Journal of Energy in Southern Africa https://journals.assaf.org.za/index.php/jesa <p>The <em>Journal of Energy in Southern Africa (JESA)</em> is published by the&nbsp;<a href="http://www.erc.uct.ac.za/" target="_blank" rel="noopener">Energy Research Centre</a> and offers mostly papers covering the technical, economic, policy, environmental and social aspects of energy research and development carried out in, or relevant to, South Africa.</p> en-US <p>Copyright remains with the author(s).</p> <p>Publishing rights remain with the author(s)</p> <p>All articles published in JESA can be re-used under the following CC license:&nbsp;CC BY-SA&nbsp;<a href="http://creativecommons.org/licenses/by-sa/4.0/" target="_blank" rel="license noopener">Creative Commons Attribution-ShareAlike 4.0 International License</a>.</p> mok.roberts@uct.ac.za (Mokone J. Roberts) mok.roberts@uct.ac.za (Mokone J. Roberts) Fri, 22 Jun 2018 09:10:13 +0000 OJS 3.1.1.2 http://blogs.law.harvard.edu/tech/rss 60 A review of private investment in Tanzania’s power generation sector https://journals.assaf.org.za/index.php/jesa/article/view/4389 <p>This study investigates recent developments in Tanzania’s electric power generation to understand how to facilitate investment in the sector. Interviews were conducted with key public and private stakeholders; utility data was analysed and critical secondary source documents were reviewed. All interview data was triangulated to ensure integrity of findings. It was concluded that investment in the sector is suboptimal due to a lack of coherent planning; of processes related to contract negotiation; and of a commitment to contract with independent power projects. Research and analysis is limited to generation, but there are also implications for the distribution sector. The value of the findings extends beyond Tanzania across Africa and to other developing regions, where countries struggle to attract investment into electric power generation.</p> Anton Eberhard, Katharine Gratwick, Laban Kariuki ##submission.copyrightStatement## http://creativecommons.org/licenses/by-sa/4.0 https://journals.assaf.org.za/index.php/jesa/article/view/4389 Fri, 22 Jun 2018 00:00:00 +0000 The performance of split and integrated types of air-source heat pump water heaters in South Africa https://journals.assaf.org.za/index.php/jesa/article/view/4358 <p>Renewable energy technologies that can provide optimum and cost-effective energy savings to mitigate global warming, energy crisis and to achieve energy efficiency continue to be of paramount importance. The present study focused on identifying critical parameters such as the volume of hot water drawn off; ambient temperature; relative humidity; refrigerant temperatures at the inlet and outlet of the compressor and condenser; and deterministic quantities such as time used, power consumption and coefficient of performance (COP) as indicators to benchmark the performance of both the split and integrated types of air-source heat pump (ASHP) water heaters. The basis for analysis was on two predominant scenarios: first-hour heating rating and the heating cycle due to controlled volume of hot water drawn-off wherein both the integrated and split types ASHP water heaters experienced vapour compression refrigeration cycles. A data acquisition system was constructed and implemented to monitor the performance of both systems. The results obtained during summer season showed that, under the scenario of 150 L hot water withdrawal, the average COP of the systems was 3.18 and 2.85 for the split and integrated types respectively. The average power consumed was 1.29 (split type) and 0.85 kW (integrated type). The times of operation were 84 minutes (split type) and 138 minutes (integrated type).</p> Stephen Loh Tangwe, Michael Simon, Russel Mhundwa ##submission.copyrightStatement## http://creativecommons.org/licenses/by-sa/4.0 https://journals.assaf.org.za/index.php/jesa/article/view/4358 Fri, 22 Jun 2018 00:00:00 +0000 Wind energy in South Africa: A review of policies, institutions and programmes https://journals.assaf.org.za/index.php/jesa/article/view/1433 <p>South Africa is promoting renewable energy such as wind power to address the objectives of both energy security and sustainable development. This paper reviews the nature of policies, institutional set-up and programmes in place to upscale especially onshore wind energy uptake, as reflected in publicly available documents. It shows that South Africa has put in place critical policies, institutions and programmes for wind energy uptake. Among key policy documents and policies are the White Paper on Energy (1998), Renewable Energy White Paper (2003), Energy Act of 2008, and National Climate Change Response White Paper (2011). There is also the Integrated Energy Plan, the Integrated Resource Plan (2010, revised 2013) and Environmental Impact Assessment Guidelines for Renewable Energy Projects of 2015. Key institutions noted include the South African National Energy Development Institute, the South African Renew-able Energy Council and the South African Wind Energy Association. The main programme is the Renewable Energy Independent Power Producers Procurement Programme, which resulted in more than 30 installed wind energy projects. Overall, wind energy promises to be among the viable and acceptable technologies in the renewable energy sector in South Africa.