SERC Scholarly Articles

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Book review : Renewable Energy for Residential Heating and Cooling Policy Handbook
(ICE Publishing, 2012-08) Da Silva, I. P.; Da Silva, Izael
The scope of this book, as far as REHC projects are concerned, covers programme phases: portfolio planning, programme design, implementation and evaluation. It also covers market maturity stages from initial deployment to full market. It considers instruments such as: economic incentives, regulations, information and market activities. As the title mentions, the content is applicable to the residential sector only: new and existing buildings, including single and multi-family dwellings. As far as technology is concerned, it covers active solar thermal systems for air and water heating; biomass (pellets, wood and wood waste); geothermal (ground source and heat-pump) and finally heat-pump technologies based on ambient air heat (air-to-air and air-to-liquid)
Comparative performane analysis of a solar box cooker and improved charcoal stoves in Mozambique
(International Solar Energy Society, 2014-09) Da Silva, I. P.; Cuamba, B. C; Nhabetse, M. T.; Da Silva, Izael
With exception of South Africa, where only 16% of the population depends on traditional biomass energy, almost 80% of the population in the sub-Saharan Africa depends on biomass resources for cooking and heating. The burning of traditional biomass in the so-called three stones stove puts pressure on biomass resources because of its inefficiency. Besides, fumes and soot are related to respiratory diseases that are the common cause for deaths among women and children in Africa. The shortage of fire wood makes women and girls to walk in search of fuel for cooking. Solar cooking is one of the possible solutions for this poignant problem. Yet another partial solution is the use of improved biomass stoves. This paper presents a comparative analysis of the performance of solar box cooker and improved charcoal stove in Mozambique, in its technical and economic aspects.
Economics of a Gasification Based Mini Grid - a case study of a 10 kW Unit in Uganda
(2007-01) Da Silva, I. P.; Buchholz, T.; Volk, T; Tennigkeit, T; Da Silva, Izael
Small-scale wood gasification systems have the potential to contribute to the rural electrification in Uganda. This paper presents an economic analysis of a 10 kW gasifier unit and its minigrid installed on a Ugandan farm. The bioenergy system has been running stable on a six hour daily base for seven months. When the gasifier is operated close to the rated capacity, the gasifier system is economically attractive compared to diesel generated electricity Results indicate that replicating successful wood gasification systems stipulates integration of sustainable fuelwood supply and viable business models.
Electricity from wood-fired gasification in Uganda - a 250 and 10kW case study
(IEEE, 2016-06) Buchholz, T.; Da Silva, I. P.; Furtado, J.; Da Silva, Izael
Wood gasification systems have the potential to contribute to the rural electrification in Sub-Saharan Africa. This paper presents an operational and economic analysis of two wood-based gasification systems (250 and 10 kW) installed in Uganda in 2007. Both systems proved their potential to compete economically with diesel generated electricity when operating close to the rated capacity. At an output of 150 kW running for ~12 h/day and 8 kW running for ~8h/day, the systems produced electricity at US$ 0.18 and 0.34/kWh, respectively. A stable electricity demand close to the rated capacity proved to be a challenge for both systems. Fuelwood costs accounted for ~US$0.03/kWh for both systems. Recovery of even a small fraction of the excess heat (22%) already resulted in substantial profitability gains for the 250 kW system. Results indicate that replicating successful wood gasification systems stipulates integration of sustainable fuelwood supply and viable business models.
Energy efficient building envelope designs for institutional buildings in East Africa
(Domestic use of energy conference, ) Da Silva, Izael; Da Silva, I. P.; Ssekulima , E. B.
To date, insufficient attention has been afforded to the design and energy performance of Institutional buildings in East Africa. As a result, most Institutional buildings in the region do not incorporate the issue of energy efficiency at the design, construction and utilization stages. Institutions are amongst the major consumers of energy in any country most of which is utilized within buildings, thus a thorough critique of the building envelope is necessary to reduce energy wastage within them. The aim of this paper is to present findings of the comparative study carried out on Institutional buildings at Strathmore University Nairobi, Kenya and Makerere University-Kampala, Uganda. The study mainly considered the effect of building envelope designs and orientation to the energy consumption of the buildings. ECOTECT, a Building energy performance analysis tool was employed to quantify the effect of both the conventional and Energy Efficient Building Envelopes to the overall energy consumption of the buildings. The research findings show that the overall energy consumption of Institutional buildings could easily be reduced by about 40% through the design of envelopes suited to the micro-climate of the particular site, proper selection of construction materials vis-a-vis their thermal performance, extensive use of daylighting, wise utilization of water and good building waste management systems as well as utilization of Energy Efficient Appliances within the building. The study also revealed that integration of a Building Management System would significantly reduce resource utilization within the building.
