Offsetting particulate matter emissions has become a critical global aim as there are concerted efforts to deal with environmental and energy poverty challenges. This study consists of investigations of computing emissions of particulate matter from biomass fuels in various atmospheres and temperatures. The laboratory setup included a fixed bed electric reactor and a particulate matter (PM) measuring machine interfaced with the flue gas from the fixed bed reactor combustion chamber. The experiments were conducted at seven different temperatures (600°C–1200°C) and six incremental oxygen concentrations (21%–100%). Five biomass types were studied; A-cornstalk, B-wood, C-wheat straw, D-Rice husk, E-Peanut shell, each pulverized to a size of approximately 75 microns. The study shows that PM emitted during char combustion is consistently higher than that emitted during the de-volatilization. During de-volatilization, increase in temperature leads to linear decrease in PM emission between atmospheres of 21%O2 to 50%O2, thereafter, between 70%O2 to 100%O2; increase in temperature leads to a rise in PM emission. The average PM formation from all the five considered biomass is relatively comparable however, with differing atmospheres and temperatures, the fibrous and low-density biomass forms more PM. During char combustion, the study shows that at oxygen levels of 21%, 70%, 90% and 100%, increase in temperature leads to increased PM emission. The increase in oxygen concentration and temperature increases the rate of combustion hence diminishing the time of combustion.

Access to energy is among the key pillars to socioeconomic and improved life style. The East African Community (EAC) countries, also members of sub-Saharan Africa, are among countries with enough energy resources but still struggling with low electricity access, and the lower proportion of citizens with electricity access challenges such as expensive tariff, frequent blackouts, and unreliable service still persists. Diesel technology is among the easy and fast installation technologies for a location with an urgent need of electricity while solar is a clean technology with free fuel. Considering the diversity of electricity tariffs, cost of diesel fuel, and suitability to solar energy exploitation in EAC, this paper intends to provide a technoeconomic analysis for reliable, affordable, and sustainable energy system in the region. A daily load of 94.44 kWh recorded from averaging electricity bills of a luxury house in Kigali, Rwanda, is used as research object, and HOMER simulations are carried on considering the level of such daily load being supplied by either (a) diesel generator, (b) solar+diesel technology, (c) PV+battery storage, or (d) PV+battery storage+grid system in each member country of the EAC. The results show that (a) solar energy is a feasible and applicable technology for energy generation for the whole six EAC countries; (b) for South Sudan, if it is a standalone system, the diesel technology is less costly than solar technology; however, solar energy can still be recommended to be adopted as it has no gas emissions; (c) except South Sudan, PV+battery storage technology is found to be more affordable and cleaner than any technology including diesel; and (d) the option of connecting PV+battery storage to the grid is found more economical for locations where grid interaction is possible because their levelized electricity costs (LCOE) are lower than the real electricity tariffs currently in use within each of the six EAC countries. The solar energy system with battery storage (both off-grid and grid connected) proposed in this research can lead to an efficient increase of national energy resource exploitation in the EAC countries, resulting in reliable, affordable, and sustainable energy access to all the citizenry of the EAC.

Solar PV research in East Africa has concentrated on solar home systems (SHS) in each country. However, several other fundamental advances in the solar photovoltaic (PV) industry have emerged, and the developments have seen the sector experienced significant growth and diversification of models, regulation, and financing. This paper begins with an extensive narrative on the solar PV outlook of each of the six countries studied. A solar PV minigrid was also simulated using HOMER software with a critical load of 2800.0 kWh/day in order to analyze the peak shaving capability and assess the affordability of the solar PV microgrid having commercial and industrial loads. The regional overview of the efforts was identified, followed by a description of the models, payment methods, and barriers encountered collectively. The lessons from this research suggest that there is a vast potential for solar PV micro and minigrid deployment in the region with a population of over 100 million people lacking access to electricity by the end of 2019. It shows that solar PV minigrid deployment in East Africa is still at a nascent phase. Also, minigrid developers face several challenges operating in rural areas. While solar PV minigrids remain fairly nascent in the East Africa region, the technology is gaining traction, a development that indicates budding confidence in the solar PV minigrid technology. This study identifies that (1) with large critical loads (industrial and commercial), solar PV minigrid can still contribute to affordable electricity through peak shaving, except Tanzania; (2) solar PV minigrid projects are largely dependent on donor financing, require vast financial diversity to get off the ground, and offer consistent service; (3) Governments support in the form of National electrification strategies, policies, and regulation are key ingredients for realizing the electrification of rural populations through minigrids; (4) hybrid minigrids and power demand creation have emerged as an approach that ensures sustainability or profitability for the operating solar minigrid firms. Overall, government policy and regulation, funding, and financial sustainability remain the major hurdles to minigrid uptake in the region.

