Scielo RSS <![CDATA[Journal of Energy in Southern Africa]]> http://www.scielo.org.za/rss.php?pid=1021-447X20180001&lang=pt vol. 29 num. 1 lang. pt <![CDATA[SciELO Logo]]> http://www.scielo.org.za/img/en/fbpelogp.gif http://www.scielo.org.za <![CDATA[<b>Mitigating interference from switch-mode power supplies in sampling receivers</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S1021-447X2018000100001&lng=pt&nrm=iso&tlng=pt The research and development preliminaries, which led to an opportunity to embark on the present study took place during the system testing phase of a frequency-modulated continuous wave (FMCW) radar at Reutech Radar Systems, when a large false target was observed emerging on the range-Doppler map. The first indication was that the problem originated from interference caused by the switch-mode power supply (SMPS), which supplies direct current power to the radar receiver subsystem. This created the need for a new DC power supply, which was able to minimise the interference itself and mitigate the effects of the interference caused by the switching of the power supply. The present study is based on the research and development of techniques to mitigate interference from SMPS in sampling receivers, with emphasis on FMCW radar receiver applications. The study was divided into four main sections: research, simulation, design and evaluation. The research involved obtaining background information on sampling receivers, sampling theory, range-Doppler processing, SMPS, their effects, and mitigating these. This research section was utilised to simulate the various interference mitigation techniques, while a power supply printed circuit board (PCB) was established in the design phase to practically illustrate the techniques being utilised. Lastly, during evaluation, this PCB was evaluated against the criteria set out in the research phase. The results demonstrated that the techniques of synchronising the pulse width modulation clock to the sampling frequency and sweep repetition frequency yielded a significant reduction in the SMPS noise on the range-Doppler map. This technique may also be applied in other electronic sampling systems which perform digitisation of the input data, such as analogue-to-digital converters. <![CDATA[<b>Tracking decarbonisation in the mining sector</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S1021-447X2018000100002&lng=pt&nrm=iso&tlng=pt Greenhouse gas (GHG) emissions increase as mining companies transport ore over increased distances in opencast operations or extract ore from deeper levels in underground operations. The rising costs of energy sources and enhanced awareness of the impacts of GHG emissions support energy- and emission-reduction initiatives. This paper evaluates the metrics used in GHG emissions projections and target-setting over a ten-year period from 2005, linked to the South African Energy Efficiency Accord. The GHG inventories of a gold- and iron ore-mining company, together with the implemented energy saving projects, were analysed to evaluate progress against targets. A broad target value, defined as a percentage reduction of GHG emissions over time, was found to be problematic in monitoring performance over time. A direct link between emissions and output metrics was not found, due to external factors, such as the impact of changes in the grid emission factor, acquisitions and divestments, and internal factors, including changes in ore grade or mining depth. Using a metric linked to the activity within the operations, such as total tonnes mined, is, therefore, more appropriate for mining companies than production output. A methodological tool, using both the inventory and the savings from implemented mitigation initiatives, is proposed to improve GHG emissions projections, establishing a counterfactual baseline, and to support target setting. Decarbonisation of the mining industry would require careful review of the metrics to project and set GHG reduction targets. HIGHLIGHTS: • Decarbonisation metrics of the mining sector should be reviewed. • Learn from 2005 targets, for setting credible new targets. • Emission reductions should be reported, together with GHG inventory. • Best metrics use mining activity, and not mining output. <![CDATA[<b>Addressing fragmentation in the South African renewable energy governance effort - lessons to be learnt from France</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S1021-447X2018000100003&lng=pt&nrm=iso&tlng=pt The drive towards increased renewable energy generation and its application in South Africa are codified in a variety of policy documents and pieces of legislation, which together embody the national renewable energy legal framework. In many instances these legal instruments differ in terms of the nature of the field of law influencing their objectives and the governmental department of their origin. This situation is generically labelled as fragmentation and is widely seen as a hindrance to the achievement of the Constitutional objective of promoting sustainable development in South Africa. By necessary implication, integration is proposed as the solution to fragmentation and it is in this regard that this study puts forward the French approach to legal and institutional integration as a possibility for South Africa. The study presents the French energy transition legal framework for consideration by the South African legislature as a potential roadmap towards a more holistic and integrated renewable energy governance effort. In pursuing this objective, the study discusses the suitability of the French approach in the South African context and concludes that a hybrid of the French governance framework could fruitfully be applied locally. <![CDATA[<b>Community acceptance challenges of renewable energy transition: A tale of two solar parks in Limpopo, South Africa</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S1021-447X2018000100004&lng=pt&nrm=iso&tlng=pt Severe problems of climate change, inequality, poverty, and unemployment have compelled the South African government to pass legislation that introduced programmes aimed at achieving energy security, promoting economic development, and realising environmental