Implementation of triple helix clusters procedure in the Sub-Sahara Africa energy sector
(Universitätsbibliothek Fasanenstr, ) Da Silva, Izael; Da Silva, I. P.; Wassler, S.
Penetration of decentralized power supply for households and commercial enterprises is low in Sub-Sahara Africa. Solar Home Systems (SHS), despite their widespread use in other continents have failed to attain much success in Africa. One of the reasons is the high rate of failure of existing implementations. Data shows earlier failure rates of 50%.1 This is largely attributed to poor quality of products used, inefficient installation, mismanagement and lack of maintenance. To address this problem, the Centre for Research in Energy and Energy Conservation (CREEC) is setting up a Solar PV test laboratory in Uganda. This paper describes the installation process and how to sustain the laboratory after implementation. The lab is intended to provide a forum for training, research and consultancy under CREEC. It is intended as a tool to implement the triple helix and clusters procedure in the PV industry in particular and the energy sector in a more general scope. This paper offers details covering the current situation of the energy sector in Uganda and how the lab supports capacity building in the university to support the upcoming demand.
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).
Innovative Energy Access for Remote Areas “The LUAV-Light up a Village” Project
(Springer Link, 2015-03-04) Da Silva, I. P.; Da Silva, Izael
The Light-up a village (LUAV) program is a rural development initiative designed to improve access to modern energy solutions in remote areas of developing countries. The initiative addresses the challenge of Pico PV market penetration by empowering rural communities to actively participate in lighting up their own villages using micro-solar systems. The LUAV business model was designed by an energy company, Barefoot Power (BFP), which began the LUAV field in 2012 in Uganda. The program incorporates local SACCOs and Community Based Organizations (CBO) as well as local governmental bodies in the identification and recruitment of participants. A LUAV program is designed to involve at least 100 households per community by providing each home with its own power generation solar system to run lighting and mobile device charging services. The participating households are given the option to either pay for the micro solar power system upfront or to pay for it in 3–12 monthly installments. For this pilot program, BFP sourced for funding from private investors to operate a revolving fund which is managed the SACCOs and CBOs who have the mandate to manage debt recovery and keep the revolving fund active. Through this business model, 18 LUAV projects were implemented in Uganda during the 18 month trial period providing lighting and mobile charging services to 3,000 plus households. The program’s success has a growing interest and plans are underway to replicate it in South Sudan, Rwanda and Kenya in 2014. According to the latest count more than 7,000 households have adopted the micro-system through LUAV.
Investigation of solar water heating systems for industrial applications in Northern Ethiopia
(2011-01) Da Silva, I. P.; Kahsay, M. B; Cherkos, R.; Da Silva, Izael
Low temperature water heating for industrial process is one of the ideal applications for solar energy. The paper looks at an investigation of the feasibility of solar water heating systems for industrial applications in Northern Ethiopia. The study was conducted at four factories, namely, a tannery, a particleboard factory, a textile factory and an edible oil factory. The factories use hot water for different processes for the production of their products. The daily hot water consumption is high but most of the processes in the factories require low temperature hot water
Models for conductor size selection in single wire earth return distribution networks
Geofrey B.; Mohammad R. H.; Mikael, A.; Da Silva, I. P.; Da Silva, Izael
The use of the ground as the current return path often presents planning and operational challenges in power distribution networks. This study presents optimization-based models for the optimal selection of conductor sizes in Single Wire Earth Return (SWER) power distribution networks. By using mixed integer non-linear programming (MINLP), models are developed for both branch-wise and primary-lateral feeder selections from a discrete set of overhead conductor sizes. The models are based on a mathematical formulation of the SWER line, where the objective function is to minimize fixed and variable costs subject to constraints specific to SWER power flow. Load growth over different time periods is considered. The practical application is tested using a case study extracted from an existing SWER distribution line in Namibia. The results were consistent for different network operating scenarios.
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)
Planning algorithm for single wire earth return distribution networks
(2012-07) Da Silva, I. P.; Amelin, M.; Hesamzadeh, M. R.; Bakkabulindi,G.
