Renewable Energy Options Research Articles

Development of a design and implementation process for the integration of hydrokinetic devices into existing infrastructure in South Africa

In South Africa there is currently no notable use of modern small-scale hydrokinetic (HK) energy systems, mainly due to formerly low-cost coal-powered electricity. This renewable energy option makes use of the kinetic energy from flowing water, rather than potential energy, which is more often used in conventional hydropower. Updated refined versions of this technology are now being investigated and manufactured due to the global drive towards reducing carbon emissions and increasing energy efficiency. These modular units allow for installation of HK turbines into existing water infrastructure with very little civil works. The study’s objective was to develop a simplified design and implementation process for HK devices within the South African legislative and regulatory environment. Approximately 66% of South Africa’s water supply is used by the agricultural sector with more than 6 500 km of canal systems running through many areas which could benefit from alternative energy sources. The recent electricity crisis in the country allowed for problem resolution through funding opportunities and thereby an introduction of an innovative and sustainable technology to provide renewable electricity where otherwise not feasible. A pilot HK project was implemented in an applicable section on the Boegoeberg irrigation canal in the Northern Cape Province and tested for optimum functionality and correct application. This process allowed evolution of a development process for the implementation of HK devices in existing water infrastructure.

Highly active M2P2O7@NC (M = Co and Zn) for bifunctional electrocatalysts for ORR and HER

Tuning the coordination environment between metal centers and organic ligands is a promising way to design of the precursors of electrocatalysts for water splitting or other renewable energy options. In this work, a novel coordinated polymer was prepared feasibly in polyvinyl pyrrolidone (PVP) aqueous solution using aminotrimethylene phosphonic acid (ATMP, L1) and 2-methylimidazole (MeMI, L2) as ligands with the ratio of 2:5, Co2+ and Zn2+ as metal centers. Based on the concept of acid-base neutralization reaction, the proton-transfer induced “deprotonation and protonation” for L1 and L2, respectively. Thus, the coordination was dominated by the deprotonated L1. Owing to also partial of protonated L2 adsorbed as “counter ions”, carbonization of the obtained precursor at 800 °C under N2 atmosphere endows the pyrolysis product with nitrogen-doped carbon supported metal pyrophosphate (M2P2O7@NC). Thus, the resulting M2P2O7@NC exhibits the enhanced and durable ORR and HER performance. For ORR in 0.1 M KOH, an enhanced onset potential (0.925 V vs. RHE), half wave potential (0.793 V vs. RHE) and diffusion limiting current (6.132 mA cm−2) can be obtained comparable to those of Pt/C. For HER in 0.5 M H2SO4, it only needs an over potential of 180 mV to realize a current density of 10 mA cm−2.

ENERGY RECOVERY FROM ANIMAL MANURE: BIOGAS POTENTIAL OF BURDUR, TURKEY

Sustainable development depends on the availability of energy resources and their impact on environment. Biogas is a carbon neutral renewable energy option and one of the leading solutions to the climate change combat. As Turkey is an energy importer country, using indigenous energy sources is vital to meet future energy demand. Agricultural activities and livestock potential have important economic value in Turkey. Biogas production from organic wastes such as livestock manure in this context, gain more importance to contribute both renewable energy production and waste management strategies. Livestock farming has high economic value in Burdur. In this regard, the animal manure based biogas potential, energy value, electricity and organic fertilizer generation capacity of Burdur Province is determined in this study. The results revealed that Burdur has annually 1.45 million tons of available animal manure potential to be used for biogas production of 27.1 million m3/year. This potential corresponds to 11641 TOE and 135.4 GWh annual energy generation that could be converted to heat and electricity. Considerable amount of the biogas production capacity has accumulated in Center, Bucak, Yesilova, Golhisar and Karamanli districts of Burdur. In addition, 50776.1 tons/year of organic fertilizer can be produced as the residual of the biogas plants.

