Scielo RSS <![CDATA[Journal of Energy in Southern Africa]]> http://www.scielo.org.za/rss.php?pid=1021-447X20180004&lang=es vol. 29 num. 4 lang. es <![CDATA[SciELO Logo]]> http://www.scielo.org.za/img/en/fbpelogp.gif http://www.scielo.org.za <![CDATA[<b>Design and performance evaluation of wood-burning cookstoves for low-income households in South Africa</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S1021-447X2018000400001&lng=es&nrm=iso&tlng=es Many cookstove programmes implemented around the world aimed to reduce fuel consumption and pollutant emissions through the dissemination and adoption of improved cookstoves. A study was carried out for the design of wood-burning cookstoves for low-income households in South Africa by employing user-centred design and co-design/co-creation approaches. Six designed variants of the biomass stove were constructed. Water-heating and emissions tests, using black wattle wood, were conducted to evaluate them for thermal and emissions performance. The large hopper stove with two secondary air inlets ranked highest, with best performance regarding thermal and emissions parameters. It outperformed the small hopper stove in time to boil, heat flux and firepower, although the latter had higher thermal efficiency values. Fuel consumption rates were high in large hopper stoves compared with small hopper stoves, resulting in increased firepower. The experimental work showed the need for iterative designing and testing of cookstoves for emissions and thermal performance to identify efficient and less polluting candidate stoves for dissemination in low-income communities. Highlights • Design and development of an efficient wood-burning stove • User-centred design and co-design/ co-creation were employed • Large hopper stoves had better thermal and emissions performance • Recommendations for contextual testing of the candidate stove <![CDATA[<b>Experiences with improved cookstoves in Southern Africa</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S1021-447X2018000400002&lng=es&nrm=iso&tlng=es This study explores user experiences with improved cookstoves, drawing on findings from household surveys conducted in South Africa, Mozambique, Malawi and Zambia. Investigations were conducted on fuel and stove preferences; experiences with improved biomass cookstoves; the rationale for fuel and stovestacking subsequent to the initial uptake of improved biomass cookstoves; and aspirations for energy and fuel use among improved biomass cookstove users. Significant differences were identified in the perceived benefits of improved biomass cookstoves in the four countries and their priorities, with the most important benefits being fuel and cost savings. These would affect the reference frames within which end-users adopt improved biomass cookstoves. Local circumstances and diverse sets of priorities that affect household decisions need to be considered when promoting or rolling out improved cookstove initiatives. <![CDATA[<b>An overview of salient factors, relationships and values to support integrated energy-economic system dynamics modelling</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S1021-447X2018000400003&lng=es&nrm=iso&tlng=es Integrated energy-economic modelling is needed to support the development of energy and climate policies. This study asserts that it is important to consider a system dynamics modelling approach that includes dynamics, endogenous treatment of uncertainty and risks, and both aggregate economic and disaggregate technical or engineering levels of analysis. The study examined the economic growth and the factors of production, elasticities, macroand technical substitutability; energy cost shares, heat engine efficiencies and energy services efficiencies. Emphasis was laid on the support of the future development of integrated energy-economic models covering (a) the key factors or components; (b) the relationships among these components; (c) a quantification of parameters; and (d) the implications for the development of an integrated energy-economic system dynamics model. The study suggested the following: a non-linear relationship in production and consumption; large variations among price and income elasticity values across time frames, across countries and regions, and across energy goods; a 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; and engineering and behavioural limits on what can be achieved with increased efficiencies. The study argues that integrated energy-economic modelling intensifies the accounting for the factors, relationships, quantifications, and implications, and that this practice allows for such models to describe a complex, emergent energy-economic reality that informs better energy policy. Highlights • Integrated energy-economic modelling needs to include physical and economic aspects. • Such models need to build on empirically verifiable relationships among key factors. • The main factors and interrelationships for energy-economic systems were developed. • Key factors identified are production, elasticities, substitutability (macro- and technical), energy cost share, heat engine efficiency, and energy services efficiency. <![CDATA[<b>System adequacy in the Southern African Power Pool: A case for capacity mechanisms</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S1021-447X2018000400004&lng=es&nrm=iso&tlng=es 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. Highlights • Increased investment in electrical energy infrastructure in the SAPP region is needed to enable increased electricity access and economic growth. • The SAPP region has exhibited historical sustained system inadequacy and distinctive investment cycles. • Competitive electricity trade is increasing and displacing bilateral contacts. • An appropriately designed capacity mechanism for SAPP could facilitate system adequacy and incentivise long-term capacity investment. <![CDATA[<b>The vulnerability of the South African electricity transmission network infrastructure to weather and climate: A review</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S1021-447X2018000400005&lng=es&nrm=iso&tlng=es 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 extreme 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 of weather-energy partnerships 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. <![CDATA[<b>Developing a small photovoltaic power supply system with adaptive technologies for rural Africa: Design, cost and efficiency analyses</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S1021-447X2018000400006&lng=es&nrm=iso&tlng=es The objective of this stud]; 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 often 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. <![CDATA[<b>Energy flow estimation-control of two interconnected microgrids</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S1021-447X2018000400007&lng=es&nrm=iso&tlng=es Being dependent on weather, photovoltaic and wind system energy contributions fluctuate and are not continuously available, and sometimes not in the desired quantity. To avoid load shedding or blackout in this situation, the estimation-control of energy can be useful to ensure continuity of supply and assist the planning operation of the power system. This study proposes the estimation-control of the flow of energy between two microgrids interconnected via two alternating current tie-lines. Two sources of power generation depending on weather behaviours have been considered. The effectiveness of the proposed estimation-control model was shown using the Extended Kalman filter combined with the fmin-con algorithm.