- ItemRooftop solar PV potential assessment in the City of Johannesburg(Stellenbosch : Stellenbosch University, 2017-12) Ntsoane, Moroasereme; Brent, Alan C.; Stellenbosch University. Faculty of Economic and Management Sciences. Centre for Renewable and Sustainable Energy Studies.ENGLISH SUMMARY : Cities are the modern era’s undisputed drivers for economic growth and development. But cities are also highly energy and resource intensive. Therefore, it is predictable that cities would be active participants in the global effort to creatively strike a balance between resources consumption and economic growth for a sustainable future. Part of this is exploiting the often neglected, but vital, solar photovoltaic (PV) resource and rooftop real estate within cities. At face value, a city with the real estate infrastructural sophistication of the City of Johannesburg (CoJ), presents an attractive opportunity for generating renewable energy from its building rooftops. However, the magnitude of this potential is yet to be fully characterised. Assessments of the rooftop solar PV potential of buildings in inner city locale are made complex by the variety of building typologies and rooftop accessibility. The main objective of this research was to assess the technical potential of rooftop PV generation in the inner city core of the CoJ, using a rapid, simple, accessible, effective, and computationally light methodology. The sample for the study was the entire population of buildings located in the central business district (CBD) of the CoJ, made up of 202 buildings across a 1.64 km2 area. Digital images of the individual building rooftops were used. The inner city core of the CoJ was found to have a rooftop availability factor of 46% (375 985 m2), 17% (140 995 m2) of which was considered to be available and suitable for system installations. The area could accommodate a system with a technical capacity of 22.6 MW and an average annual production of 38 399 915 kWh, which constitutes a mere 0.23% of the CoJ’s current annual electricity consumption. The full installation of such a system would reduce the CoJ’s electricity services revenue by 0.31%, whilst positively impacting its carbon emissions inventory through the offsetting of 36 096 tCO2e. The outcome of the research shows that the technical potential for rooftop PV installation in the central business district of CoJ, whilst seemingly attractive at face value, was, in reality, insignificant. The immateriality of the determined technical potential – as is reasonable to expect – would be aggravated further by the incorporation of economic and financial constraints, as well as real-time building-to-building shadow analysis. Whilst the research has demonstrated that rooftop PV in the inner city core of the CoJ, and possibly in CBD areas of other cities displaying similar building typology, is limited in scope and impact, the same argument cannot be made about the entirety of the building rooftops in the CoJ. After all, building typology beyond the inner city core boundaries is dominated by less dense, low-rising, residential, industrial and commercial roof space, which possibly holds immense potentials for rooftop PV. This means that the CoJ, in seeking to transform its energy supply options through exploitation of its real estate, should focus attention away from the inner city core for optimised impact.
- ItemAgricultural residue as a renewable energy resource(Stellenbosch : University of Stellenbosch, 2011-03) Potgieter, Johannes George; Van Niekerk, J. L.; De Lange, L.; University of Stellenbosch. Faculty of Engineering. Centre for Renewable and Sustainable Energy StudiesENGLISH ABSTRACT: In the Greater Gariep agricultural area adjacent to the Orange River between Prieska and the Vanderkloof dam alone an estimated 311 000 ton/yr of maize and wheat straw is available. These agricultural residues have an energy equivalent of 196 000 ton of coal per year and should be utilised as a renewable energy resource. A technical and financial evaluation on the collection and transport of agricultural residue showed that the Hopetown area has the highest concentration of agricultural residue in the Greater Gariep agricultural area with approximately 68 000 ton/yr that is spread out over 76 kmª. Briquetting, combustion, pyrolysis and gasification were identified as the technologies with the highest potential to convert agricultural residue into a higher grade energy product in this area. The expected overall energy conversion efficiency for a plant capacity between 5 000 to 100 000 ton/yr is 98.9%, 10-25%, 25-30% and 28-36% for the briquetting, combustion, pyrolysis and gasification plants respectively. A financial evaluation based on the internal rate of return and the net present value of investment showed that the briquetting plant is financially feasible and the most profitable for capacities between 25 000 and 60 000 ton/yr while the pyrolysis plant was financially feasible and the most profitable technology for capacities greater than 60 000 ton/yr. A sensitivity and risk analysis done on the proposed briquetting and pyrolysis plants to evaluate the impact of market fluctuations on the profitability of the power plants exposed the briquetting plant as a very high risk investment, mainly because of the sensitivity to the selling price of fuel briquettes and the high maintenance cost associated with the briquetting equipment. Although the proposed pyrolysis plant is sensitive to variation in the electricity price, the risks associated with the market conditions for the pyrolysis plant is very low and an internal rate of return of 15% is still projected at the minimum expected electricity price. From the study it is clear that the utilisation of agricultural residue available in the Greater Gariep agricultural area is technically and financially viable.