Integrated assessment projections for global geothermal energy use

The use of geothermal energy is expected to grow rapidly over the next several decades at many places in the world, since geothermal resources are abundant, and because this renewable energy option is both a low-carbon and non-intermittent technology. With the integrated assessment model TIAM-ECN we quantify how large its growth could be until 2050, and analyze how this expansion could be stimulated by both climate policy and technological progress. We inspect both geothermal energy’s main applications: the generation of electricity and the production of heat. For the former, we project an increase to a power production level of around 800–1300 TWh/yr in 2050, depending on assumptions regarding climate ambition and cost reductions for enhanced geothermal resource systems. For the latter, with an emphasis on residential and commercial heat use applications, we anticipate under the same assumptions a rise to about 3300–3800 TWh/yr in the same year. We estimate that by 2050 geothermal energy plants, partly in competition with renewables like solar and wind power, as well as with incumbent fossil fuel based power production, could contribute approximately 2–3% to global electricity generation. If all nations stay on track of the Paris Agreement target by not increasing the global average atmospheric temperature with more than 2°C, and if the costs of geothermal energy production from deep formations reduce with the same learning rate of 13% that has been empirically observed for fracking technology applied to natural gas fields, we project a possible total geothermal energy investment market (supply plus demand side) worth about 500 billion US$/yr by mid-century.

Lightning protection design of solar photovoltaic systems: Methodology and guidelines

Solar photovoltaic (PV) system is one of the promising renewable energy options for substituting the conventional energy. PV systems are subject to lightning damage as they are often installed in unsheltered areas, and have vulnerable electronic devices. This paper proposes a partial element equivalent circuit (PEEC) method enhanced with the vector fitting technique for analyzing lightning transients in the PV systems. The frequency-dependent effects and ferromagnetic properties of structural steel are taken into account. Models of major components in the PV systems including structure steels, wiring in panels, and PV cells are provided. The non-linear surge protective device (SPD) is also considered in the modelling. An experiment on a PV panel is presented for the validation of the proposed method. The proposed procedure is finally applied to investigate lightning transients in a practical PV system. The lightning failure mode of bypass diodes is identified for the first time. The results can help to design effective lightning protection and select appropriate parameters of protective devices.

Development of a Conductive Biomimetic Nanocomposite Anode for Improved Microbial Fuel Cell Efficiency

Microbial fuel cells (MFCs) have gained attention as a renewable energy option due to the utilization of microbes as catalysts for the oxidation of natural substrates. In order to increase the practical application of MFC technology, the overall system must enhance power output and lower operational costs. More specifically, the bacteria must dock on the electrode surface to allow for efficient electron transfer mechanisms. In efforts to increase productive bacteria-surface interactions, this work focuses on the synthesis of a conductive, cellulose-based nanocomposite for use as anodic electrodes. The nanocomposite material was non-covalently modified through the incorporation of sugar-functionalized TiO2 nanoparticles. The relationship between conductivity and biocompatibility was explored in order to optimize the interactions between the synthesized electrodes and Escherichia coli (E. Coli). Power production using the composite electrodes was correlated to biofilm formation and cell proliferation via atomic force microscopy (AFM) and live/dead stain, respectively. The composite electrode materials have shown increased electrical response over traditional carbon cloth when used as anodes under dye-mediated conditions. Additionally, the sugar-functionalized composites showed increased bacterial adsorption and enhanced cell viability indicating more intimate contact between the microbes and the electrode surface. Initial results also suggest photochemical activity using sugar, polyaniline modified TiO2 nanoparticles embedded within the cellulose matrix resulting in responsive fuel cell behavior. Future work aims to incorporate supramolecular structures, such as β-cyclodextrin, to constrain dye absorption to the material surface and potentially increase the electrical response and longevity of the fuel cell system.

