Power Plants In South Africa Research Articles

Selenium quantification in wastewaters from selected coal-fired power plants and river waters in South Africa using ICP-MS

South Africa mainly relies on Eskom's coal-fired power plants for electricity generation. However, the use of coal causes several adverse environmental impacts, including the release of selenium into the hydrosphere. Selenium is an essential nutrient for humans, animals, and microbes, but excess selenium is toxic. This paper describes the determination of total dissolved selenium in wastewater from selected coal-fired power plants and river waters near coal-fired power plants in South Africa. A sensitive and robust inductively coupled plasma mass spectrometry (ICP-MS) method for determining total dissolved selenium in wastewater and river water was developed using a certified reference material (NIST SRM 1640a Trace Elements in Natural Water). The results agreed with the certified values, with percentage recoveries ranging from 92–96%. The method detection limit was 0.13 µg/L. Total Se concentrations in wastewater samples from Kriel and Lethabo Power Stations ranged between 4.86 and 8.53 µg/L, and in river water samples from the Olifants and Wilge Rivers, the concentrations ranged from 2.63–8.20 µg/L. These results indicate that the Se levels in the wastewater are too low to pose a health hazard to humans and livestock but pose an environmental threat to aquatic life. The low concentrations in the river samples also show that there may be slight Se pollution (regarding aquatic life) from the selected coal-fired power plants in South Africa. There may be slight Se pollution (with regards to aquatic life) from Duvha and Kendal Power Stations because an increase from 2–8 µg/L was observed in river water samples collected near these selected coal-fired power plants.

Incentive-oriented economic statecraft by Russia in the nuclear energy sector of democratic countries

ABSTRACT The literature on incentive-oriented economic statecraft, specifically its so-called domestic conditionalist strand, identifies the political arrangements in the target state as a primary factor in the success or failure of the sender state’s economic statecraft. Drawing on existing literature, this article on Russia’s economic statecraft in democratic countries focuses on the nuclear energy sector, arguing that democratic backsliding in target states might provide a window of opportunity for Moscow. The effectiveness of Russia’s state-owned nuclear energy company, Rosatom, in building nuclear power plants in South Africa, Hungary, the Czech Republic, and Finland is assessed in this article.

Using liquefied petroleum gas to reduce the operating cost of the Ankerlig peaking power plant in South Africa

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.

Determinants of Successful Coaching Outcomes: Case Review of Eskom’s Matla Power Plant, South Africa

Workplace health and safety is an important aspect of the success of organisations as it considers the well-being of both employees and the company. Present research is based on the impact of coaching on a perception of developing a health and safety culture. In this regard, the qualitative study has been conducted to assess the role of coaching in developing the health and safety culture for Eskom’s Matla power plant in South Africa which is prone to workplace risk. The outcomes of the study are based on both the primary and secondary data wherein 20 middle managers of four plants of Eskom’s Matla have been selected. The analysis brought forth the outcome that coaching is the effective way to provide the practical experience related to a health and safety environment among new employees. However, existing managers faced the issue of consumption of time in coaching and workload. Subsequently, it was found that coaching makes it easy for the business to reduce the gap between employees and management which leads to set the safety culture in the right manner and to reduce the risk. Coaching can therefore be provided for adopting the changes in the current practices of imparting knowledge to employees and for enabling them to support the organisation to ensure its long-run survival.

Bioenergy potential from invasive alien plants: Environmental and socio-economic impacts in Eastern Cape, South Africa

