Pub Date : 2019-05-16DOI: 10.17159/2413-3051/2019/V30I2A6076
T. Govindasamy, N. Chetty
South Africa continues to lag globally in the adoption of renewable energy systems despite a notable decrease in the cost of applicable renewable energy technologies over the past five years. Most applications of potential solar renewable energy systems are currently in various stages of investigation, leaving this readily accessible resource capacity idle. The present study proposes linear and non-linear analysis of multivariate models for estimating global solar radiation (GSR) received across five cities in South Africa. The significance of this study is to provide effective GSR estimation in the application of solar technologies, while increasing their implementation. The dependency of GSR on meteorological variables such as air temperature, relative humidity and relative sunshine duration was evaluated for January 2007 to June 2018 to realise estimation models for each of the study sites. The Hargreaves-Samani and Angstrom-Prescott empirical models served as the basis for single variable analysis of GSR reliance on each meteorological parameter and their relative variations. The results indicated that the proposed non-linear, multivariate equations perform better than the empirical models as well as linear, single variable regression equations. The suggested models are site-specific and demonstrate a strong correlation to historic GSR values with low, acceptable error indicators. It was also recognised that second- and third-order relationships between the clearness index and multiple meteorological variables provide a more accurate description of GSR for most of the cities under study. These methods are cost-effective, easily accessible and appropriate for the evaluation of the feasibility of solar photovoltaic technologies in South Africa.
{"title":"Non-linear multivariate models for estimating global solar radiation received across five cities in South Africa","authors":"T. Govindasamy, N. Chetty","doi":"10.17159/2413-3051/2019/V30I2A6076","DOIUrl":"https://doi.org/10.17159/2413-3051/2019/V30I2A6076","url":null,"abstract":"South Africa continues to lag globally in the adoption of renewable energy systems despite a notable decrease in the cost of applicable renewable energy technologies over the past five years. Most applications of potential solar renewable energy systems are currently in various stages of investigation, leaving this readily accessible resource capacity idle. The present study proposes linear and non-linear analysis of multivariate models for estimating global solar radiation (GSR) received across five cities in South Africa. The significance of this study is to provide effective GSR estimation in the application of solar technologies, while increasing their implementation. The dependency of GSR on meteorological variables such as air temperature, relative humidity and relative sunshine duration was evaluated for January 2007 to June 2018 to realise estimation models for each of the study sites. The Hargreaves-Samani and Angstrom-Prescott empirical models served as the basis for single variable analysis of GSR reliance on each meteorological parameter and their relative variations. The results indicated that the proposed non-linear, multivariate equations perform better than the empirical models as well as linear, single variable regression equations. The suggested models are site-specific and demonstrate a strong correlation to historic GSR values with low, acceptable error indicators. It was also recognised that second- and third-order relationships between the clearness index and multiple meteorological variables provide a more accurate description of GSR for most of the cities under study. These methods are cost-effective, easily accessible and appropriate for the evaluation of the feasibility of solar photovoltaic technologies in South Africa.","PeriodicalId":15666,"journal":{"name":"Journal of Energy in Southern Africa","volume":"33 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85338592","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 : 2019-03-25DOI: 10.17159/2413-3051/2019/V30I1A5430
C. Clohessy, G. Sharp, J. Hugo, E. Van Dyk
The drive to reduce fossil fuel dependency led to a surge in interest in renewable energy as a replacement fuel source, which provided research opportunities for vastly different domains. Statistical modelling was used extensively to assist in research. This study applied two statistical techniques that can be used in conjunction or independently to existing methods to validate solar resource data simulated from models. The case study, using a database from a Southern African Universities Radiometric Network, provided illustrative benefits to the methods proposed, while comparing them with some of the validation methods currently used. It was demonstrated that profile analysis plots are easy to interpret, as deviations between modelled and measured data over time are clearly observed, while traditional validation scatter plots are unable to distinguish these deviations.