Review of Design Trends in Lighting, Environmental Controls, Carbon Dioxide Supplementation, Passive Design, and Renewable Energy Systems for Agricultural Greenhouses

The purpose of this article is to present a comprehensive overview of the latest developments in greenhouse design to find the leading design practices that lower the carbon and energy footprint. This paper is based on a comprehensive review of existing literature regarding design trends in lighting, environmental controls, carbon dioxide supplementation, passive design features, and renewable energy for agricultural greenhouses. A systematic review of existing literature on the design trends in lighting, environmental controls, carbon dioxide supplementation, passive design features, and renewable energy options for agricultural greenhouses has been presented. This systematic review provides a platform for universal greenhouse design guidelines to help promote urban agriculture and ensure food security for cities.

Solar Energy Development in Pakistan: Barriers and Policy Recommendations

Energy generation is heavily dependent on fossil fuels in Pakistan. Due to the huge population and current progress in industrialization, these sources are not fulfilling the existing energy needs of the country. Meanwhile, they have adverse environmental impacts and are economically unsuitable to electrify remote areas. Consequently, there is a need to look for alternate energy sources. The aim of this paper is to find out the best renewable energy option for Pakistan. For this purpose, we have collected data for solar radiation and wind speed for a period of one year in four major cities of Pakistan. Results indicate that solar energy is the best renewable energy option for Pakistan in terms of price, life span, operation and maintenance cost. Key barriers have been identified over the whole solar energy spectrum through semi-structured interviews with industry professionals. And finally, important policy recommendations have been proposed for institutions and government to overcome these barriers and utilize maximum solar energy in the country.

Visitors’ preferences of renewable energy options in “green” hotels

Tourism belongs to the industries with significant energy consumption. Visitors as well as hotel managers have, however, a positive attitude towards the responsible use of energy resources. The level of research on visitors’ preferences of using different types of renewable energy is low, unlike findings on factual characteristics of conventional and renewable energies. That is why our aim was to assess visitors’ preferences of environmentally friendly energy sources in hotels. Preferences of six types of renewable energy - “green” tariff energy, solar panels on the rooftops, solar panels on the ground, heat pumps, AD, wind turbine, were measured at four tourist destinations in the Czech Republic. The positive attitude of tourists towards the selected types of energy sources was confirmed. The highest preferences were found for solar panels installed on the rooftops. A typology of preferences was revealed by cluster analysis and differences between clusters were tested for independent variables. Clusters of visitors with a high and low interest in any type of renewable energy were identified as well as a cluster of visitors with interest in all types apart from solar panels installed on the ground - the visitor’s origin was found as the main differentiation factor.

Journey towards Renewable Energy for Sustainable Development at the Local Government Level: The Case of Hessequa Municipality in South Africa

The purpose of the research on which this article reports was to investigate how renewable energy forms part of the strategy of a local government, and to evaluate how participatory processes are utilised in the development and communication of this municipal strategy. The research was conducted with Hessequa Municipality, a local authority situated in the Western Cape Province of South Africa. A new aspect of the research was an attempt to consider renewable energy options as part of the municipal strategy, and not as a standalone project. Action research was undertaken and the resulting qualitative data were analysed using thematic analysis. Cognitive mapping was used to display the data and to analyse the causal relationships between different strategic themes. The causal relationships explicitly show that many opportunities for renewable energy solutions are evident in the form of: biomass-to-energy, low-carbon local economic development, small-scale embedded generation, waste-to-energy, and feed-in tariffs. The barriers for implementation are aging infrastructure and financial and legislative constraints. Participatory processes formed an integral part of the strategy formulation, and a unique visualised strategy was developed for communication with local citizens—a first for a local municipality in South Africa.

Cobalt Phosphides Nanocrystals Encapsulated by P-Doped Carbon and Married with P-Doped Graphene for Overall Water Splitting.