South Africa's natural resources and ecosystems are negatively affected by Invasive Alien Plants (IAPs). We used a life-cycle approach to assess the environmental and socio-economic impacts of using IAPs for electricity generation in South Africa or exported and used for electricity generation in the Netherlands. Supply chain greenhouse gas (GHG) emissions of electricity from IAPs pellets, excluding land use change-related GHG emissions, are 31.5 gCO2eq MJ−1 for electricity generation in South Africa and 31.2 gCO2eq MJ−1 for electricity generation in the Netherlands. An additional 3.9 gCO2eq MJ−1 is accounted for if emissions of land use change are included and land is rehabilitated to its natural state. The removal of IAPs results in water savings when considering any potential land use transition, ranging between 1,263 mm year−1 for annual cropland to 12 mm year−1 for dense forest. The supply chain costs of pellets are 5,344 ZAR Mg−1 (285 € Mg−1) delivered at the power plant in South Africa and 2,535 ZAR Mg−1 (159 € Mg−1) delivered at Rotterdam port. Direct full-time jobs generated from removing IAPs up to the conversion-factory-gate are 604 FTE year−1 for South Africa and 525 FTE year−1 for the Netherlands. There are clear trade-offs between environmental and social benefits and costs. There are generally net carbon losses when considering the land use transitions after IAP removal, even when land is rehabilitated to its natural state. Using IAPs for electricity can be a valuable strategy for South Africa to generate employment, conserve water resources and reduce GHG emissions.

Physical, Chemical and Geotechnical Characterization of Wet Flue Gas Desulfurization Gypsum and Its Potential Application as Building Materials

In South Africa, coal represents the primary source of energy used for electricity generation. Coal power plants use the wet flue gas desulfurization (WFGD) process to remove sulfur dioxide (SO2) from their flue gas. However, this technology produces a large amount of synthetic gypsum, resulting in waste disposal and environmental pollution. This study investigated the physical, chemical and geotechnical properties of WFGD gypsum and its potential application to develop cement-free bricks. WFGD gypsum was collected from a coal power plant in South Africa. It was found that the principal oxides of WFGD gypsum were sulfur trioxide (SO3) and calcium oxide (CaO), which represented more than 90% of the total weight. Calcium sulfate (CaSO4) and calcium di aluminate (CA2) were the predominant minerals in the raw material. The density of the WFGD gypsum was 2.43 g/cm3. The maximum dry density and optimum moisture content values were 1425 kg/m3 and 18.5%, respectively. WFGD gypsum had a liquid limit of 51% but did not display any plasticity characteristics. The optimum curing temperature of gypsum bricks was 40 °C. WFGD gypsum-based bricks exhibited compressive strength of up to 2.3 MPa and a density of about 28% less than that of typical clay bricks. Additionally, there was no significant decrease in compressive strength after seven wet/dry cycles. These results show that WFGD gypsum could be used to produce lightweight building materials with low strength requirements.

Changes in risk factors for non-communicable diseases associated with the ‘Healthy choices at work’ programme, South Africa

ABSTRACT Background Globally 71% of deaths are attributed to non-communicable diseases (NCD). The workplace is an opportune setting for health promotion programs and interventions that aim to prevent NCDs. However, much of the current evidence is from high-income countries. Objective The aim of this study was to evaluate changes in NCD risk factors, associated with the Healthy Choices at Work programme (HCWP), at a commercial power plant in South Africa. Methods This was a before-and-after study in a randomly selected sample of 156 employees at baseline and 137 employees at 2-years. The HCWP focused on food services, physical activity, health and wellness services and managerial support. Participants completed questionnaires on tobacco smoking, harmful alcohol use, fruit and vegetable intake, physical activity, psychosocial stress and history of NCDs. Clinical measures included blood pressure, total cholesterol, random blood glucose, body mass index, waist circumference and waist-to-hip ratio. The 10-year cardiovascular risk was calculated using a validated algorithm. Sample size calculations evaluated the power of the sample to detect meaningful changes in risk factors Results Paired data was obtained for 137 employees, the mean age was 42.7 years (SD 9.7) and 64% were male. The prevalence of sufficient fruit and vegetable intake increased from 27% to 64% (p < 0.001), those meeting physical activity guidelines increased from 44% to 65% (p < 0.001). Harmful alcohol use decreased from 21% to 5% (p = 0.001). There were clinical and statistically significant improvements in systolic and diastolic blood pressure (mean difference −10.2 mmHg (95%CI: −7.3 to −13.2); and −3.9 mmHg (95%CI: −1.8 to −5.8); p < 0.001) and total cholesterol (mean difference −0.45 mmol/l (−0.3 to −0.6)). There were no significant improvements in BMI. Psychosocial stress from relationships with colleagues, personal finances, and personal health improved significantly. The cardiovascular risk score decreased by 4.5% (> 0.05). Conclusion The HCWP was associated with clinically significant reductions in behavioural, metabolic and psychosocial risk factors for NCDs.