- ItemWater scarcity and electricity generation in South Africa(Stellenbosch : University of Stellenbosch, 2010-12) Wassung, Natalie; University of Stellenbosch. Faculty of Engineering. Centre for Renewable and Sustainable Energy Studies; Stellenbosch University. Faculty of Economic and Management Sciences. Dept. of School of Public Leadership.ENGLISH ABSTRACT: South Africa has a mean annual precipitation far lower than the global average. This is a fundamental constraint to development, especially when the country has already run out of surplus water and dilution capacity. To add further pressure, Southern Africa’s water resources are expected to decrease as a result of climate change. Despite the potential devastation, the country’s response to climate change has been limited. South Africa’s energy sector is dominated by coal power stations and is the country’s primary emitter of carbon dioxide. Given the significantly higher water usage of coal-fired power plants compared to that of most renewable energy power plants, the transition to a clean energy infrastructure might be more successfully motivated by water scarcity than by the promise of reduced carbon emissions. This article analyses more critically the impact of coal-fired electricity generation on South Africa’s water resources, by estimating a water-use figure that extends backwards from the power plant to include water used during extraction of the coal. This figure can then be compared to the water usage of alternative electricity generation options. It is then possible to estimate how much water could be saved by substituting these alternatives in place of additional coal-fired plants.
- ItemAn economic evaluation of a wind power electricity generating farm in South Africa(2011-12) Menzies, Greig Hamilton; Hosking, S. G.; Sale, M. C.; Stellenbosch University. Faculty of Engineering. Centre for Renewable and Sustainable Energy StudiesENGLISH ABSTRACT: Renewable energy technology has received much attention over recent years. The depletion of known fossil fuel reserves and the volatility of international fuel prices require that society looks beyond the current coal-dominated electricity generation methods. Wind energy is an internationally well-established technology with large markets in major countries around the world, such as the USA and Germany. South Africa has the potential to generate large amounts of electricity from the wind because of the strength of the country’s wind resource. The long coast line and open areas are ideal for the exploitation of wind energy.
- ItemA value chain analysis of the solar water heater industry in the Western Cape : investigating opportunities for local economic development, poverty alleviation and energy conservation(Stellenbosch : Stellenbosch University, 2010-12) Du Toit, Hendrik Jacobus; Van Breda, John; Stellenbosch University. Faculty of Economic and Management Sciences. School of Public Leadership.ENGLISH ABSTRACT: Low-income households in the Western Cape primarily use small electrical kettles to heat water for bathing and cleaning. This energy usage pattern is problematic in that; • It is based on unsustainable energy sources that cause environmental degradation, • Electricity is becoming more expensive in South Africa which strains the limited income of poorer households and • The national utility, Eskom, is struggling to meet the demand for electricity. If energy-intensive development paths are followed these problems will escalate further. Solar water heating offers a synergic (Max-Neef 1991), if partial, solution for the situation. By decoupling hot water usage from increased electricity usage, solar water heaters (SWHs) can reduce electricity demand and thus environmental degradation. The large quantities of hot water (relative to electrical kettles) that they provide also fulfil a developmental service by improving quality of life and personal health. The manufacturing and installation of solar water heaters could serve as a further catalyst for development by providing opportunities for economic development. Unfortunately the high capital cost of SWHs remains a barrier to the rollout of the technology in lower income groups. The objective of this thesis is to contribute to the elimination of this barrier through providing insight into; the hot water requirements of low-income households, the potential electricity and carbon emission savings that solar water heaters present, and the cost drivers and job creation potential of the solar water heating value chain. The research hypothesis is that: Solar water heaters (SWHs) are a potential synergic satisfier to achieve sustainable development in low income communities by providing an improved energy service, reducing environmental degradation and creating employment opportunities. The high price of the technology makes intervention in the form of subsidies and/or regulation from the appropriate level(s) of government critical for the realisation of this potential. The methodology used to test the hypothesis is quantitative and qualitative in nature with data obtained through a survey of 90 low-income households in Stellenbosch, a behavioural study of two households wherein solar water heaters were installed and a value chain analysis of the SWH industry in the Western Cape. The key findings of the research include that, SWHs offer a real improvement in quality of life for low-income households and that they reduce electricity consumption relative to a level of development. The key barrier to cost reductions in the solar water heating industry is found to be the small size of the industry which leads to an inability to source material, especially copper, at competitive prices. It is proposed that government sponsored rollout programs could alleviate this barrier, leading to the development of a robust industry. Job creation potential is found to be relatively small but a suggested rollout programme for SWHs in the Western Cape shows that the benefits of the technology can be realised and several thousand jobs created in a fiscally prudent manner. The thesis is focuses on households from LSM categories 5-8 in the Western Cape Province. Stellenbosch Municipality is used as a specific case study area.