As one class of important functional materials, transition metal phosphides (TMPs) nanostructures show promising applications in catalysis and energy storage fields. Although great progress has been achieved, phase-controlled synthesis of cobalt phosphides nanocrystals or related nanohybrids remains a challenge, and their use in overall water splitting (OWS) is not systematically studied. Herein, three kinds of cobalt phosphides nanocrystals encapsulated by P-doped carbon (PC) and married with P-doped graphene (PG) nanohybrids, including CoP@PC/PG, CoP-Co2 P@PC/PG, and Co2 P@PC/PG, are obtained through controllable thermal conversion of presynthesized supramolecular gels that contain cobalt salt, phytic acid, and graphene oxides at proper temperature under Ar/H2 atmosphere. Among them, the mixed-phase CoP-Co2 P@PC/PG nanohybrids manifest high electrocatalytic activity toward both hydrogen and oxygen evolution in alkaline media. Remarkably, using them as bifunctional catalysts, the fabricated CoP-Co2 P@PC/PG||CoP-Co2 P@PC/PG electrolyzer only needs a cell voltage of 1.567 V for driving OWS to reach the current density at 10 mA cm-2 , superior to their pure-phase counterparts and recently reported bifunctional catalysts based devices. Also, such a CoP-Co2 P@PC/PG||CoP-Co2 P@PC/PG device exhibits outstanding stability for OWS. This work may shed some light on optimizing TMPs nanostructures based on phase engineering, and promote their applications in OWS or other renewable energy options.

Is Ghana Ready to Attain Sustainable Development Goal (SDG) Number 7?—A Comprehensive Assessment of Its Renewable Energy Potential and Pitfalls

Ghana has declared support for the UN Sustainable Development Goal (SDG) number seven which most importantly target ensuring universal access to affordable, reliable and modern energy services. This target presents a formidable challenge to Ghana because the country still relies mainly on traditional biomass as its primary source of energy coupled with a chronically fragile hydropower sector. In this study, we assess Ghana’s potential in achieving sustainable goal number seven. Specifically, we comprehensively review the breakthroughs and impediments Ghana has experienced in its efforts towards improving its renewable energy potential. We note that while Ghana has made significant stride toward attaining energy efficiency, its effort at large-scale biofuel development hit a snag due to issues of “land grabbing” emanating both from local and foreign entities. In another breadth, several pilot studies and research initiatives have demonstrated the possibility of diversifying the energy sector with other renewable energy options including solar, wind, and small hydro. In spite of challenges encountered with the development of biofuels, our review concludes that Ghana retains vast reserves of renewable energy potential, which can be harnessed with the constantly improving technological advancements as it pursues SDG number seven.

Power Stability Enhancement of SCIG and DFIG Based Wind Turbine Using Controlled-SMES

Several installed electrical power systems have a traditional type of wind power (WP) generators called squirrel cage induction generator (SCIG). However, SCIG is not the best type of WP in which it has a harmful impact on the stability of power systems. Therefore, with the increase in the loads especially at transient events, the SCIG will lead to system instability. Hence, it is necessary to increase the penetration level of WP by using more efficient generators, such as the doubly-fed induction generator (DFIG). At transient events such as increasing in the loads causes fluctuation of frequency and voltage of power systems. So, it is necessary to use controlled energy storage units to improve the stability of WP. The system used for studying consists of a grid connected to 25 kV bus through a step-down transformer and transmission line supplied initially by SCIG-based WP then supported by DFIG to increase penetration level and covers the increase in the loads. The superconducting magnetic energy storage (SMES) units are proficient in response, efficiency, and lifetime in contrast to other categories of energy storage systems, which make it a favored option for renewable energy. If SMES is combined with DFIG and SCIG, it increases the energy capacity of the total system. The SMES-controller is based on fuzzy logic control (FLC). The models of SMES, SCIG-based WP, and DFIG-based WP are demonstrated with MATLAB/SIMULINK, and the results illustrate the success of the proposed control to minimizing the voltage and frequency fluctuations during the transient events. Also, the model illustrates that the performance of DFIG on voltage and frequency stability is better than that of SCIG.