Quantification of U, Th and specific radionuclides in coal from selected coal fired power plants in South Africa.

Most of South Africa’s energy is derived from the combustion of coal in pulverized coal-fired power plants (CFPP). However, when compared with the rest of the world, limited information regarding the main radioactive elements (U and Th) and specific radionuclides of interest (K40, Ra226 and Th232) from South African CFPP is available in the public domain. This paper aims to quantify the U, Th and specific radionuclides found in the coal used in selected South African CFPP in comparison to world averages found in literature. The U and Th concentrations were obtained by ICP-MS. The main radionuclides, K40, Ra226 and Th238, were quantified using gamma spectrometry. The U concentration and Th concentrations for the coal used in all the power plants was above the world average of 1.9 mg/kg and 3.2 mg/kg respectively. The coals with the highest Th content originated from the Mpumalanga power plant, while the U content in the Freestate power plant samples was the highest of the three. The concentrations of the K40 were between 88.43±10.75–110.76±8.92 Bq/kg, which are in-line with world averages of 4–785 Bq/kg. Similarly, the Ra226 and Th232 values were between 21.69±2.83–52.63±4.04 Bq/kg and 19.91±1.24–22.97±1.75 Bq/kg respectively, which are also in line with the world averages of 1–206 Bq/kg and 1–170 Bq/kg respectively. Radiological hazard indices such as radium equivalent (Raeq); external hazard index (Hex) and internal hazard index (Hin), that were estimated from these average radionuclide concentrations were less than the prescribed values found in literature. This indicated that no significant health risk was posed by the coal being used from these coal fields.

A methodology to constrain carbon dioxide emissions from coal-fired power plants using satellite observations of co-emitted nitrogen dioxide

Abstract. We present a method to infer CO2 emissions from individual power plants based on satellite observations of co-emitted nitrogen dioxide (NO2), which could serve as complementary verification of bottom-up inventories or be used to supplement these inventories. We demonstrate its utility on eight large and isolated US power plants, where accurate stack emission estimates of both gases are available for comparison. In the first step of our methodology, we infer nitrogen oxides (NOx) emissions from US power plants using Ozone Monitoring Instrument (OMI) NO2 tropospheric vertical column densities (VCDs) averaged over the ozone season (May–September) and a “top-down” approach that we previously developed. Second, we determine the relationship between NOx and CO2 emissions based on the direct stack emissions measurements reported by continuous emissions monitoring system (CEMS) programs, accounting for coal quality, boiler firing technology, NOx emission control device type, and any change in operating conditions. Third, we estimate CO2 emissions for power plants using the OMI-estimated NOx emissions and the CEMS NOx∕CO2 emission ratio. We find that the CO2 emissions estimated by our satellite-based method during 2005–2017 are in reasonable agreement with the US CEMS measurements, with a relative difference of 8 %±41 % (mean ± standard deviation). The broader implication of our methodology is that it has the potential to provide an additional constraint on CO2 emissions from power plants in regions of the world without reliable emissions accounting. We explore the feasibility by comparing the derived NOx∕CO2 emission ratios for the US with those from a bottom-up emission inventory for other countries and applying our methodology to a power plant in South Africa, where the satellite-based emission estimates show reasonable consistency with other independent estimates. Though our analysis is limited to a few power plants, we expect to be able to apply our method to more US (and world) power plants when multi-year data records become available from new OMI-like sensors with improved capabilities, such as the TROPOspheric Monitoring Instrument (TROPOMI), and upcoming geostationary satellites, such as the Tropospheric Emissions: Monitoring Pollution (TEMPO) instrument.

