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Da Silva, Izael

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Now showing 1 - 10 of 47
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    Publication
    Unlocking climate finance potential and policy barriers—A case of renewable energy and energy efficiency in Sub-Saharan Africa
    (Elsevier B.V, 2022-03) Izael Da Silva, S. Wagura Ndiritu, Edward M. Mungai; Da Silva, Izael
    Sub-Saharan African is in a unique position to reap the socio-economic and environmental benefits of renewable resources, and the energy efficiency practices as the demand for energy in the continent grows. Assessment of the financing potential and the related obstacles for the financing deployment of renewable energy and energy efficiency sectors mapping will be a step forward to help in mobilizing the financial flows into sectors. With the Sub-Saharan Africa population growth, urbanization, economic growth coupled with the global commitment of Sustainable Energy for All Initiative, the need for accessible clean energy has never been more urgent. This paper aims to assess the renewable energy (RE) and energy-efficient (E.E.) investment potential as well as policy barriers in Sub-Saharan Africa (SSA). Analyzing five investment indicators, using secondary sources of information, and conducting interviews with key stakeholders. The RE and E.E. investment potential, investment gap, and policy barriers in 14 countries from West, Central, Southern, and East Africa was quantified conducted. The result of the study indicates a promising yet very susceptible future for the implementation of RE and E.E. in SSA. To enhance access to electricity, promote energy security, and propel economic growth in an environmentally friendly approach, SSA has to overcome the significant challenge of inadequate private and public funding for the energy sector. The conclusion is that there is a need to address the institutional knowledge gaps and policy gaps that will be key to helping in unlocking the financing potential of RE and E.E. in the continent of Africa
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    Technical, Economic and Sustainability Considerations of a Solar PV Mini Grid as a Tool for Rural Electrification in Uganda
    Izael Da Silva; Geofrey Bakkabulindi; Al-Mas Sendegeya; Eriabu Lugujjo; Da Silva, Izael
    The challenges facing rural electrification in Uganda are diverse with less than 3% of the rural population having access to electricity. The establishment of mini-grids powered by renewable energy sources makes it possible to electrify remote areas at affordable rates. In this study, an assessment of a solar PV mini-grid system to provide electricity to forty households in rural Uganda was carried out. The considered system comprised six solar modules each rated 175 Wp, a controller, off-grid inverter and batteries with a capacity of 600 Ah. Manufactured by SMA, the Sunny Island inverter proposed for the mini-grid would ensure provision of grid-quality electricity. The study aimed to investigate the mini-grid’s technical design with focus on optimal distribution against constraints of voltage drops, electrical losses and increasing load. Customised load limiters shared between households using thermistors were included to reduce costs and limit consumption. The incomes of rural households are often seasonal and thus issues pertaining to affordability and sustainability were also considered. Results of the economic analysis showed a payback period of less than 5 years given an affordable fixed monthly tariff for the case study area.
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    Standalone small level power systems based on utilization of agricultural residue (Benecke System)
    (Domestic use of energy conference, ) Da Silva, Izael; Da Silva, Izael Pereira; Krishnan, C. Kutty; Baker , Samuel Kucel; Nturanabo, Francis
    Stand alone small level power systems as a route to low investment decentralized systems with low gestation period is a worthwhile proposition which is being considered and implemented in many third world countries. When the concept of mini-grid is associated with renewable sources of energy such as solar, wind, hydro and biomass, small-decentralized power generation systems lessen the often over-dependence on fossil fuels. Fossil fuel are used at excessively and lead to warming problem due to net carbon-dioxide transfer into the atmosphere besides being a cause of unhealthy trade balance for developing countries. This paper describes a stand alone 0.5 MVA steam powered generator system, which utilizes agricultural residues as fuel. A complete technical description of the system is given. The economic and social impact of such a set-up is also given.