Quantitative priority estimation model for evaluation of various non-edible plant oils as potential biodiesel feedstock

Energy security, fluctuating petroleum prices, resource depletion issues and global climate change have driven countries to consider adding alternative and renewable energy options to their conventional energy share. The use of biofuel such as non-edible oils-based biodiesel is as an option over conventional diesel and could be important for the development of a sustainable and eco-friendly energy resource. The aim of the present study was to select the most feasible non-edible plant oil as biodiesel feedstock by using Analytic Hierarchy Process (AHP), one of the multi-criteria decision making methods based on priority estimation model. Among various non-edible plant oils which are widely available in the South-East-Asian region, selection of the most feasible plant oil was evaluated based on seven criteria; seed oil yield, oil yield, free fatty acid (FFA) content, cold filter plugging point, oxidation stability, easiness to grow in marginal land, and availability in tropical areas. The obtained results from priority determination showed that nyamplung was the most efficient feedstock of biodiesel for the industry with the criteria weightage of 0.180. It was followed by kemiri sunan (2 nd order) having weightage of 0.164, physic nut 0.150 (3 rd order), indian beech 0.107(4 th order), indian milkweed 0.095(5 th order), lead 0.092 (6 th order), kapok 0.076 (7 th order), cassia 0.049 (8 th order), soursop 0.043 (9 th order) and monkey pod 0.043 (10 th order). This study highlights an insight into multi-criteria decision making technique to assess the feasible plant oil for biodiesel production that could aid decision-making in the industry and policy development, particularly for the South-East-Asian region.

Pathways for Clean Bio Energy in Rural India: Present Challenges and Future Scenarios

The mission of achieving universal access to clean energy is still a crucial distant ambition particularly amongst the developing nations. However, progressive countries like India has a substantial concern in tumbling its reliance on fossil fuels and encouraging the use of renewable energy options to provide access to clean energy. India presents a favourable setting for accelerating the use and internalisation of bioenergy sources towards the path of clean energy for all. Almost 25% of India's energy arrives from bio resources, predominantly nearly 70% of rural inhabitants relied on biomass resources to congregate their everyday energy requirements. In particularly, biogas is one of the emerging bioenergy resources in rural India. This study analyses present challenges and future scenarios in the context of biogas by using futures methods. The policy findings of this study not only demonstrate crucial drivers but will also help the government to achieve its ambitious mission clean energy for all.

Feasibility analysis of renewable energy options for the union territory of Lakshadweep Islands

The power generation of most islands depends mainly on costly oil. Since the cost of energy is very high so these are the best test place for the implementation of the new technologies. We have considered the case of Lakshadweep Island which is one of a union territory of India. In Lakshadweep electricity is mainly generated from diesel generator sets. In this paper, an investigation has been made to find out total available potential of solar, wind and biomass in five islands of union territory of Lakshadweep. If we start generating up to the available potential then some islands will become renewable islands and this will increase the reliability, employment and decreases the cost of energy generation and pollution. Pearl and Logistic models have been used to find out the growth rate of SPV power generation. Using these models we find out that in how many years we will achieve the total available potential. After this, we have proposed a model of hybrid energy power generation for Kavaratti Island. The simulations and techno-economic evaluations have been done with the help of hybrid optimisation model for electric renewables software. Thousands of simulations have been carried out to achieve an optimal autonomous system configuration, in terms of system net present cost and cost of energy.

Comparison of Middle-Sized PTC and PV Power Plants for METU NCC

Since usage of fossil fuels for producing electricity causes climate change, renewable energy options have become one of the best substitution for fossil fuels. Solar energy promises high amount of resources for producing electricity. Among solar energy alternatives, Photovoltaic (PV) and Parabolic Trough Collectors (PTC) are dominant in the market. This paper compares middle size of PV and PTC power plant for the electricity need of Middle East Technical University Northern Cyprus Campus. Based on the maximum hourly demand of METU NCC, both PV and PTC are sized to 3 MWe. The simulations were performed via SAM software using the hourly values from typical meteorological data, which include solar irradiation, wind speed, dry and wet bulb temperatures, relative humidity and pressure. For the PTC and PV plants, commercially available components are used. The scenario assumes METU NCC to be a grid-connected micro-grid with one-way tariff, so that any deficit energy can be met by the utility and any excess energy produced by the suggested renewable energy systems will be given to the grid for free. The results indicate that 3 MW PV plant would generate annual energy of about 4.95 GWh with a capacity factor of 18.9%. These numbers would yield to a LCOE value of 2.60 ¢/kWh. On the other hand, the suggested 3 MW PTC plant with 2 solar multiple would supply about annual energy of 6.3 GWh at a capacity factor of 24.0%. The LCOE of the energy from PTC plant was estimated to be 8.47 ¢/kWh due to high capital and operation cost of PTC plants compared to PV plants. However, over years the cost of PTC power plants has been decreasing. Additionally, both PTC plant and PV plant would consume water only for cleaning purposes that makes them suitable for Cyprus water scarcity conditions. Overall, this study shows pros and cons of middle-sized PV and PTC plants with the case study of METU NCC.
 