Life cycle cost profitability of biomass power plants in South Africa within the international context

South Africa's renewable energy programme has been widely considered a success. Biomass is one of the selected technologies, on which capacity and tariff caps are set in place. It is unclear whether the price caps allow for sufficient profits for private role-players. The aim of the study is to investigate the potential profit margins for biomass power plant companies entering the programme. Costs throughout the lifespan of the power purchase agreement were determined by using the Levelised Cost of Electricity (LCOE) metric. The method used cost inputs which were determined using a mixture of local and international indicators for three scenarios, the worst case (WC) scenario representing highest input costs, the most likely case (MLC) scenario representing median costs, and best case (BC) scenario representing lowest input costs. The results show that the WC, MLC and BC LCOE for biomass power plants in South Africa are 3.53 ZAR/kWh (0.235 USD/kWh), 1.30 ZAR/kWh (0.086 USD/kWh) and 0.78 ZAR/kWh (0.052 USD/kWh), respectively. In all three scenarios, the bulk of the cost constitute delivered fuel costs. Considering sales tariffs at ZAR1.475/kWh, profit margins for WC, MLC and BC scenarios were determined as −139%, 12% and 47%, respectively. These figures compare favourably with China, the United States of America, and Europe in general, opposed to Canada, where higher profit margins are achievable.

Power quality grid code compliance for renewable power plants in South Africa

The introduction of renewable generation to South Africa's grid has introduced challenges to the management and regulation of power quality (PQ). These have been addressed by establishing PQ compliance criteria in line with local circumstances and by the introduction of a Power Quality Guideline for renewable power plants (RPPs). A key challenge to RPPs has been meeting emission limits for harmonics. This has been addressed in South Africa's RPP Guideline by the development and introduction of a Group Harmonic Distortion limit which provides some flexibility to RPPs in making individual harmonic emission limits. The use of 95th percentile harmonic impedance envelopes is discussed and recommendations for impedance envelopes are made for different voltage levels within the South African Grid, based on actual network data. A lesson learnt is that using international standards and guidelines provides a starting point for compliance rules when introducing renewable generation. Developing countries that share economic and electricity network characteristics with South Africa should tailor the PQ rules and guidelines for RPPs to meet local conditions.

Russian Projects and Energy Cooperation in South Africa

The article discusses the problems and prospects for the development of a Russian nuclear power plants in South Africa, as well as other innovative energy projects in this country. Acute energy shortages in South Africa give Russia a unique chance to enter the African market and create a technological link between African countries and Russian innovations. An analysis of the political and economic situation in South Africa, as well as an assessment of the prospects for Russian business participation in the development of the South African energy sector were carried out using research conducted by the authors in South Africa in 2016, and interviews with Russian and South African civil servants and businesmen.

Trace metal enrichment observed in soils around a coal fired power plant in South Africa

A site assessment was conducted at a coal fired power plant in South Africa to determine whether surrounding soils were being enriched with trace metals resulting from activities at the power plant. It was found that deposition of fly ash from the flue stacks and the ash dump along with deposition of coal dust from the coal stock yard were the activities most likely to lead to such enrichment. Eighty topsoil samples were gathered and analysed for total metal content. Results were interpreted within the context of background values. It was found that concentrations of As, Cu, Mn, Ni and Pb exceeded local screening levels, but only As and Pb could be confidently attributed to anthropogenic intervention and actual enrichment.