protection. The Renewable Energy Independent Power Producers Procurement Programme objective is to increase the share of renewable sources in the national energy mix, deliver jobs and economic empowerment for black communities (Africans, Coloureds, and Indians) and cut harmful greenhouse gas emissions. Independent power producers (IPPs) must demonstrate that their projects contribute to job creation and broad-based black economic empowerment during the bidding process. To date, studies suggest that IPPs are missing this government target. This study investigated this phenomenon through face-to-face interviews with key informants involved in the IPP process at two solar parks in Limpopo province. Qualitative content analysis was used to analyse and interpret the field notes. Findings reveal that the process of involving local communities in the governance of the IPP process is highly fragmented, leaving room for powerful stakeholders to thrive over vulnerable community members. The lack of monitoring by the government IPP office enables a prominent not-forprofit organisation to abscond from its responsibility of setting up a community trust for the benefit of local residents. Also, limited skills in the local communities mean that young people are employed in low-paying construction jobs that end after project commissioning. Lack of awareness and knowledge about IPP commitments made during the bidding process are responsible for the 'wait and see' approach of local leaders and community members. In the short-term, awareness and capacity-building interventions for local leaders and community members are urgently required to conscientise beneficiaries. It is imperative to create a participatory governance framework that prioritises vulnerable stakeholders as a long-term solution. <![CDATA[<b>The impact of a fuel levy on economic growth in South Africa</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S1021-447X2018000100005&lng=pt&nrm=iso&tlng=pt Government expenditure is one of the factors that could influence economic growth and it depends on borrowing or on the amount of tax revenue. A fuel levy, as an excise tax charged on petroleum products such as petrol, diesel and biodiesel, can be an important source of revenue for the government. It can, however, be a burden on fuel consumers. The present study, as an effort to address this controversy, used the vector autoregressive approach to examine the impact of fuel levies on economic growth in South Africa. The results showed a longrun unidirectional negative relationship between economic growth and fuel levy. The conclusion was that the economy needs to grow at a higher rate so as to boost tax revenues and public expenditure. Strong revenue collection, therefore, depends on highly increasing economic growth and efficient tax administration. The implication of a growth-oriented tax system is to minimise distortions created by the tax system and create incentives for drivers of economic growth. <![CDATA[<b>Green economy in the wastewater treatment sector: Jobs, awareness, barriers, and opportunities in selected local governments in South Africa</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S1021-447X2018000100006&lng=pt&nrm=iso&tlng=pt The green economy (GE) has increasingly gained international focus, with new strategies aimed at restructuring the economy in an environmentally friendly manner. A study was carried out to analyse existing and potential green jobs and identify green qualifications and skills necessary for the development of the GE. The study was done within the context of the role of local governments in the adoption of green economy strategies in the wastewater treatment sector, in selected local governments across the northern provinces of South Africa. A descriptive survey method with qualitative and quantitative approaches was employed for data collection from twenty-four wastewater treatment plants in eleven local municipalities. The concept of the GE was foreign to several employees, who could not identify green jobs within most sectors of the economy. Only13.5% of the employees of the surveyed plants were involved in directly green jobs. A further 36% were in green-related jobs while the remaining 50.5% were involved in non-green jobs. Barriers to the creation of green jobs and implementation of green practices were the shortage of employees with green and conventional wastewater treatment skills, and lack of training in green skills. Several opportunities for green jobs creation exist, such as the implementation of renewable energy, re-use of treated effluent, and processing of waste sludge into compost. To spur GE growth and create green jobs, the creation of awareness, development of skills and implementation of green technologies should be intensified. <![CDATA[<b>Wind power variability and power system reserves in South Africa</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S1021-447X2018000100007&lng=pt&nrm=iso&tlng=pt Variable renewable generation, primarily from wind and solar, introduces new uncertainties in the operation of power systems. This paper describes and applies a method to quantify how wind power development will affect the use of short-term automatic reserves in the future South African power system. The study uses a scenario for wind power development in South Africa, based on information from the South African transmission system operator (Eskom) and the Department of Energy. The scenario foresees 5% wind power penetration by 2025. Time series for wind power production and forecasts are simulated, and the duration curves for wind power ramp rates and wind power forecast errors are applied to assess the use of reserves due to wind power variability. The main finding is that the 5% wind power penetration in 2025 will increase the use of short-term automatic reserves by approximately 2%. Highlights • Simulations are validated against observations of 30 minutes ramp rates. • Absolute wind power ramp rates increase from 2014 to 2025. • Normalised wind power ramp rates decrease from 2014 to 2025. • Wind power will not impact the use of instantaneous reserves. • Wind power will increase use of regulating reserves with less than 3% in 2025.