Estimating wind power generation capacity in Zimbabwe using vertical wind profile extrapolation techniques: A case study

Only 40% of Zimbabwe’s population has access to electricity. The greater proportion of the power is generated from thermal stations, with some from hydro and solar energy sources. However, there is little investment in the use of wind for electricity generation except for small installations in the Eastern Highlands, as Zimbabwe generally has wind speeds which are too low to be utilised for electricity generation. This paper presents the use of vertical wind profile extrapolation methods to determine the potential of generating electricity from wind at different hub heights in Zimbabwe, using the Hellman and exponential laws to estimate wind speeds. The estimated wind speeds are used to determine the potential of generating electricity from wind. Mangwe district in Matabeleland South province of Zimbabwe was used as a test site. Online weather datasets were used to estimate the wind speeds. The investigation shows that a 2.5kW wind turbine installation in Mangwe can generate more than 3MWh of energy per annum at hub heights above 40m, which is enough to supply power to a typical Zimbabwean rural village. This result will encourage investment in the use of wind to generate electricity in Zimbabwe. Highlights Wind power utilisation is low in Zimbabwe. Vertical wind profile is estimated using extrapolation methods. Online weather data for soil and water analysis tool was used. Electricity can viably be generated from wind in Zimbabwe

Systems dynamics modelling to assess the sustainability of renewable energy technologies in developing countries

The'water-energy nexus' is now receiving more attention as policy- and decision-makers grapple with measures to enable the transition to a sustainable, low-carbon economy. South Africa, in particular, finds itself in a polycrisis in terms of dealing with economic development, to alleviate poverty, within water and energy constraints. In the Western Cape Province of the country, desalination is suggested as one solution to the water shortage crisis, but the critical issue is that of energy supply, and the related cost implications, for water supply; concentrated solar thermal technology options are currently considered. In this paper a systems dynamics approach is used to assess the sustainability of these types of renewable energy technologies. The objectives of the paper are thus twofold. Firstly, the paper demonstrates the potential suitability of system dynamics modelling to inform policy- and decision-making in the developing country context. Secondly, the paper highlights the sustainability issues that must be addressed appropriately if concentrated solar thermal, and other renewable energy systems, are to be used in developing countries at the scale of desalination. Recommendations are made accordingly to improve the analysis, and its usefulness, to utilise this technique effectively in the future. © 2011 WIT Press.Conference Pape

An analysis of the effects of clouds in high-resolution forecasting of surface short-wave radiation in South Africa

This is the final version. Available from the American Meteorological Society via the DOI in this record. Data availability statement. All data created or used in this study are available upon request to the South African Weather Service.We assess site-specific surface shortwave radiation forecasts from two high-resolution configurations of the South African Weather Service numerical weather prediction model, at 4 and 1.5 km. The models exhibit good skill overall in forecasting surface shortwave radiation, with zero median error for all radiation components. This information is relevant to support a growing renewable energy sector in South Africa, particularly for photovoltaics. Further model performance analysis has shown an imbalance between cloud and solar radiation forecasting errors. In addition, cloud overprediction does not necessarily equate to underestimating solar radiation. Overcast cloud regimes are predicted too often with an associated positive mean radiation bias, whereas the relative abundance of partly cloudy regimes is underpredicted by the models with mixed radiation biases. Challenges highlighted by the misrepresentation of partly cloudy regimes in solar radiation error attribution may be used to inform improvements to the numerical core, namely, the cloud and radiation schemes. Significance Statement This paper provides the first comprehensive assessment of high-resolution site-specific NWP forecasts of surface shortwave radiation in South Africa, exploring clouds as the main drivers of prediction biases. Error attribution analyses of this kind are close to none for this part of the world. Our study contributes to understanding how cloud and radiation schemes perform over South Africa, representing a step forward in the state of the art. In addition to the scientific interest, the capabilities developed through this work may benefit the second largest economy of the continent. In a country where energy security is of critical relevance, the availability of useful and usable weather information is paramount to support its industry and socioeconomic growth.Met Office Weather and Climate Science for Service Partnership (WCSSP)South African National Research Foundatio

A bibliometric analysis of solar energy forecasting studies in Africa

Solar energy forecasting is considered an essential scientific aspect in supporting efforts to integrate solar energy into power grids. Moreover, solar energy forecasting plays an essential role in mitigating greenhouse gas emissions and conserving energy for future use. This study conducted a bibliometric analysis to assess solar energy forecasting research studies evolution at the continental (Africa) and southern Africa levels. Key aspects of analysis included (i) scientific research trends, (ii) nature of collaboration networks, (iii) co-occurrence of keywords and (iv) emerging themes in solar energy forecasting over the last two decades, between the years 2000–2021. The results indicate that solar energy forecasting research has, on average, expanded by 6.4% and 3.3% in Africa and southern Africa, respectively. Based on the study context, solar energy forecasting research only gained momentum in 2015, peaking in 2019, but it is generally still subtle. The scientific mapping illustrated that only South Africa ranks among the leading countries that have produced high numbers of published documents and also leads in contributions to the research area in both Africa and southern Africa. Three emerging topics were identified from the thematic map analysis— namely, “solar irradiance”, “artificial intelligence” and “clear sky”, which implies that researchers are paying attention to solar irradiance, using modelling techniques that incorporate machine learning techniques. Overall, this study contributes to scientific information on the potential bankability of renewable energy projects that could assist power utilities, governments and policymakers in Africa to enforce the green economy through accelerated decarbonisation of the energy systems and building relationships with developed countries for support and better transitioning to solar energy. From a Water–Energy–Food nexus perspective, the results of this work could assist the scientific community in Africa to take advantage of the inherent interconnectedness of water, energy and food resources, whilst also advancing the use of integrated solutions to shape the focus of solar energy research into a more systems thinking and transdisciplinary approach involving the interconnected primary resources and stakeholders pursuit of the Sustainable Development Goals

A review of fuzzy-based residential grid-connected microgrid energy management strategies for grid power profile smoothing

This book covers different aspects of energy sustainability in residential buildings and neighborhoods, starting from the construction and design aspects, and moving on to HVAC systems and lighting, and the applications, harvesting, use and storage of renewable energy. The volume focuses on smart and sustainable use of energy, discussing both the technological advancements and the economic, social and environmental impacts. Novel approaches to recycling of waste and materials in the context of residential buildings are also presented. This volume will be of interest to researchers and policy makers working in the fields of renewable energy, sustainable design and city planning.Peer ReviewedPostprint (published version