also discusses some success stories in the RE technologies domain, analyzes the barriers affecting their development, and suggests future courses of action in order to attain their maximum utilization potential. It is believed that this paper will benefit energy policy makers in Jordan, as well as in other developing countries.

04/01448 Power sector reform in small island developing states: what role for renewable energy technologies?: Weisser, D. Renewable and Sustainable Energy Reviews, 2004, 8, (2), 101–127

04/01448 Power sector reform in small island developing states: what role for renewable energy technologies?: Weisser, D. Renewable and Sustainable Energy Reviews, 2004, 8, (2), 101–127

04/00793 On the economics of electricity consumption in small island developing states: a role for renewable energy technologies?: Weisser, D. Energy Policy, 2004, 32, (1), 127–140

04/00793 On the economics of electricity consumption in small island developing states: a role for renewable energy technologies?: Weisser, D. Energy Policy, 2004, 32, (1), 127–140

An analysis of Grenada's power sector and energy resources: a role for renewable energy technologies?

Presently, Grenada's power sector is fully dependent on fossil fuel imports for meeting the country's electricity demand. Electric utilities in Small Island Developing States (SIDS), in general, face high cost of electricity generation due to diseconomies of scale in production, consumption and logistical aspects. Grenada's private power monopoly is no exception and the high cost of import dependent electricity generation places an increasing burden on economic development. In light of rapid technological and economic improvement of renewable energy technologies (RETs), the country's abundant sources of renewable energy should be harnessed. Benefits are envisaged to include lower electricity cost, better environmental performance and a safer and diversified supply of energy. However, barriers for shifting power production towards meaningful contributions from RETs exist, both in government and industry. This work analyses important economic interactions between the power sector and economic development, bringing to attention the importance of power sector reform. Further, present problems of integrating RETs into the grid, ranging from technical and regulatory issues to shareholder interest are investigated. A summary and analysis of past research into renewable sources of energy (RES) underscore the potential for power production from RETs in Grenada.

On the economics of electricity consumption in small island developing states: a role for renewable energy technologies?

This paper reviews the economic implications of power production in small island developing states (SIDS). To date electricity generation is primarily based on fossil fuels creating serious economic and financial difficulties. It is argued that renewable energy technologies (RETs) have the potential to undercut the cost of current modes of electricity generation. This is primarily due to an abundance of renewable energy resources and characteristics specific to SIDS that make fossil-fuel-based electricity production extremely expensive. However, this requires a change not only of energy policies but also of scope and structure of electricity planning. So far energy policies aiming to promote RETs on SIDS have neglected to study the immediate and future technological feasibility of such programmes. However, this has serious implications on the cost of electricity supply systems and need to be considered alongside the dynamics of energy markets to allow capturing economic risks and benefits also in the long term.

Linking national-level and village-level energy planning in developing countries

The nature of current energy planning methods used in the developing countries of the world is examined. Such planning is usually carried out at two poorly coupled levels, the national level and the village level. The nature of the planning at both levels is explored, with particular reference to the role of renewable energy technologies. The problem of productive interaction between the two levels is posed, and a solution is examined in terms of a cadre of energy advisors.