SERC Scholarly Articles

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Consumer price sensitivity impact on tariff level in isolated rural power systems
(2006-09) Silva I.P; Sendegeya, A; Amelin,A; Soder, L; Lugujjo, E
Uncertainties in demand and supply are among the challenging aspects when planning isolated power systems as well as one of the reasons why plans are not as optimal as expected. Most consumers in these areas are price sensitive and their sensitivity may change over time. To be able to estimate the outcome of certain investments in such markets with uncertainties, it is important to have a realistic modelling of the market. The modelling of markets can be performed using probability methods. This paper presents a methodology using Monte Carlo simulation to analyze the impact of price sensitivity of consumers on the probability distribution of tariff as a basis for making decision during planning. The stochastic nature of the market due to uncertainties in sensitivity, demand and supply has been modelled explicitly by random variables of given distributions. The developed model has been demonstrated on a small test system. The results include probability distributions showing the impact on the tariff levels for various system configurations.
Electricity production from energy plantations : results from a feasibility and impact scoping study in Northern Uganda for a 50 MWe grid model
(European Biomass Conference, 2007) DaSilva, Izael; Buchholz, Thomas; Tennigkeit, Timm; Timothy A., Volk; Da Silva, Izael
Uganda currently faces an electricity crisis due to high fossil fuel prices and falling levels of lake Victoria affecting hydro power capacities. In this paper, we introduce a feasibility study for a 50 MW biomass fired power plant covering plantation design, conversion technology, environmental and social impacts, anticipated problems, overall economics, project status, and benefits of the project. The 30,000 ha project area consists mainly of Eucalyptus and native Markhamia lutea stands. Results indicate that this project can provide electricity to a competitive price which is considerably lower than generated by fossil fuel powered generators.
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.
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)
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.
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).
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
Modeling the profitability of power production from short-rotation woody crops in Sub-Saharan Africa
(2012) Da Silva, I. P; Da Silva, Izael
Increasing electricity supply in Sub-Saharan Africa is a prerequisite to enable economic development and reduce poverty. Renewable sources such as wood-fueled power plants are being promoted for social, environmental and economic reasons. We analyzed an economic model of a vertically integrated system of short-rotation woody crops (SRWC) plantations coupled with a combined heat and power (CHP) plant under Sub-Saharan African conditions. We analyzed a 5 MW (electric) base-case scenario under Ugandan conditions with a 2870 ha Eucalyptus grandis plantation and a productivity of 12 t ha 1 y 1 (oven dry basis) under a 5-year rotation. Plant construction and maintenance constituted 27% and 41% of total costs, respectively. Plantation productivity, carbon credit sales as well as land, fuel, labor & transport costs played an economic minor role. Highly influential variables included plant efficiency & construction costs, plantation design (spacing and rotation length) and harvest technologies. We conclude that growing 12e24 t ha 1 y 1 at a five-year rotation can produce IRR’s of 16 and 19% over 30-years, respectively. Reducing rotation length significantly reduced short-term financial risk related to frontloaded costs and relatively late revenues from electricity sales. Long-term feed-in tariffs and availability of a heat market played a significant economic role. The base-case scenario’s 30-year IRR dropped from 16% to 9% when a heat market was absent. Results suggest a leveling-off of economies-of-scale effects above 20MW(electric) installations. Implementation-related research needs for pilot activities should focus on SRWC productivity and energy life cycle analysis
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)
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)
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.
Analysis of induction generator controller techniques for Pico hydropower a case study of A 3kW Pico hydropower scheme in Kasese, Western Uganda
(IEEE, 2014) Nalubega, Teddy; Da Silva, Izael Pereira; Okou, Richard; Abbo, Mary S.; 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.
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.
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”.
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.
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.
The impact of the SERC based solar PV outreach training program in Kenya
(Strathmore Energy Research Center, 2016-06-23) Silva, I. P.; Ronoh, G.; Nalubega, T.; Njogu, M.; Da Silva, Izael
In this paper it is described how Strathmore Energy Research Centre developed an outreach project funded by USAID, National Science Foundation (NSF) to empower technical institutions to offer solar courses hence creating a pool of qualified technicians spread throughout the geography of the country. Presently the situation is that Kenya has around 1000 solar technicians working in the market with no formal solar PV training or accreditation. The National Industrial Training Authority NITA, which regulates nonacademic skills or craft based training, was helped by this project to develop a PV solar curriculum at three levels (T1/T2/T3) which empowers from craft level technicians to engineers to deal with design, installation and maintenance of PV systems from solar lantern up to utility size level. ERC, the Energy Regulatory Commission for Kenya has supported the initiative as technicians once trained can be accredited by and thus further strength the industry. By June 2016, which is the end of the program, Kenya is to have 1800 accredited technical personnel near almost every major town in the country. The paper describes the positive and negative aspects of this venture.
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.
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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