{"title":"Inferential based statistical indicators for the assessment of solar resource data","authors":"C. Clohessy, G. Sharp, J. Hugo, E. Van Dyk","doi":"10.17159/2413-3051/2019/V30I1A5430","DOIUrl":"https://doi.org/10.17159/2413-3051/2019/V30I1A5430","url":null,"abstract":"The drive to reduce fossil fuel dependency led to a surge in interest in renewable energy as a replacement fuel source, which provided research opportunities for vastly different domains. Statistical modelling was used extensively to assist in research. This study applied two statistical techniques that can be used in conjunction or independently to existing methods to validate solar resource data simulated from models. The case study, using a database from a Southern African Universities Radiometric Network, provided illustrative benefits to the methods proposed, while comparing them with some of the validation methods currently used. It was demonstrated that profile analysis plots are easy to interpret, as deviations between modelled and measured data over time are clearly observed, while traditional validation scatter plots are unable to distinguish these deviations. \u0000 ","PeriodicalId":15666,"journal":{"name":"Journal of Energy in Southern Africa","volume":"69 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85251916","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 : 2019-03-25DOI: 10.17159/2413-3051/2019/V30I1A2473
F. Roos, R. Bansal
This study reports on a case study in Grootegeluk Mine: Exxaro Coal, Lephalale, South Africa, in terms of power factor correction (PFC), load flow, harmonic frequency scans and harmonic voltage distortion analyses. The DIgSilent PowerFactory software was used for network simulations. Harmonic and reactive power compensation techniques were compared in terms of filter type evolution and technology advancement, with the use of simple trade-off criteria such as cost-effectiveness versus performance. It was found that both passive and hybrid filters were more favourable and could effectively compensate all voltage and current harmonics and reactive power for large nonlinear loads. The installation of switched PFC filter banks tuned at the fifth harmonic order accommodates future network growth and this solution can be rolled out to any mining industry as a benchmark to lower energy cost and maximise savings achievable on the electricity bill.
{"title":"Reactive power and harmonic compensation: A case study for the coal-mining industry","authors":"F. Roos, R. Bansal","doi":"10.17159/2413-3051/2019/V30I1A2473","DOIUrl":"https://doi.org/10.17159/2413-3051/2019/V30I1A2473","url":null,"abstract":"This study reports on a case study in Grootegeluk Mine: Exxaro Coal, Lephalale, South Africa, in terms of power factor correction (PFC), load flow, harmonic frequency scans and harmonic voltage distortion analyses. The DIgSilent PowerFactory software was used for network simulations. Harmonic and reactive power compensation techniques were compared in terms of filter type evolution and technology advancement, with the use of simple trade-off criteria such as cost-effectiveness versus performance. It was found that both passive and hybrid filters were more favourable and could effectively compensate all voltage and current harmonics and reactive power for large nonlinear loads. The installation of switched PFC filter banks tuned at the fifth harmonic order accommodates future network growth and this solution can be rolled out to any mining industry as a benchmark to lower energy cost and maximise savings achievable on the electricity bill. \u0000 ","PeriodicalId":15666,"journal":{"name":"Journal of Energy in Southern Africa","volume":"86 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73976303","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 : 2019-03-22DOI: 10.17159/2413-3051/2019/V30I1A5226
Monga F. Twite, L. Snyman, J. De Koker, A. Yusuff
A low-cost heat-exchanger system that can be used in high-pressure/low-pressure isolated solar water-heating systems in South Africa was developed for household applications. The combination of a copper coil and electrical heater allowed for isolation of the high-pressure and low-pressure sections of the system and enabled the utilisation of large low-cost solar heat-absorber platforms that operated at low pressure with a low risk of fouling and leaking. The design comprised a copper coil heat exchanger to be installed inside a conventional geyser, to replace the normal heating element and thermostat system in a conventional commercially available household geyser. The electric heating element still supplements the system in low solar energy conditions. The circulation in the system is created by a small separate photovoltaic panel and a circulation pump. An integrated switch allows the system to alternate between conventional electrical heating and solar water-heating according to prevailing weather conditions. Current tests show that the system of 15 m2 area can be installed at a cost of approximately ZAR 10 000–12 000. The system can provide hot water at approximately 12 cents per kWh, with a total heat storage capacity of up to 10 kWh per day. This implies a saving to the customer of up to ZAR 600 per month. The accumulated saving to a household over the ten-year lifetime of the product is estimated at ZAR 200 000. As the thermal energy storage capacity of current systems as available on the local market is approximately 1 kWhr per day for a 2 m2 collector. A typical increase in thermal energy collection capacity of tenfold more than the capability of conventional systems on the market is hence achieved. The system offers implementation possibilities for South Africa’s low-cost housing schemes and can provide for creating numerous new business and job opportunities on the African continent with its abundant solar irradiation resources.