 Keywords: economic comparison, levelized cost of energy, parabolic trough, photovoltaic, renewable energy, solar energy

Electric Power Crisis in Nigeria: A Strategic Call for Change of Focus to Renewable Sources

In all ramifications, the development and economic prosperity of a nation substantially depend on her power or energy sector. Reliable access to the electric power needed by several homes and businesses remains a great obstacle facing Nigeria. More than ever, the social-economic wellbeing of Nigeria is under severe threat due to formidable challenges in her Power sector. The manufacturing industries are folding up, while others are relocating their production plants to more friendly havens because of the high cost of doing business. This paper reviews various renewable energy options available to Nigeria and the National Renewable Energy and Energy Efficiency Policy (NREEEP). It also identified the major factors militating against renewable energy development in Nigeria, proffering possible way forward to assist renewable energy policy implementation.

Challenges in Environmental Sustainability of renewable energy options in Singapore

Renewable and sustainable are often used synonymously. This study examines the sustainability of switching from fossil-based electricity generation to renewable energy systems. Life cycle assessment (LCA) of both fossil- and renewable-based electricity generation were modeled for four environmental impact categories, in the context of Singapore city. The LCA method followed the CML methodology. Four major environmental impacts were calculated: global warming potential (GWP), acidification potential (AP), eutrophication potential (EP) and human toxicity potential (HTP). The cradle-to-gate analyses were done for various types of electricity supply sources: Solar photovoltaics (PV), biogas, municipal waste incineration, natural gas, coal and oil. The current mix of 95.2% natural gas, 3% incineration, 1% petroleum products and 0.8% coal was used as baseline for comparison with other mixes. The results showed that having a high proportion of electricity generated from solar PVs can produce ten times higher HTP than baseline scenario. Similarly, electricity from biogas can produce eight times higher AP and EP than baseline. Further analysis showed that HTP from solar PVs impacts locally, but mostly external to Singapore. AP from biogas impacts regionally, within and without Singapore. Policies about renewable energy in the overall electricity mix would thus be value- based, rather than purely economic or environmental.

Cost savings and emission reduction capability of wind-integrated power systems

In the face of energy crisis and environmental impacts of conventional energy sources, renewable energy sources have attracted tremendous interest. Among many resources, wind energy has proven to be a promising renewable energy option in recent times. The primary objective of utilizing renewable energy is its environmental sustainability and the idea of emission reduction constitutes a prominent part in it. The emission here refers to the CO2, SO2 and NOx emissions from thermal power plants. However, recent research works suggest that there remains a considerable anomaly between the claims of emission reduction by wind energy developers and the actual emissions, particularly with the integration of wind power into the grid system. The estimation methodology involving tools like wind resource assessment and energy capture may not provide accurate estimates due to some power system generation and operational constraints. The objective of the present study is to analyse the impact of wind turbine ratings and economic emission dispatch (EED) on the generation cost and emissions in wind integrated power systems. In this regard, the study investigates the concept of emission factor and wind-integrated EED. Wind turbines available at different rated power and rated speeds are incorporated in four different test power systems and the actual cost and emissions over a selected period are evaluated. Finally, the impact of the wind power integration on the generation cost savings and emission reduction is investigated.