Pub Date : 2022-06-17DOI: 10.17159/2413-3051/2022/v33i2a9200
N. Bhagwan, M. Evans
Fourth Industrial Revolution (4IR) technologies have elevated the capabilities and possibilities of improvement and efficiency in the energy sector. This paper interrogates how energy companies in South Africa, Germany and China apply 4IR technologies. A total of 26 energy companies in those countries were surveyed. An analysis was carried out using the Cronbach Alpha, Kruskal-Wallis and Mann-Whitney tests. Survey results indicate that 85% of companies acknowledge good levels of participation in the 4IR, and were clear about which 4IR technologies are important, although few companies develop these themselves. Technologies enabling access to big, real-time data (BRTD) and BRTD analysis software, are valued the most in measured importance, efficiency, reliability and ability to be integrated across the energy system. The transfer of data using the Internet of things ranked highly as a 4IR technology, whereas artificial intelligence, robotics and machine-human integration (also referred to as machine-human interaction) are considered less important, efficient, and reliable. China rates 4IR technologies as more important than South Africa and Germany do. For South Africa to be competitive in the global energy sector it needs to engage with and embrace 4IR technologies to a greater extent.
{"title":"A comparative analysis of the application of Fourth Industrial Revolution technologies in the energy sector: A case study of South Africa, Germany and China","authors":"N. Bhagwan, M. Evans","doi":"10.17159/2413-3051/2022/v33i2a9200","DOIUrl":"https://doi.org/10.17159/2413-3051/2022/v33i2a9200","url":null,"abstract":"Fourth Industrial Revolution (4IR) technologies have elevated the capabilities and possibilities of improvement and efficiency in the energy sector. This paper interrogates how energy companies in South Africa, Germany and China apply 4IR technologies. A total of 26 energy companies in those countries were surveyed. An analysis was carried out using the Cronbach Alpha, Kruskal-Wallis and Mann-Whitney tests. Survey results indicate that 85% of companies acknowledge good levels of participation in the 4IR, and were clear about which 4IR technologies are important, although few companies develop these themselves. Technologies enabling access to big, real-time data (BRTD) and BRTD analysis software, are valued the most in measured importance, efficiency, reliability and ability to be integrated across the energy system. The transfer of data using the Internet of things ranked highly as a 4IR technology, whereas artificial intelligence, robotics and machine-human integration (also referred to as machine-human interaction) are considered less important, efficient, and reliable. China rates 4IR technologies as more important than South Africa and Germany do. For South Africa to be competitive in the global energy sector it needs to engage with and embrace 4IR technologies to a greater extent.","PeriodicalId":15666,"journal":{"name":"Journal of Energy in Southern Africa","volume":"73 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85708790","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-06-17DOI: 10.17159/2413-3051/2022/v33i2a13453
S. Clark, C. McGregor, J. Van Niekerk
Along with the load-shedding problem that Eskom is having with the current generation system, the operator is forced to use its peaking plants at Ankerlig and Gourikwa in the Western Cape much more than planned. The two plants are set up for dual fuel operations, able to be fuelled with diesel as well as gas. As Eskom does not have access to natural gas, both plants have been fuelled with diesel. For the last three years, 2019 through 2021, Eskom has expended an average of over R4 billion per year on diesel fuel for its peaking plants, with the majority of this at Ankerlig and Gourikwa. For 2022, in their request for a rate increase, Eskom noted that their anticipated diesel fuel expenditures will increase to over R6.5 billion. This could be reduced by more than half if the plants were fuelled with natural gas. The problem Eskom faces is sourcing natural gas to fuel these plants. There has been consideration of liquefied natural gas importation into the Western Cape that could be utilised to fuel the Ankerlig plant. However, the high capital cost for this option has led to delay in the commencement of this project. There is another alternative that can be implemented in a short time-frame, using currently available gas, in the form of liquefied petroleum gas. With this fuel, the Ankerlig peaking plant could be switched to gas fuel and Eskom would have a significant reduction in the cost of fuel. In this study the economic benefit of this fuel change option is analysed.