{"title":"Development of a large-area, low-cost solar water-heating system for South Africa with a high thermal energy collection capacity","authors":"Monga F. Twite, L. Snyman, J. De Koker, A. Yusuff","doi":"10.17159/2413-3051/2019/V30I1A5226","DOIUrl":"https://doi.org/10.17159/2413-3051/2019/V30I1A5226","url":null,"abstract":"A low-cost heat-exchanger system that can be used in high-pressure/low-pressure isolated solar water-heating systems in South Africa was developed for household applications. The combination of a copper coil and electrical heater allowed for isolation of the high-pressure and low-pressure sections of the system and enabled the utilisation of large low-cost solar heat-absorber platforms that operated at low pressure with a low risk of fouling and leaking. The design comprised a copper coil heat exchanger to be installed inside a conventional geyser, to replace the normal heating element and thermostat system in a conventional commercially available household geyser. The electric heating element still supplements the system in low solar energy conditions. The circulation in the system is created by a small separate photovoltaic panel and a circulation pump. An integrated switch allows the system to alternate between conventional electrical heating and solar water-heating according to prevailing weather conditions. Current tests show that the system of 15 m2 area can be installed at a cost of approximately ZAR 10 000–12 000. The system can provide hot water at approximately 12 cents per kWh, with a total heat storage capacity of up to 10 kWh per day. This implies a saving to the customer of up to ZAR 600 per month. The accumulated saving to a household over the ten-year lifetime of the product is estimated at ZAR 200 000. As the thermal energy storage capacity of current systems as available on the local market is approximately 1 kWhr per day for a 2 m2 collector. A typical increase in thermal energy collection capacity of tenfold more than the capability of conventional systems on the market is hence achieved. The system offers implementation possibilities for South Africa’s low-cost housing schemes and can provide for creating numerous new business and job opportunities on the African continent with its abundant solar irradiation resources.","PeriodicalId":15666,"journal":{"name":"Journal of Energy in Southern Africa","volume":"28 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74068594","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 : 2019-03-08DOI: 10.17159/2413-3051/2019/V30I1A5267
Karidewa Nyeinga, D. Okello, O. Nydal
This study describes a 3D ray tracer model for analysis of a small-scale solar concentrating system where thermal heat is collected for cooking purposes. Emitted sun rays were traced from the source through all reflections until they intercepted with the receiver or were lost. The algorithm of the ray tracer and its implementation in MATLAB is clearly described. The ray tracer was programmed to contribute to the development of small-scale concentrating solar energy systems with integrated heat storage units. The ray tracer was demonstrated for selected cases where continuous reflecting surfaces and flat mirror-tiled surfaces were compared. Off-focus sensitivity analysis was shown and this could provide guidelines for the required solar tracking accuracy. The flux distribution on the absorber was analysed and found to be concentrated on a small area on the target for continuous reflecting surfaces and having high intensities. However, for reflectors with mirror tiles, an elongated image was formed centred on the focal point with low intensities. Small misalignment of the reflector in the order 0.2° had minimal impact on the interception ratio, but any further increase in the tracking errors caused a sudden drop in the interception ratio to zero. Results showed that there is close agreement in flux distribution and the tracking error impact on interception ratio, when compared with the literature. This model could be a useful tool when designing the reflection and absorption components of solar concentrators for complex systems with several components in a non-symmetric 3D arrangement.