Power flow in earth return distribution systems typically depends on geographical location and specific earth properties. The planning of such systems has to take into account different operational and safety constraints from conventional distribution systems. This work presents the mathematical modeling and planning of Single Wire Earth Return (SWER) power distribution networks. The SWER load flow is modeled and formulated as an optimization problem. Then by using a heuristic iterative procedure, a planning algorithm is developed for the SWER system. The developed procedure includes optimal feeder routing and overhead conductor selection for both primary and lateral feeders with load growth over several time periods. A 30 node test network extracted from a rural area in Uganda is used to test the algorithm's practical application to give reasonable and consistent results. The model presented can be used in planning SWER networks for areas which have previously not been electrified as well as determining suitable upgrades for existing SWER distribution feeders. The algorithm's mathematical modeling and simulations were done using the General Algebraic Modeling System (GAMS)
Power from wood gasifiers in Uganda: a 250 kW and 10 kW case study
(Institution of Civil Engineers (ICE - Energy), ) Da Silva, Izael; Buchholz, T.; Da Silva, I. P.; Furtado, J.
Wood gasification systems have the potential to contribute to the rural electrification in Sub-Saharan Africa. This paper presents an operational and economic analysis of two wood-based gasification systems (250 and 10 kW) installed in Uganda in 2007. Both systems proved their potential to compete economically with diesel generated electricity when operating close to the rated capacity. At an output of 150 kW running for ~12 h/day and 8 kW running for ~8h/day, the systems produced electricity at US$ 0.18 and 0.34/kWh, respectively. A stable electricity demand close to the rated capacity proved to be a challenge for both systems. Fuelwood costs accounted for ~US$0.03/kWh for both systems. Recovery of even a small fraction of the excess heat (22%) already resulted in substantial profitability gains for the 250 kW system. Results indicate that replicating successful wood gasification systems stipulates integration of sustainable fuelwood supply and viable business models.
Reducing Carbon Emissions in a Third Level Educational Institution in Sub-Sahara Africa
(Springer International Publishing Switzerland, 2015) Da Silva, I. P.; Ronoh, G.; Ouma, C.; Jerono, C.; Da Silva, Izael
The effort to reduce carbon emissions as the arguably most prevalent cause of global warming has been a positive trend in most African countries. One of the most successful strategies towards reaching that goal is the shift from fossil fuel power generation to renewable sources of energy such as wind, hydro, geothermal and solar. As Kenya sits on the equator it enjoys an all year round insolation between 5 and 6 kW/m2/day which is more than double of the average insulation in Germany, a country where solar energy is widely used. Taking advantage of a green line of financial support created by the French Government, Strathmore University embarked in a project to install a 600 kW roof-top, grid connected solar PV system to cater for its electricity needs. Having as a background of the newly instituted Feed-in-Tariff regulation, the system is designed to produce more than the required self-consumption such that the extra power can be sold to the utility via a PPA (power purchase agreement) and the revenue used to pay for the electricity used by the university at night. This paper describes the whole process from the technical, regulatory, educational and financial aspect highlighting the positive and negative events along the path such that it can be useful for other private sector institutions interested in greening their sources of energy, invest in renewable energy and thus reduce their operation costs. The authors have written this work having in mind not only countries in Africa but all other countries which sit in the so called “solar belt”.
Rural electrification practicalities of using single wire earth return for low cost grid extension - the case of Ntenjeru Uganda
(International Conference on Energy and Sustainability, 2009-08) Bakkabulindi, G.; Da Silva, I. P.; Lugujjo, E.; Da Silva, Izael
The fact that the vast majority of Uganda’s rural areas remain un-electrified makes it imperative that low cost distribution technologies be implemented in order to provide affordable electricity to rural households. Such low cost technologies include the Shield Wire System (SWS), Single Wire Earth Return (SWER) and appropriate engineering techniques. The SWER technology is presented in this paper as well as the implications of its proposed implementation for electrification of the village of Ntenjeru in Uganda. While SWER can reduce the costs of electrification by more than a third compared to conventional high tension transmission lines, there are stringent grounding and safety issues as well as load capacity constraints involved. Furthermore, with the earth used as a current return path, soil resistivity analysis is important in these systems. Since soil resistivity can vary sharply over varying terrain and in different weather conditions, robust SWER systems have to be carefully designed. An analysis of the financial and electrical load implications of this technology in Uganda’s local conditions will be presented and its viability as a sustainable method for electric energy distribution in the chosen case study area.