{"title":"Using liquefied petroleum gas to reduce the operating cost of the Ankerlig peaking power plant in South Africa","authors":"S. Clark, C. McGregor, J. Van Niekerk","doi":"10.17159/2413-3051/2022/v33i2a13453","DOIUrl":"https://doi.org/10.17159/2413-3051/2022/v33i2a13453","url":null,"abstract":"Along with the load-shedding problem that Eskom is having with the current generation system, the operator is forced to use its peaking plants at Ankerlig and Gourikwa in the Western Cape much more than planned. The two plants are set up for dual fuel operations, able to be fuelled with diesel as well as gas. As Eskom does not have access to natural gas, both plants have been fuelled with diesel. For the last three years, 2019 through 2021, Eskom has expended an average of over R4 billion per year on diesel fuel for its peaking plants, with the majority of this at Ankerlig and Gourikwa. For 2022, in their request for a rate increase, Eskom noted that their anticipated diesel fuel expenditures will increase to over R6.5 billion. This could be reduced by more than half if the plants were fuelled with natural gas. The problem Eskom faces is sourcing natural gas to fuel these plants. There has been consideration of liquefied natural gas importation into the Western Cape that could be utilised to fuel the Ankerlig plant. However, the high capital cost for this option has led to delay in the commencement of this project. There is another alternative that can be implemented in a short time-frame, using currently available gas, in the form of liquefied petroleum gas. With this fuel, the Ankerlig peaking plant could be switched to gas fuel and Eskom would have a significant reduction in the cost of fuel. In this study the economic benefit of this fuel change option is analysed.","PeriodicalId":15666,"journal":{"name":"Journal of Energy in Southern Africa","volume":"27 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85440000","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-06-17DOI: 10.17159/2413-3051/2022/v33i2a9741
Lusani Faith Netshipise, K. Semenya
A large part of the world’s population still depends on firewood for domestic energy needs. If appropriately used, firewood can be considered a renewable energy resource. However, in many rural areas it is burnt in the open and in poorly ventilated kitchens, emitting smoke which is potentially harmful to those exposed to it. Interventions such as wood gasification stoves and electricity seem to have failed. This study evaluated factors influencing firewood consumption in households at the Thulamela local municipality. A household survey collected data from the selected community and it was analysed with Statistical Package for Social Scientists. The chi-square test was used to measure the degree of association between two categorical variables. The study showed a statistically significant association between the source of energy used and gender, education of the household head, employment status, income level, and energy expenditure. The chi-square test determined the association between the variables as the significance level is less than the p-value. The results also indicated that household energy consumption is influenced by level of income, gender, educational level of household head, employment status, number of members employed in a household, and energy expenditure. These factors are linked and mutually dependent. It is recommended that the use of renewable energy and modern energy technologies, such as liquefied petroleum gas, biogas and solar, should be encouraged, with the assistance of the municipality. There is also a need to raise environmental awareness. It is through education that people’s perception, attitudes and behaviour towards firewood consumption practices can be changed.
{"title":"Evaluating factors influencing firewood consumption in households at the Thulamela Local Municipality, South Africa","authors":"Lusani Faith Netshipise, K. Semenya","doi":"10.17159/2413-3051/2022/v33i2a9741","DOIUrl":"https://doi.org/10.17159/2413-3051/2022/v33i2a9741","url":null,"abstract":"A large part of the world’s population still depends on firewood for domestic energy needs. If appropriately used, firewood can be considered a renewable energy resource. However, in many rural areas it is burnt in the open and in poorly ventilated kitchens, emitting smoke which is potentially harmful to those exposed to it. Interventions such as wood gasification stoves and electricity seem to have failed. This study evaluated factors influencing firewood consumption in households at the Thulamela local municipality. A household survey collected data from the selected community and it was analysed with Statistical Package for Social Scientists. The chi-square test was used to measure the degree of association between two categorical variables. The study showed a statistically significant association between the source of energy used and gender, education of the household head, employment status, income level, and energy expenditure. The chi-square test determined the association between the variables as the significance level is less than the p-value. The results also indicated that household energy consumption is influenced by level of income, gender, educational level of household head, employment status, number of members employed in a household, and energy expenditure. These factors are linked and mutually dependent. It is recommended that the use of renewable energy and modern energy technologies, such as liquefied petroleum gas, biogas and solar, should be encouraged, with the assistance of the municipality. There is also a need to raise environmental awareness. It is through education that people’s perception, attitudes and behaviour towards firewood consumption practices can be changed.","PeriodicalId":15666,"journal":{"name":"Journal of Energy in Southern Africa","volume":"29 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84829365","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-03-17DOI: 10.17159/2413-3051/2022/v33i1a10381
N. M. Mutombo, B. Numbi
This work proposes an approach for the optimal sizing of a cylindrical heaving wave energy converter (WEC). The approach is based on maximising the absorbed power density (APD) of the buoy, with the diameter being the decision variable. Furthermore, two types of buoy shapes were compared to get the best option. The two buoy shapes are the cone cylinder buoy (CCB) and the hemisphere cylinder buoy (HCB). The aim was therefore to determine the best shape and as well as the optimal size of the cylindrical point absorber. To validate the approach, the simulation was performed under Durban (South Africa) sea characteristics of 3.6 m wave significant height and 8.5 s peak period, using the openWEC simulator. The buoy diameter range considered was from 0.5 m to 10 m for both shapes. Simulation results revealed that a diameter of 1 m was the optimal solution for both buoy shapes. Furthermore, the APD method revealed that the HCB was more efficient than the CCB. The power density of the HCB was 1070 W/m2, which was almost double the power density of the CCB, while the two shapes present almost the same absorbed power.