{"title":"A ray tracer model for analysis of solar concentrating systems","authors":"Karidewa Nyeinga, D. Okello, O. Nydal","doi":"10.17159/2413-3051/2019/V30I1A5267","DOIUrl":"https://doi.org/10.17159/2413-3051/2019/V30I1A5267","url":null,"abstract":"This study describes a 3D ray tracer model for analysis of a small-scale solar concentrating system where thermal heat is collected for cooking purposes. Emitted sun rays were traced from the source through all reflections until they intercepted with the receiver or were lost. The algorithm of the ray tracer and its implementation in MATLAB is clearly described. The ray tracer was programmed to contribute to the development of small-scale concentrating solar energy systems with integrated heat storage units. The ray tracer was demonstrated for selected cases where continuous reflecting surfaces and flat mirror-tiled surfaces were compared. Off-focus sensitivity analysis was shown and this could provide guidelines for the required solar tracking accuracy. The flux distribution on the absorber was analysed and found to be concentrated on a small area on the target for continuous reflecting surfaces and having high intensities. However, for reflectors with mirror tiles, an elongated image was formed centred on the focal point with low intensities. Small misalignment of the reflector in the order 0.2° had minimal impact on the interception ratio, but any further increase in the tracking errors caused a sudden drop in the interception ratio to zero. Results showed that there is close agreement in flux distribution and the tracking error impact on interception ratio, when compared with the literature. This model could be a useful tool when designing the reflection and absorption components of solar concentrators for complex systems with several components in a non-symmetric 3D arrangement.","PeriodicalId":15666,"journal":{"name":"Journal of Energy in Southern Africa","volume":"26 1","pages":"8-20"},"PeriodicalIF":0.0,"publicationDate":"2019-03-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78950654","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 : 2019-03-08DOI: 10.17159/2413-3051/2019/V30I1A5452
H. Baloyi, Gary M. Dugmore
For this study, waste coal fines were treated with live microalgae slurry at varying biomass ratios to form coal-microalgae blends. The parent samples and the coal-microalgae blends were analysed for their proximate, ultimate and calorific values. Thermogravimetric experiments were performed on the parent samples and coal-microalgae blends under inert conditions. The aim was to investigate the effects of loading live microalgae slurry onto the waste coals with respect to the overall chemical and thermal characteristics of the coal. Based on the analysed results, the blending of microalgae slurry with coal has been shown to enhance thermal decomposition of coal. Coal-microalgae blends have a higher hydrogen content and volatile matter content than coal. Moreover, the presence of microalgae results in faster rates of decomposition at lower temperatures (200–400 ºC), and lower residual mass fraction. The blending of microalgae slurries with waste coal appears to be suitable for enhancing the thermal reactivity of waste coal as well as improving the thermal conversion of waste coal.
{"title":"Influences of microalgae biomass on the thermal behaviour of waste coal fines","authors":"H. Baloyi, Gary M. Dugmore","doi":"10.17159/2413-3051/2019/V30I1A5452","DOIUrl":"https://doi.org/10.17159/2413-3051/2019/V30I1A5452","url":null,"abstract":"For this study, waste coal fines were treated with live microalgae slurry at varying biomass ratios to form coal-microalgae blends. The parent samples and the coal-microalgae blends were analysed for their proximate, ultimate and calorific values. Thermogravimetric experiments were performed on the parent samples and coal-microalgae blends under inert conditions. The aim was to investigate the effects of loading live microalgae slurry onto the waste coals with respect to the overall chemical and thermal characteristics of the coal. Based on the analysed results, the blending of microalgae slurry with coal has been shown to enhance thermal decomposition of coal. Coal-microalgae blends have a higher hydrogen content and volatile matter content than coal. Moreover, the presence of microalgae results in faster rates of decomposition at lower temperatures (200–400 ºC), and lower residual mass fraction. The blending of microalgae slurries with waste coal appears to be suitable for enhancing the thermal reactivity of waste coal as well as improving the thermal conversion of waste coal.","PeriodicalId":15666,"journal":{"name":"Journal of Energy in Southern Africa","volume":"61 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-03-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90091450","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 : 2018-12-07DOI: 10.17159/2413-3051/2018/V29I4A4748
M. Majodina, J. Botai, H. Rautenbach
Meteorological factors have an influence on global energy systems. This study reviewed some of the latest research contributions from other global studies on climate change impacts, energy transportation and international collaboration in the energy-meteorology sector. It is a summary of relevant South African research on energy demand, forecasting and vulnerability to meteorological conditions. International weather-energy partnerships are growing fast, while the Global Framework for Climate Services has provided a global framework for scientific collaboration across sectors to assist with climate-related risk management and decision-making. The uptake in developing regions has remained slow, however, particularly in Africa, where basic requirements such as meteorological observations are still sought. This review found that studies on the impact that future projections of climate change and variability might have on the South African electricity transmission network were inadequate. A deeper understanding of such impacts on the electricity infrastructure would assist considerably with risk management and decision-making; consequently contributing to the sustainable provision of electricity in South Africa.