Sustainability of Sugarcane, Bagasse, Briquettes and Charcoal Value Chains in Kenya: Results and Recommendations from Implementation of the Global Bioenergy Partnership Indicators
(United Nations Environment Programme, 2019) Williamson, L.; N’Goran, K.; Labriet, M.; Diaz-Chavez, R.; Wanjiru, H.; Ogeya, M.; López, N. G.; Oduor, N.; Ogutu, P. C.; Da Silva, I. P.; Wambugu, A. C.; Ndufa, J.; Ochieng, P. A.; Gitau, J. K.; Muchiri, M.; Nyambati, R.; United Nations Environment Programme; Da Silva, Izael
The following report, Sustainability of Sugarcane Bagasse Briquettes and Charcoal Value Chains in Kenya: Results and Recommendations from Implementation of the Global Bioenergy Partnership (GBEP) Indicators, assesses the current and future potential of Kenya’s bioenergy sector. It outlines the consequences of the widening gap between supply and demand for wood fuel, with the current supply not matching demand in various parts of the country.The report also illustrates key factors that can shape the long-term and periodic monitoring of the sector. Kenya Vision 2030 has identified energy as one of the enablers of the three pillars of its vision. The level and intensity of commercial energy use will be the key indicator of economic growth and development. Bioenergy, like other energy sources, will continue to play a role in both the traditional and commercial energy mix. Kenya’s Nationally Determined Contribution (NDC) includes four key climate change mitigation targets related to forestry and bioenergy: working towards 10 per cent tree cover of the land area of Kenya; promoting clean energy technologies to reduce overreliance on wood fuel; employing low-carbon and efficient transport systems; and using climate-smart agriculture (CSA) in line with the National CSA Framework.
Triple Helix as a strategic tool to fast-track climate change adaptation in rural Kenya - case study of Marsabit County
(Springer, 2021) Da Silva, I. P.; Bricca, D; Micangeli, A; Davide, F.; Cherubini, P.; Da Silva, Izael
The lack of affordable, clean, and reliable energy in Africa’s rural areas forces people to resort to poor quality energy source, which is detrimental to the people’s health and prevents the economic development of communities. Moreover, access to safe water and food security are concerns closely linked to health issues and children malnourishment. Recent climate change due to global warming has worsened the already critical situation. Electricity is well known to be an enabler of development as it allows the use of modern devices thus enabling the development of not only income-generating activities but also water pumping and food processing and conservation that can promote socioeconomic growth. However, all of this is difficult to achieve due to the lack of investors, local skills, awareness by the community, and often also government regulations. All the above mentioned barriers to the uptake of electricity in rural Kenya could be solved by the coordinated effort of government, private sector, and academia, also referred to as Triple Helix, in which each entity may partially take the other’s role. This chapter discretizes the above and shows how a specific county (Marsabit) has benefited from this triple intervention. Existing government policies and actions and programs led by nongovernmental organizations (NGOs) and international agencies are reviewed, highlighting the current interconnection and gaps in promoting integrated actions toward climate change adaptation and energy access.
Using renewable energy in a sustainable and holistic manner as a tool to eradicate rural poverty in Africa
Da Silva, Izael; Da Silva, I. P.; Vendeirinho, V.; Njuguna, P. M; Njogu, M.
Rural poverty in developing countries is a social problem that is well recognized and causes concern globally. The UN recently met to review the MDG's and acknowledge that there was limited progress to date; a looming target date have highlighted the difficulty in addressing development issues on the ground where people are trying to survive, often on as little as $2 per day or less. This paper demonstrates the model of rural village energy services centres by using solar energy to provide solution to most of the problems of a typical African rural village. This stand alone system provides energy services solution leveraging sustainable resources in a holistic, community-integrated fashion to improve health, information, communication, education and preserving the environment while it kick-starts micro-economies in rural villages. It intends to increase productivity and ultimately eradicate poverty. This solution is still in a prototype stage but has its special interest because it hopes to provide clean water and biogas apart from the solar generated electricity. Through the implementation of community energy services, stand alone decentralised solutions intend to divert rural current expenditure on kerosene, offering significant reductions in carbon emissions, environmental damage and respiratory-illness related deaths which were recently estimated at 1.6M per annum worldwide as per a World Bank report. This corresponding increase in energy efficiency drives an increase in productivity and thus a step closer to the realization of the MDGs as has been documented in various case studies (Annual Report 2008 (. (2008). Renewable Energy Services for Developing Countries - In Support of the Millennium Development Goals) [8]. This paper covers the technology implementation starting from demand until it reaches the level of success which then makes it suitable for replication.

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