{"title":"Absorbed power density approach for optimal design of heaving point absorber wave energy converter: A case study of Durban sea characteristics","authors":"N. M. Mutombo, B. Numbi","doi":"10.17159/2413-3051/2022/v33i1a10381","DOIUrl":"https://doi.org/10.17159/2413-3051/2022/v33i1a10381","url":null,"abstract":"This work proposes an approach for the optimal sizing of a cylindrical heaving wave energy converter (WEC). The approach is based on maximising the absorbed power density (APD) of the buoy, with the diameter being the decision variable. Furthermore, two types of buoy shapes were compared to get the best option. The two buoy shapes are the cone cylinder buoy (CCB) and the hemisphere cylinder buoy (HCB). The aim was therefore to determine the best shape and as well as the optimal size of the cylindrical point absorber. To validate the approach, the simulation was performed under Durban (South Africa) sea characteristics of 3.6 m wave significant height and 8.5 s peak period, using the openWEC simulator. The buoy diameter range considered was from 0.5 m to 10 m for both shapes. Simulation results revealed that a diameter of 1 m was the optimal solution for both buoy shapes. Furthermore, the APD method revealed that the HCB was more efficient than the CCB. The power density of the HCB was 1070 W/m2, which was almost double the power density of the CCB, while the two shapes present almost the same absorbed power.","PeriodicalId":15666,"journal":{"name":"Journal of Energy in Southern Africa","volume":"11 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82602436","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-03-17DOI: 10.17159/2413-3051/2022/v33i1a7943
S. Tangwe, K. Kusakana
The study compared the coefficient of performance (COP) of two residential types of air source heat pump (ASHP) water heaters using statistical tests. The COPs were determined from the controlled volume of hot water (150, 50 and 100 L) drawn off from each tank at different time of use (morning, afternoon and evening) periods during summer and winter. Power meters, flow meters, and temperature sensors were installed on both types of ASHP water heater to measure the data needed to determine the COPs. The results showed that the mean COPs of the split and integrated type ASHP water heaters were 2.965 and 2.652 for summer and 2.657 and 2.202 for winter. In addition, the p-values of the groups COPs for the split and integrated type ASHP water heaters during winter and summer were 7.09 x 10-24 and 1.01 x 10-11, based on the one-way ANOVA and the Kruskal-Wallis tests. It can be concluded that, despite the year-round performance of both the split and integrated type ASHP water heaters, there is a significant difference in COP at 1% significance level among the four groups. Furthermore, both statistical tests confirmed these outcomes in the comparisons of the mean COPs among the four groups based on the multiple comparison algorithm.