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    On Site Calibration of Inductive Voltage Transformers
    (WSEAS, 2009) Da Silva, I. P.; Demetri, I.; De Silos, A. C.; Brandao, F. A (Jr); Da Silva, Izael
    The accuracy class of an IVT – Inductive Voltage Transformer – is typically assessed in laboratory installations either by comparing with another IVT presenting greater accuracy and traceable to a national laboratory or by using a capacitive divider. Calibration in the field is considered herein, using results obtained from typical open and short circuit tests and winding resistances, performed with common meters. A Möllinger & Gewecke graphic diagram is employed together with the results of an accuracy test previously carried out to determine the exact value of the winding turn relation and of the primary winding dispersion reactance. These values are used to calculate the phase and ratio errors, which must lie between definite limits, defined by the accuracy class of the instrument. Four commercial IVTs were tested to determine the validity of the procedure. The errors are compared with those obtained with the Schering-Alberti method (AC Bridge and comparison with standard IVT)
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    Inductive Voltage Transformers Calibration by the Parameters
    (WSEAS, 2010) Brandao, F.A; Da Silva, I. P.; Demetri, I.; De Silos, A. C.; Diaz, E. M; Da Silva, Izael
    The accuracy class of an IVT - Inductive Voltage Transformer - is typically assessed in laboratory installations either by comparing with another IVT presenting greater accuracy and traceable to a national laboratory or by using a capacitive divider. Calibration in the field using internal parameters is considered herein, using results obtained from typical open and short circuit tests and winding resistances, performed with common meters. A Möllinger & Gewecke graphic diagram is employed together with the results of an accuracy test previously carried out to determine the exact value of the winding turn relation and of the primary winding dispersion reactance. These values are used to calculate the phase and ratio errors, which must lie between definite limits, defined by the accuracy class of the instrument. Four commercial IVTs were tested to determine the validity of the procedure. The errors are compared with those obtained with the Schering-Alberti method (AC Bridge and comparison with standard IVT).
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    Analysis of induction generator controller techniques for Pico hydropower - a case study of a 3kW Pico hydropower scheme in Kasese, Western Uganda
    (2014) Izael Da Silva; Teddy Nalubega; Okou Richard; Mary Suzan Abbo; Da Silva, Izael
    This paper presents a comparative analysis of control techniques used on induction generators for stand-alone Pico hydropower schemes. The techniques were tested on a prototype Pico hydropower system modeled for the site developed in western Uganda by the Centre for Research in Energy and Energy Conservation. The case study scheme to date is manually operated, a process that requires constant attention due to variations in load. This demonstrated the need for an automatic load controller. The site specifications were considered when designing models using Matlab simulink employing the automatic load control techniques. These model designs are simple so that it is affordable for local practical application. The proposed designed control techniques presented in this paper are composed of logic gates, IGBT switch, uncontrolled diode rectifier, the PID controller and other semiconductor devices supplying an electrical load and a ballast load. In addition, the response of the case study site and the Matlab model to load variations is presented.
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    Prospects of the use of solar water heaters in demand side management in Uganda
    Da Silva, Izael; Da Silva, Izael Pereira; Mugisha, Patrick
    The commercial sector in Uganda accounts for about 20% of the total electrical energy consumed in the country, with about 50% consumed in the domestic sector and the remaining 30% to the industrial sector. As the economy continues to grow due to attraction of foreign investment and improvement in local production, more challenges now come up in terms of sustaining the already-attained levels of development and social transformation. It is known that Uganda has only 300 MW of installed electric power capacity. This power is insufficient and could be used better - it is estimated that about 40 MW of the total load is allocated to water heaters. Among the energy-saving schemes being implemented in the commercial sector to avoid or reduce load shedding and to reduce the use of costly generators is the use of Solar Water Heaters (SWHs). A case study on the use of solar water heating in a three-star hotel as a means of implementing an energy saving scheme is presented and an economic analysis of the project is given. Finally, future prospects of use of solar thermal technologies in the commercial sector as a means of energy conservation and as a solution to some of the environmental concerns under Clean Development Mechanisms (CDM) are presented.