{"title":"The vulnerability of the South African electricity transmission network infrastructure to weather and climate: A review","authors":"M. Majodina, J. Botai, H. Rautenbach","doi":"10.17159/2413-3051/2018/V29I4A4748","DOIUrl":"https://doi.org/10.17159/2413-3051/2018/V29I4A4748","url":null,"abstract":"Meteorological factors have an influence on global energy systems. This study reviewed some of the latest research contributions from other global studies on climate change impacts, energy transportation and international collaboration in the energy-meteorology sector. It is a summary of relevant South African research on energy demand, forecasting and vulnerability to meteorological conditions. International weather-energy partnerships are growing fast, while the Global Framework for Climate Services has provided a global framework for scientific collaboration across sectors to assist with climate-related risk management and decision-making. The uptake in developing regions has remained slow, however, particularly in Africa, where basic requirements such as meteorological observations are still sought. This review found that studies on the impact that future projections of climate change and variability might have on the South African electricity transmission network were inadequate. A deeper understanding of such impacts on the electricity infrastructure would assist considerably with risk management and decision-making; consequently contributing to the sustainable provision of electricity in South Africa.","PeriodicalId":15666,"journal":{"name":"Journal of Energy in Southern Africa","volume":"12 1","pages":"51-59"},"PeriodicalIF":0.0,"publicationDate":"2018-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76446979","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 : 2018-12-07DOI: 10.17159/2413-3051/2018/V29I4A5581
Jarrad Wright, J. Coller
The requirement for increased investment in electrical energy infrastructure in the Southern African Power Pool (SAPP) region is contextualised. Background on the SAPP is provided for reference. A brief assessment of historical capacity adequacy in the SAPP region shows historically sustained levels of inadequacy as well as distinctive investment cycles primarily as a result of administratively determined generation capacity investments within each member country. The introduction of an appropriately designed capacity mechanism is proposed for SAPP to facilitate system adequacy and incentivise long-term capacity investment.
{"title":"System adequacy in the Southern African Power Pool: A case for capacity mechanisms","authors":"Jarrad Wright, J. Coller","doi":"10.17159/2413-3051/2018/V29I4A5581","DOIUrl":"https://doi.org/10.17159/2413-3051/2018/V29I4A5581","url":null,"abstract":"The requirement for increased investment in electrical energy infrastructure in the Southern African Power Pool (SAPP) region is contextualised. Background on the SAPP is provided for reference. A brief assessment of historical capacity adequacy in the SAPP region shows historically sustained levels of inadequacy as well as distinctive investment cycles primarily as a result of administratively determined generation capacity investments within each member country. The introduction of an appropriately designed capacity mechanism is proposed for SAPP to facilitate system adequacy and incentivise long-term capacity investment.","PeriodicalId":15666,"journal":{"name":"Journal of Energy in Southern Africa","volume":"34 1","pages":"37-50"},"PeriodicalIF":0.0,"publicationDate":"2018-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77345579","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 : 2018-12-03DOI: 10.17159/2413-3051/2018/V29I4A3417
M. D. Wit, M. Heun, D. Crookes
Integrated energy-economic modeling is needed to support the development of energy and carbon policies. We propose that a systems dynamic modeling approach is needed; one that includes (a) dynamics (b) endogenous treatment of uncertainty and risks, and (c) both aggregate economic and disaggregate technical or engineering levels of analysis. To support the future development of integrated energy-economic models we review and organise the literature on energy-economy interactions into subsections covering (a) the key factors or components, (b) the relationships among these components, (c) a quantification of parameters and (d) implications for the development of an integrated energy-economic systems dynamic model. The literature is organized in discussions on economic growth and the factors of production, elasticities, macro- and technical substitutability, energy cost shares, heat engine efficiencies and energy services efficiencies. We observe non-linear relationships in production and consumption, large variations among price and income elasticity values across time frames, across countries and regions, and across energy goods, far from perfect substitution among factors of production and among energy goods on a macro level, technical/engineering limits to substitution on a micro level, as well as engineering and behavioural limits on what can be achieved with increased efficiencies. We therefore support the call to develop integrated energy-economic systems dynamic models that are able to provide new insight into the nature of energy-economic transitions