{"title":"Using statistical tests to compare the coefficient of performance of air source heat pump water heaters","authors":"S. Tangwe, K. Kusakana","doi":"10.17159/2413-3051/2022/v33i1a7943","DOIUrl":"https://doi.org/10.17159/2413-3051/2022/v33i1a7943","url":null,"abstract":"The study compared the coefficient of performance (COP) of two residential types of air source heat pump (ASHP) water heaters using statistical tests. The COPs were determined from the controlled volume of hot water (150, 50 and 100 L) drawn off from each tank at different time of use (morning, afternoon and evening) periods during summer and winter. Power meters, flow meters, and temperature sensors were installed on both types of ASHP water heater to measure the data needed to determine the COPs. The results showed that the mean COPs of the split and integrated type ASHP water heaters were 2.965 and 2.652 for summer and 2.657 and 2.202 for winter. In addition, the p-values of the groups COPs for the split and integrated type ASHP water heaters during winter and summer were 7.09 x 10-24 and 1.01 x 10-11, based on the one-way ANOVA and the Kruskal-Wallis tests. It can be concluded that, despite the year-round performance of both the split and integrated type ASHP water heaters, there is a significant difference in COP at 1% significance level among the four groups. Furthermore, both statistical tests confirmed these outcomes in the comparisons of the mean COPs among the four groups based on the multiple comparison algorithm.\u0000 ","PeriodicalId":15666,"journal":{"name":"Journal of Energy in Southern Africa","volume":"5 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72691603","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-03-17DOI: 10.17159/2413-3051/2022/v33i1a9261
K. Amesho, E. Edoun, Sioni Iikela, Timoteus Kadhila, Lovisa R. Nangombe
The Namibian energy sector and other energy sectors across the globe are currently in a rapid transformation era that must respond to climate change, which directly affects energy infrastructure’s resilience to the effects of resource scarcities or extreme weather conditions. The energy sector must implement adaptation to guarantee the resilience of vital infrastructure to fulfil its regulatory commitments, which cover the elements of resilience and safety. Through investigating climate change adaptation and mitigation implementation in Namibia, this study validates the existence of these co-benefits where integration is fully observed. It employed a meta-analysis and content analysis to link the observed variables to the most recognised co-benefits. The findings suggest that integration is an efficient way to generate co-benefits that contribute positively to the climate change project. Effective leadership support is one way of realising such integration, either via public-private partnership or energy policy. Namibian energy policy, it is suggested, through voluntary tools and incentives, should create key public-private partnerships and promote management. These recommendations have application beyond the Namibian energy sector, and the lessons learned here could be implemented in scenarios outside of it.
{"title":"An empirical analysis of the co-benefits of integrating climate change adaptation and mitigation in the Namibian energy sector","authors":"K. Amesho, E. Edoun, Sioni Iikela, Timoteus Kadhila, Lovisa R. Nangombe","doi":"10.17159/2413-3051/2022/v33i1a9261","DOIUrl":"https://doi.org/10.17159/2413-3051/2022/v33i1a9261","url":null,"abstract":"The Namibian energy sector and other energy sectors across the globe are currently in a rapid transformation era that must respond to climate change, which directly affects energy infrastructure’s resilience to the effects of resource scarcities or extreme weather conditions. The energy sector must implement adaptation to guarantee the resilience of vital infrastructure to fulfil its regulatory commitments, which cover the elements of resilience and safety. Through investigating climate change adaptation and mitigation implementation in Namibia, this study validates the existence of these co-benefits where integration is fully observed. It employed a meta-analysis and content analysis to link the observed variables to the most recognised co-benefits. The findings suggest that integration is an efficient way to generate co-benefits that contribute positively to the climate change project. Effective leadership support is one way of realising such integration, either via public-private partnership or energy policy. Namibian energy policy, it is suggested, through voluntary tools and incentives, should create key public-private partnerships and promote management. These recommendations have application beyond the Namibian energy sector, and the lessons learned here could be implemented in scenarios outside of it.","PeriodicalId":15666,"journal":{"name":"Journal of Energy in Southern Africa","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90014471","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-03-17DOI: 10.17159/2413-3051/2022/v33i1a9344
M. Zietsman, T. Adefarati, R. C. Bansal, R. Naidoo
The capacity of power generation note needs to be increased globally, owing to population growth and industrial revolution. The conventional power plant across the world is inadequate to satisfy growing power demand. By optimally sizing and designing the clusters of renewable energy sources such as wind, microgrid operators can economically and environmentally sustainably provide a clean power solution that can increase the supply of electricity. Wind power (WP) generation can be utilised to reduce the stress on the power plants by minimising the peak demands in constrained distribution networks. Benefits of WP include increased energy revenue, increased system reliability, investment deferment, power loss reduction, and environmental pollution reduction. These will strengthen the performance of the power system and bring economic value to society. Moreover, many challenges are considered when integrating WP into the distribution system. These include protection device miscoordination, fundamental changes in the network topology, transmission congestion, bidirectional power flow, and harmonic current injections. In this paper, the economic cost and benefit analysis of optimal integration of WP into the distribution networks is investigated through a multi-objective analytical method. The aim is to see whether investment in the WP project is economically profitable and technically viable in the distribution system. The results obtained from the study can be utilised by power system operators, planners and designers as criteria to use WP for stimulating economic development and industrial revolution and can allow independent power producers to make appropriate investment decisions.