</p> Chipo Mukonza, Godwell Nhamo ##submission.copyrightStatement## http://creativecommons.org/licenses/by-sa/4.0 https://journals.assaf.org.za/index.php/jesa/article/view/1433 Fri, 22 Jun 2018 00:00:00 +0000 Providing a foundation for road transport energy demand analysis: The development of a vehicle parc model for South Africa https://journals.assaf.org.za/index.php/jesa/article/view/2774 <p>Abstract<br>It is key for national economic planning to build the tools to forecast energy demand from major sectors like transport in a credible way. As a starting point, this requires building a sufficiently detailed ‘bottom-up’ picture of technologies and their activity levels in the recent past. A vehicle parc model was developed for South Africa to feed transport demand and data on the fleet into a national energy systems model, the South African TIMES model, which is a least-cost optimisation model of the TIMES/ MARKAL family. Detailed assumptions were developed for 24 vehicle typologies that included the vintage profile, annual mileage and its relationship with age, fuel economy and its improvement over time, and occupancy and load factor. Combining these assumptions, the model was successfully calibrated over 2000–2014 with the national registration database, national fuel sales statistics and, on the freight side, with estimates of the demand for ton.km published by the University of Stellen-bosch’s Department of Logistics (2014 only). A demand for passenger.km was also calculated, which agreed well with national transport surveys. A range of detailed indicators were produced for the vehicle typologies and some interesting trends observed, including the steady dieselisation of the light vehicle fleet over the study period and the stagnation of passenger car fuel economy, despite legislation in the European Union. The present study believes that this updated data-rich picture of the road transport vehicle parc will support other studies and national policy and planning initiatives.</p> Adrian Stone, Bruno Merven, Tiisetso Maseela, Resmun Moonsamy ##submission.copyrightStatement## http://creativecommons.org/licenses/by-sa/4.0 https://journals.assaf.org.za/index.php/jesa/article/view/2774 Fri, 22 Jun 2018 00:00:00 +0000 The agglomeration of coal fines using wet microalgae biomass https://journals.assaf.org.za/index.php/jesa/article/view/3469 <p>South African coal generally contains a high percentage of non-carbon mineral matter, which necessitates processing to remove the bulk of the non-carbon material. Such processing results in the formation of some 60 million tons of discard coal and between four and eight million tons of very fine, unusable coal, called ultra-fines, each year. The objective of this study was to investigate factors that impact on the agglomeration of fine coal of &lt;150 mm when using microalgae biomass as the sole binder. Mixtures of coal and wet microalgae biomass were prepared and pelletised. The proximate properties of the mixtures and coal were determined and the physical properties of the pellets measured, such as compression strength, water resistance and impact resistance. The results showed that pelletisation of Coalgae® is a promising technology for the recovery of coal fines. Moisture content, pressure and holding time influence the quality of the pellets. Compression resistance testing indicated that pellets made from the coal80%-algae20% (by weight) mixture were stronger than those made from the coal90%-algae10% (by weight) mixture. Pellets made from samples with ± 17% moisture content exhibited the strongest resistance, one of 1.8 kg/mm2 for the coal80%-algae20% mixture that was centrifuged after 24 hours. The water resistance index for all the pellets was lower than the recommended 95%, which was considered to put emphasis on handling, transportation and storage of the pellets.