{"title":"An overview of salient factors, relationships and values to support integrated energy-economic systems dynamic modelling","authors":"M. D. Wit, M. Heun, D. Crookes","doi":"10.17159/2413-3051/2018/V29I4A3417","DOIUrl":"https://doi.org/10.17159/2413-3051/2018/V29I4A3417","url":null,"abstract":"Integrated energy-economic modeling is needed to support the development of energy and carbon policies. We propose that a systems dynamic modeling approach is needed; one that includes (a) dynamics (b) endogenous treatment of uncertainty and risks, and (c) both aggregate economic and disaggregate technical or engineering levels of analysis. To support the future development of integrated energy-economic models we review and organise the literature on energy-economy interactions into subsections covering (a) the key factors or components, (b) the relationships among these components, (c) a quantification of parameters and (d) implications for the development of an integrated energy-economic systems dynamic model. The literature is organized in discussions on economic growth and the factors of production, elasticities, macro- and technical substitutability, energy cost shares, heat engine efficiencies and energy services efficiencies. We observe non-linear relationships in production and consumption, large variations among price and income elasticity values across time frames, across countries and regions, and across energy goods, far from perfect substitution among factors of production and among energy goods on a macro level, technical/engineering limits to substitution on a micro level, as well as engineering and behavioural limits on what can be achieved with increased efficiencies. We therefore support the call to develop integrated energy-economic systems dynamic models that are able to provide new insight into the nature of energy-economic transitions","PeriodicalId":15666,"journal":{"name":"Journal of Energy in Southern Africa","volume":"4 1","pages":"27-36"},"PeriodicalIF":0.0,"publicationDate":"2018-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89843615","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 : 2018-12-03DOI: 10.17159/2413-3051/2017/V29I4A5399
Steve Mvili-Gampio, L. Snyman
The objective of this study was to design a small-scale photovoltaic system to support electricity supply to a rural village in the Republic of Congo. A simple impedance-matching system and an innovative panel-tilting system were implemented as adaptive technologies to increase the power output of the system and reduce its capital and running costs. The experimentally obtained results showed that the daily energy output of a four-panel, 400 W photovoltaic system could be increased by 15% through a series parallel impedance match configuration, and by 36% from 3.3 kWh per day to approximately 4.5 kWh per day through implementing an automated panel tilting system with always normal incidence of solar irradiation on the panels in an equatorial environment. Implementing these technologies accordingly reduced the cost of energy supplied by the same percentages, with an eventual electricity cost of about ZAR 3.60 per kWhr, as calculated over an operation time of ten years, and an initial capital outlay of ZAR 37 per watt. These costs are much lower than for installing power grid lines to the village, and the technology also ensures complete autonomy of power supply to the community. The study also identified the potential to generate many new business and job opportunities locally in this community, as well as in the rest of Africa.
{"title":"Developing a small photovoltaic power supply system with adaptive technologies for rural Africa: Design, cost and efficiency analyses","authors":"Steve Mvili-Gampio, L. Snyman","doi":"10.17159/2413-3051/2017/V29I4A5399","DOIUrl":"https://doi.org/10.17159/2413-3051/2017/V29I4A5399","url":null,"abstract":"The objective of this study was to design a small-scale photovoltaic system to support electricity supply to a rural village in the Republic of Congo. A simple impedance-matching system and an innovative panel-tilting system were implemented as adaptive technologies to increase the power output of the system and reduce its capital and running costs. The experimentally obtained results showed that the daily energy output of a four-panel, 400 W photovoltaic system could be increased by 15% through a series parallel impedance match configuration, and by 36% from 3.3 kWh per day to approximately 4.5 kWh per day through implementing an automated panel tilting system with always normal incidence of solar irradiation on the panels in an equatorial environment. Implementing these technologies accordingly reduced the cost of energy supplied by the same percentages, with an eventual electricity cost of about ZAR 3.60 per kWhr, as calculated over an operation time of ten years, and an initial capital outlay of ZAR 37 per watt. These costs are much lower than for installing power grid lines to the village, and the technology also ensures complete autonomy of power supply to the community. The study also identified the potential to generate many new business and job opportunities locally in this community, as well as in the rest of Africa.","PeriodicalId":15666,"journal":{"name":"Journal of Energy in Southern Africa","volume":"16 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81668582","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}
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