{"title":"Cost-benefit analysis of wind power integra-tion in distribution networks","authors":"M. Zietsman, T. Adefarati, R. C. Bansal, R. Naidoo","doi":"10.17159/2413-3051/2022/v33i1a9344","DOIUrl":"https://doi.org/10.17159/2413-3051/2022/v33i1a9344","url":null,"abstract":"The capacity of power generation note needs to be increased globally, owing to population growth and industrial revolution. The conventional power plant across the world is inadequate to satisfy growing power demand. By optimally sizing and designing the clusters of renewable energy sources such as wind, microgrid operators can economically and environmentally sustainably provide a clean power solution that can increase the supply of electricity. Wind power (WP) generation can be utilised to reduce the stress on the power plants by minimising the peak demands in constrained distribution networks. Benefits of WP include increased energy revenue, increased system reliability, investment deferment, power loss reduction, and environmental pollution reduction. These will strengthen the performance of the power system and bring economic value to society. Moreover, many challenges are considered when integrating WP into the distribution system. These include protection device miscoordination, fundamental changes in the network topology, transmission congestion, bidirectional power flow, and harmonic current injections. In this paper, the economic cost and benefit analysis of optimal integration of WP into the distribution networks is investigated through a multi-objective analytical method. The aim is to see whether investment in the WP project is economically profitable and technically viable in the distribution system. The results obtained from the study can be utilised by power system operators, planners and designers as criteria to use WP for stimulating economic development and industrial revolution and can allow independent power producers to make appropriate investment decisions.","PeriodicalId":15666,"journal":{"name":"Journal of Energy in Southern Africa","volume":"41 1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90475327","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-03-17DOI: 10.17159/2413-3051/2022/v33i1a5434
Deepti Charitar, A. Madhlopa
Desalination is increasingly becoming a crucial method for providing fresh water globally. However, most of the desalination technologies are energy-intensive and driven by fossil fuels that are contributing to climate change and other environmental problems. In this vein, renewable energy and energy efficiency are promising pillars of sustainable energy production and consumption, and the recovery of waste heat helps to augment the energy efficiency of a system. Based on the temperature (T) of the heat source, waste heat can be classified into three categories: low temperature (T<100°C), medium temperature (100°C£T<300°C) and high temp-erature (T³300°C). There is scarcity of review work on the integration of waste heat in desalination technologies. In this study, the progress in the utilisation of waste heat to drive thermal desalination processes has been investigated. It is found that 63% of waste heat streams are of low grade, which is still satisfactory for thermal desalination technologies that run on low-temperature heat sources. As of 2018, there was only one known thermal desalination plant driven by waste heat. Lack of data on waste heat, especially in developing countries, has been identified as a major challenge to the advancement of desalination technologies driven by this source of thermal energy. Other constraints are presented and discussed in this paper.