</p> Sibongiseni Gloria Gaqa, Paul Watts ##submission.copyrightStatement## http://creativecommons.org/licenses/by-sa/4.0 https://journals.assaf.org.za/index.php/jesa/article/view/3469 Fri, 22 Jun 2018 00:00:00 +0000 Cluster analysis for classification and forecasting of solar irradiance in Durban, South Africa https://journals.assaf.org.za/index.php/jesa/article/view/4338 <p>Clustering of solar irradiance patterns was used in conjunction with cloud cover forecasts from Numerical Weather Predictions for day-ahead forecasting of irradiance. Beam irradiance as a function of time during daylight was recorded over a one-year period in Durban, to which k-means clustering was applied to produce four classes of day with diurnal patterns characterised as sunny all day, cloudy all day, sunny morning-cloudy afternoon, and cloudy morning-sunny afternoon. Two forecasting methods were investigated. The first used k-means clustering on predicted daily cloud cover profiles. The second used a rule whereby predicted cloud cover profiles were classified according to whether their average in the morning and afternoon were above or below 50%. In both methods, four classes were found, which had diurnal patterns associated with the irradiance classes that were used to forecast the irradiance class for the day ahead. The two methods had a comparable success rate of about 65%; the cloud cover clustering method was better for sunny and cloudy days; and the 50% rule was better for mixed cloud conditions.</p> Paulene Govender, Michael J. Brooks, Alan P. Matthews ##submission.copyrightStatement## http://creativecommons.org/licenses/by-sa/4.0 https://journals.assaf.org.za/index.php/jesa/article/view/4338 Fri, 22 Jun 2018 00:00:00 +0000 Comparison of satellite-retrieved high-resolution solar radiation datasets for South Africa https://journals.assaf.org.za/index.php/jesa/article/view/3376 <p><span lang="EN-US"><span style="font-family: Arial; font-size: small;">This study compares the performance of two satellite-based solar radiation methodologies for estimating the solar resource available in South Africa. Data from thirteen stations distributed in six climatic regions were considered. More than one year of hourly values of global horizontal and beam normal irradiance were examined in the validation of the satellite-retrieved estimates at every location. The best satellite method resulted in an overall relative mean bias of 1.41% for the global horizontal irradiance corresponding to almost 3 Wm<sup>-2</sup> and exhibited a relative mean bias of 2.85% for the beam normal irradiance estimation (about 7 Wm<sup>-2</sup>). This satellite-based method was implemented into a geographical information system module, which contained high-resolution terrain data and allowed the effect of the surrounding topography on the estimation of the available solar resource to be considered. These estimates can, therefore, be used as input data for further analysis or applications. As an example, maps of the potential output that could be expected in South Africa from photovoltaic systems were created.</span></span></p> Ana Gracia Amillo, Lucky Ntsangwane, Thomas Huld, Jörg Trentmann ##submission.copyrightStatement## http://creativecommons.org/licenses/by-sa/4.0 https://journals.assaf.org.za/index.php/jesa/article/view/3376 Fri, 22 Jun 2018 09:04:44 +0000 Investigating seasonal wind energy potential in Vredendal, South Africa https://journals.assaf.org.za/index.php/jesa/article/view/2746 <p>Global warming and the energy crisis have necessitated an urgent exploitation and utilisation of renewable energy. Wind energy has gained popularity over the years because of vast availability of its resource. A study was carried out to investigate the stochastic characteristics of the available wind energy at installation sites. Data for a ten-minute interval wind speed collected over a period of five years and measured at a height of 10, 40 and 62 m in Vredendal was considered. Wind speed data was arranged in seasonal format and its statistical distribution investigated based on Weibull, lognormal and gamma distributions. The Anderson-Darling test and Akaike information criterion were used to evaluate the goodness of fit. The results showed that wind power at different heights and time stamps exhibited different statistical distribution. It was found that wind turbines in Vredendal must be installed as high as possible to harness wind power effectively. During summer and spring, there was a high potential for wind power availability compared with that of winter.</p> Thapelo Cornelius Mosetlhe, Adedayo Ademola Yusuff, Yskandar Hamam ##submission.copyrightStatement## http://creativecommons.org/licenses/by-sa/4.0 https://journals.assaf.org.za/index.php/jesa/article/view/2746 Fri, 22 Jun 2018 00:00:00 +0000 Recommendations for the energy efficiency technology landscape in South Africa https://journals.assaf.org.za/index.php/jesa/article/view/4910 Roseanne Diab ##submission.copyrightStatement## http://creativecommons.org/licenses/by-sa/4.0 https://journals.assaf.org.za/index.php/jesa/article/view/4910 Fri, 22 Jun 2018 10:00:28 +0000