Assessing the enrichment of heavy metals in surface soil and plant (Digitaria eriantha) around coal-fired power plants in South Africa

Nine metals (Fe, Cu, Mn, Ni, Cd, Pb, Hg, Cr, and Zn) were determined in soil and Digitaria eriantha plants within the vicinity of three coal power plants (Matla, Lethabo, and Rooiwal), using ICP-OES and GFAAS. The total metal concentration in soil ranged from 0.05 ± 0.02 to 1836 ± 70 μg g(-1), 0.08 ± 0.05 to 1744 ± 29 μg g(-1), and 0.07 ± 0.04 to 1735 ± 91 μg g(-1) in Matla, Lethabo, and Rooiwal, respectively. Total metal concentration in the plant (D. eriantha) ranged from 0.005 ± 0.003 to 535 ± 43 μg g(-1) in Matla, 0.002 ± 0.001 to 400 ± 269 μg g(-1) in Lethabo, and 0.002 ± 0.001 to 4277 ± 201 μg g(-1) in Rooiwal. Accumulation factors (A) of less than 1 (i.e., 0.003 to 0.37) at all power plants indicate a low transfer of metal from soil to plant (excluder). Enrichment factor values obtained (2.4-5.0) indicate that the soils are moderately enriched with the exception of Pb that had significant enrichment of 20. Geo-accumulation index (I-geo) values of metals indicate that the soils are moderately polluted (0.005-0.65), except for Pb that showed moderate to strong pollution (1.74-2.53).

Fly Ash Resistivity Profiling for South African Coal Fired Power Stations

Particulate emission is a major problem in industrial processes, mainly power plants that make use of coal as a primary source of energy. Stringent emissions limits, set by government organisations requires industries to conform to these limits to ensure that air quality is sustained and with minimum pollutant present. Electrostatic precipitators are typically used to filter and collect these particulate emissions. Fly ash resistivity is a primary parameter in the collection of particulate emissions, and there is a resistivity range at which electrostatic precipitator collection is most efficient and anything outside this range limits, their operation. High resistivity ash results in back-corona discharge, whilst low resistivity results in particle re-entrainment into the flue gas stream. The purpose of this paper is to investigate and obtain a fly ash resistivity profile for existing power plants in South Africa. Ash samples obtained from power plants are, tested making use of an ash-resistivity test oven, in accordance with IEEE Standard 548-1984. This paper discusses obtained experimental results, to determine the resistivity profile at which South African power plant electrostatic precipitators operate. The electrical efficiency of the electrostatic precipitator system is evaluated based on the obtained resistivity profiles.

Modeling of the rock bed thermal energy storage system of a combined cycle solar thermal power plant in South Africa

A thermocline-based rock bed thermal energy storage system potentially offers a cheap and simple way of achieving dispatchability in an air-cooled central receiver CSP plant. In order to efficiently match heliostat field size, storage dimensions, back-up fuel consumption and turbine sizes for non-stop power generation and economic feasibility, year-long power plant simulations have to be run. This paper focuses on the storage as the center of in- and outgoing thermal energy. The derived storage model has one spatial dimension which is justified by the high tube-to-particle diameter ratio and because yearly aggregated – and not momentary – values are of interest. A validation of the correlations with data from the literature shows acceptable agreement. Sensitivity analyses indicate that, due to low costs of the storage system, above certain minimum storage dimensions, the influence on energetic and monetary performance indicators is marginal. The calculated LCOE is in the range of 0.11–0.18EUR/kWh and in agreement with other studies on combined cycle CSP plants.

Application of the performance-goal based approach for establishing the SSE site specific response spectrum for new nuclear power plants in South Africa

Nuclear installation license holders in South Africa have become increasingly interested in the performance-goal based approach defined in the American Society of Civil Engineering Standard ASCE/SEI 43-05 for establishing the safe shutdown earthquake (SSE) site specific design response spectrum (SSRS) for new nuclear power plants. This approach has been adopted by the U.S. Nuclear Regulatory Commission (NRC) and has now been followed at more than 20 sites in that country. Quantitative performance goals are required when establishing seismic design basis parameters using the performance-goal based approach. However, the quantitative performance goals recommended in ASCE/SEI 43-05 were established based on country-specific operating experience and seismic probabilistic risk assessment (SPRA) applications conducted for existing plants designed and operated to meet specific safety criteria, set by a specific regulatory body. Whilst ASCE/SEI 43-05 provides enough flexibility for the selection of other user-specified quantitative performance goals, there is no guidance on how quantitative performance goals should be established in the absence of extensive operational experience accompanied by data derived from rigorous SPRA applications. This paper presents two practical approaches that can be used to provide a technical basis and to demonstrate the derivation of quantitative values of target performance goals when no data related to past and present operational experience exist to justify technical specifications.