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    Use of solar concentrators for steam generation in industrial processes
    Da Silva, Izael; Da Silva, I. P; Okure, M
    Steam plays a substantial role in several industrial processes and is usually required in significant amounts to enable continuous production in beverages, dairies, flower farms, and many other agro-processing industries. Currently, the predominant method for steam generation in such industries is by using furnace oil to fire boilers that generate the required steam. This technique has negative environmental and economical consequences, whose impact is felt especially in developing countries like Uganda. In order to become competitive both locally and internationally, there is need to develop a sustainable technology, which is economically viable, environmentally friendly and provides the steam requirements appropriate for the various industrial applications mentioned above. The solar technology will utilize the considerably high insolation of Uganda which is approximated at 157kWh/m2 per month. This insolation is ten times more than that in London and seven times more than that in Vienna or Berlin. This paper reports on the development of a solar water heater concentrator for use in industries in Uganda. The issues tackled in this work are: different reflective materials, heating fluids, the combination of hybrid flat collector-cumconcentrator, solar tracking possibilities versus static ones, heat power measurement and parabolic design, and economical viability study It is expected that this study, done in cooperation with Solar Construct (U), will create capacity to have this type of solar-powered water heater produced and utilized in Uganda to partially replace furnace oil boilers as a more economical alternative
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    Photovoltaic industry in Uganda : local manufacturers of PV components and imported products - efficiencies and national standards
    (Domestic use of energy conference, ) Da Silva, Izael; Da Silva, I.P; Kyalimpa, E.
    Energy is a key factor for the development of a country. In many remote areas of the third world with good insolation such as Uganda, photovoltaic is one of the most suitable ways of providing energy to rural areas. The government of Uganda is actually pushing what is called “Rural Electrification, Strategy and Plan” to foster a massive purchase and use of Solar Home Systems. Nonetheless, in order to spread photovoltaic technology, one of the main difficulties of a country is the lack of proper framework for importation of the components, maintenance, and data on technical performance of these components. This paper does a national survey on local manufacturers of deep-cycle batteries, charge controllers, lights and inverters; panels are not available as yet and it won’t be in a foreseeable future. Given the importers possibilities, it also does an economic analysis comparing products from China, India, Europe and USA, taking into account the actual governmental position in terms of taxes on photovoltaic products. Some valuable data are presented on the experiences of NGO’s and local communities; how successful have they been, problems they face, etc. The concern about quality and the idea of providing the costumer with a reliable product drove the authors also to analyze the documents of the Uganda National Bureau of Standard establishing national standards and minimal warranty for all components related with solar energy and write some few considerations. Finally, taking advantage of other countries experiences a specific solar home system is designed for Uganda users
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    Benefits of using biogas in households experience from a user in Uganda
    Da Silva, Izael; Sendegeya , Al-Mas; Ssebuwufu , Pancras John; Da Silva, Izael Pereira
    This paper discusses the socio-economic benefits of using biogas based on the experience of a long term user as a typical example. A floating drum type of digester was installed with a capacity of 6.5 m3 in the year 2000 at a total cost of US$ 1,830. The gas generated is used exclusively for cooking. For the user, his typical kitchen day consists of three meals for a household of 8 people. Prior to the installation of the biogas plant, the user was using liquefied petroleum gas (LPG) supplied in 15 kg cylinders at an average cost of US$ 23 per cylinder and used to consume an average of 3 cylinders in 2 months bringing a monthly expenditure on the kitchen fuel of US$ 35 including transport costs for the cylinder. The user has now totally substituted LPG with biogas which translates into an annual average saving of US$ 420. At this rate of saving, the break-even point for the full recovery of the installation costs is about five years. Since installation the digester has not had any significant breakdown, so no major maintenance has been required. The water used for mixing the cow dung into slurry is harvested rainwater. Thus according to his experience it indicates that the use of biogas offers a substantial cost saving on domestic energy. In addition to the economic benefits, other benefits include increased organic agricultural production when the sludge is used as fertiliser. The use of the slurry as bio-fertiliser on his small vegetable farm (about 0.5 ha), has helped him to save money that would have been used to buy the imported artificial fertilisers. Fermenting the cow dung in a biogas digester instead of composting it in open air provides several other advantages, ranging from a foul odour-free environment to improvements in the general health conditions in the home. Thus, a reduction in the unhealthy smell from the compost dumps where the cow dung used to be deposited, as well as a reduction in free methane gas (one of the green house gases, GHG) which used to be emitted direct into the atmosphere by the decomposing dung.