{"title":"Integration of waste heat in thermal desalination technologies: A review","authors":"Deepti Charitar, A. Madhlopa","doi":"10.17159/2413-3051/2022/v33i1a5434","DOIUrl":"https://doi.org/10.17159/2413-3051/2022/v33i1a5434","url":null,"abstract":"Desalination is increasingly becoming a crucial method for providing fresh water globally. However, most of the desalination technologies are energy-intensive and driven by fossil fuels that are contributing to climate change and other environmental problems. In this vein, renewable energy and energy efficiency are promising pillars of sustainable energy production and consumption, and the recovery of waste heat helps to augment the energy efficiency of a system. Based on the temperature (T) of the heat source, waste heat can be classified into three categories: low temperature (T<100°C), medium temperature (100°C£T<300°C) and high temp-erature (T³300°C). There is scarcity of review work on the integration of waste heat in desalination technologies. In this study, the progress in the utilisation of waste heat to drive thermal desalination processes has been investigated. It is found that 63% of waste heat streams are of low grade, which is still satisfactory for thermal desalination technologies that run on low-temperature heat sources. As of 2018, there was only one known thermal desalination plant driven by waste heat. Lack of data on waste heat, especially in developing countries, has been identified as a major challenge to the advancement of desalination technologies driven by this source of thermal energy. Other constraints are presented and discussed in this paper.","PeriodicalId":15666,"journal":{"name":"Journal of Energy in Southern Africa","volume":"20 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73918690","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-03-17DOI: 10.17159/2413-3051/2022/v33i1a8860
L.P. Bonokwane, O. O. Ololade
Being energy-autonomous has been suggested as a means of having sustainable energy in South Africa, where about 98% of electricity is derived from coal. Research has shown that biogas produced from animal wastes using a biodigester can be used as a source of renewable energy with the added benefits of a by-product called digestate, which can replace inorganic fertiliser. This study analyses the factors that influence smallholder farmers’ willingness to adopt a biodigester technology. It uses a structured questionnaire to acquire data from 80 respondents in Ngaka Modiri Molema District in North West Province, South Africa. The respondents were 30 livestock farmers and 29 farmers practising mixed farming. Five extension officers were also interviewed to establish their level of knowledge about the technology. Descriptive statistics and Fisher’s exact test were used to analyse the data. Factors such as gender, years of experience and family size were significant to willingness to adopt a biodigester. Farmers who were male and those with more years of experience were open to the idea, while those with larger families were less open to it, due to financial constraint. Overall, respondents practising mixed farming were more willing to adopt a biodigester than livestock farmers.
{"title":"Socio-economic factors affecting smallholder farmers’ willingness to adopt biodigester technology in South Africa","authors":"L.P. Bonokwane, O. O. Ololade","doi":"10.17159/2413-3051/2022/v33i1a8860","DOIUrl":"https://doi.org/10.17159/2413-3051/2022/v33i1a8860","url":null,"abstract":"Being energy-autonomous has been suggested as a means of having sustainable energy in South Africa, where about 98% of electricity is derived from coal. Research has shown that biogas produced from animal wastes using a biodigester can be used as a source of renewable energy with the added benefits of a by-product called digestate, which can replace inorganic fertiliser. This study analyses the factors that influence smallholder farmers’ willingness to adopt a biodigester technology. It uses a structured questionnaire to acquire data from 80 respondents in Ngaka Modiri Molema District in North West Province, South Africa. The respondents were 30 livestock farmers and 29 farmers practising mixed farming. Five extension officers were also interviewed to establish their level of knowledge about the technology. Descriptive statistics and Fisher’s exact test were used to analyse the data. Factors such as gender, years of experience and family size were significant to willingness to adopt a biodigester. Farmers who were male and those with more years of experience were open to the idea, while those with larger families were less open to it, due to financial constraint. Overall, respondents practising mixed farming were more willing to adopt a biodigester than livestock farmers.","PeriodicalId":15666,"journal":{"name":"Journal of Energy in Southern Africa","volume":"29 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89632003","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-03-17DOI: 10.17159/2413-3051/2022/v33i1a8611
I. M. Kwembur, J.L. Crozier McCleland, E. Van Dyk, F. Vorster
Potential induced degradation (PID) is a defect that has a severe effect on the performance of photovoltaic (PV) modules in field conditions. It is caused by leakage currents and the accumulation of sodium ions (Na+) between the anti-reflective coating and the encapsulation. In the experiment reported on here, PID was artificially induced through a PID stress test, where the surface of a poly-crystalline p‑type module was covered with an aluminium sheet connected to the positive terminal of a high voltage power supply (1000 V), while the short-circuited module terminals was biased to the negative terminal. This stress test was applied to two similar poly-crystalline p‑type modules, A and B, for 48 hours and 20 hours respectively. The duration of the stress test determines the degree of PID severity induced. The length of the test resulted in Module A’s power decreasing by 88% and Module B’s by 40%. Electroluminescence and current-voltage measurements were taken at regular intervals over a period of more than a year to monitor the natural recovery of the modules. These measurements show that the natural recovery of severe PID modules is possible, but slow. After the test period, the maximum power of Module A and Module B had recovered to 63% and 96% of the original level. PID experienced in the field is generally less severe than for the modules in this study, so PID recovery could be achieved by adopting a process of setting affected strings at open-circuit in turns.
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