Estimating the opportunity cost of water for the Kusile and Medupi coal-fired electricity power plants in South Africa

In South Africa, water is considered a limited source, not only because of the country’s arid nature, but also because of the relatively skew distribution of the resource and the fact that 98% of the resource is already allocated. Eskom, the South African electricity supplier, commenced with the construction of two new coal-fired power stations namely Kusile and Medupi. The question is: what is the opportunity cost of investing in these power stations from a water perspective? We do not argue here against the need for power plants and additional electricity generation capacity per se, but consider the opportunity cost of using this specific technology. We estimate the shadow price of water for different power generation technologies as an indicator of the opportunity cost of water. We apply a production function approach for a baseline case (coal-fired power generation using the Medupi and Kusile parameters), and four alternative technologies. The only alternative that performs worse than the baseline case is the traditional wet-cooling coal-fired power process. The baseline case, however, does show a high opportunity cost when compared to renewable alternatives (solar, wind and biomass) ranging from R0.66/kWh (biomass) to R0.83/kWh (solar) to R1.31/kWh (wind).

An improved robust model for generator maintenance scheduling

The maintenance schedule of generators in power plants needs to match the electricity demand and ensure the reliability of the power plants at a minimum cost of operation. In this article, a reliability criterion modified generator maintenance scheduling (MGMS) model is formulated with additions and modifications made to the classic generator maintenance scheduling (GMS) model. The MGMS model includes modified maintenance window constraints with some newly added constraints. A comparison is then made between the MGMS model and the classic GMS model when both models are applied to a 21-unit test system. The results show that the MGMS model gives more reliable solutions than the GMS model. Due to the reliable results of the reliability criterion MGMS model, a robust model using economic cost objective function is formulated. To illustrate the robustness of the formulated MGMS model, the maintenance of the Arnot Power Plant in South Africa is scheduled with open loop and closed loop controllers. Both controllers satisfy all the constraints but the closed loop results are better than the open loop results.

Distribution and potential sources of polycyclic aromatic hydrocarbons in soils around coal-fired power plants in South Africa

The distribution and potential sources of 15 polycyclic aromatic hydrocarbons (PAHs) in soils in the vicinity of three South African coal-fired power plants were determined by gas chromatography-mass spectrometry. PAH compound ratios such as phenanthrene/phenanthrene + anthracene (Phen/Phen + Anth) were used to provide reliable estimation of emission sources. The total PAH concentration in the soils around three power plants ranged from 9.73 to 61.24μgg(-1), a range above the Agency for Toxic Substances and Disease Registry levels of 1.0μgg(-1) for significantly contaminated site. Calculated values of Phen/Phen + Anth ratio were 0.48 ± 0.08, 0.44 ± 0.05, and 0.38 + 0.04 for Matla, Lethabo, and Rooiwal, respectively. Flouranthene/fluoranthene + pyrene (Flan/Flan + Pyr) were found to be 0.49 ± 0.03 for Matla, 0.44 ± 0.05 for Lethabo, and 0.53 ± 0.08 for Rooiwal. Such values indicate a pyrolytic source of PAHs. Higher molecular weight PAHs (five to six rings) were predominant, suggesting coal combustion sources. A good correlation existed between most of the PAHs implying that these compounds were emitted from similar sources. The carcinogenic potency B[a]P equivalent concentration (B[a] Peq) at the three power plants ranged from 3.61 to 25.25 indicating a high carcinogenic burden. The highest (B[a] Peq) was found in samples collected around Matla power station. It can therefore be concluded that the soils were contaminated with PAHs originating from coal-fired power stations.