Rwanda is an East African Community (EAC) nation with rapid and remarkable past development in different sectors and still with the ambitious targets and plans to be achieved in the coming years ahead. The government plans universal electricity access by 2024 with 52% grid connection and 48% off-grid connections. In the transport sector, the concept of electric vehicles has been initiated and started in order to contribute to the UN Paris agreement and decrease the reliance of the transport sector on gaseous fuels which are one source of air pollutants leading to climate change, premature deaths, and morbidity associated with poor air quality. With higher electricity demand than the generation of the Rwandan power grid, different energy strategies are being developed with the overall objective to achieve the targeted universal energy access. In order to overcome the aforementioned issue, this paper proposes an integration of solar PV microgrids for the satisfaction of electric vehicle (EV) technology in Rwanda. Using HOMER Grid software, a managed EV charging station is simulated to a grid connected solar PV microgrid with storage in order to assess the economic impact. The results show that the proposed technology can lower the levelized cost (LCOE) of electricity by 139.7%. This study can contribute to further research developments in either different perspectives related to the integration of distributed energy resources (DERs) with electric vehicles or studies related to affordable and environment-energy systems.

Experimental results are presented on the particulate matter emissions from a fixed bed combustion reactor chamber combusting two types of ambient dried biomass fuels, six different particle sizes (0.044-0.149mm) in seven different temperature zones (600-1200 ºC).The fuel was ground into various particle sizes and the temperature of combustion was varied for investigation on the emission due from the various parameters. Measurements were made for particulate matter (PM) during the whole phase of combustion by a portable soot analyzer. The PM investigated here is total catch that includes solid particles of elemental carbon and fuel and condensed organic compounds due from incomplete combustion which are less than or equal to 10µm in aerodynamic diameter. The fuel was ground by a grinder and sieved into different sizes by a shake sieve with various mesh sizes. It was found that the PM emission from both biomass fuels was significantly dependent on the temperature of combustion which in turn dictated the residence time in the combustion chamber. The mean PM mass emissions from wood and peanut shell were established. The optimum combustion temperature was identified to be 900°C attracting PM mitigation of up to 63%. The least PM producing particle size for peanut shell and wood fuel was determined to be 0.149mm combusting at 12000C and 0.074mm combusting at 6000C respectively with capacity to mitigate PM production by a maximum of 30-49%. However the effect of the two parameters was established to be mutually dependent. The time taken for complete combustion reduced steadily with the increase of the temperature from 360 seconds at 600°C to 150 seconds at 1200°C.

Hydroelectricity has long been used in Rwanda. The Ntaruka hydropower plant was constructed during the colonial period in the northern part of Rwanda and it is still in operation. This paper evaluates the annual performance of this power plant and highlights several factors, which are vital for future predictions in the energy generation. Literature search and review coupled with energy generation analysis and forecasting were used for the study. Data were collected through site visits and discussions with the staff of the Rwanda Energy Group. Analysis were made by considering some performance factors of the power plant such as net capacity factor, plant use factor, power factor, voltage profile, frequency profile, general energy profile, and annual energy generation profile taking cognizance of hydropower plant installed capacity. Based on the available monthly operation hours of the power plant and its annual energy generation data between 2011 and 2014, predictions were made using the Statistical Package for Social Sciences (SPPS version 20.0) to forecast future energy generation for the power plant. Results show that the annual energy generation of the power plant varies between 1277 and 4524 MWh, with an average of 2912 MWh within the above years, which is much closer to the average real energy generation obtained between 2011 and 2015 and, therefore, the power plant is in good operating condition. Further research is recommended to consider using staffing levels, plant availability factors, and economic efficiency to determine the economic effectiveness and performance indices of the hydropower plant.

Shade is one of the factors, which affect the characteristics and performance of solar energy systems. It can be classified either as soft or hard shade. Literature search and review were carried out, coupled with MATLAB simulation and experimentation to compare effects of shade on photovoltaic (PV) modules output power. Simulation results showed that the global maximum power points were 34.772%, 32.92%, 26.905% lower than the expected maximum power, respectively for monocrystalline, polycrystalline and amorphous PV modules. Conversely, experimental results showed that 98.2%, 97.72% and 82.2% of output power were lost respectively, for monocrystalline, polycrystalline and amorphous PV modules, when all the modules had no shade and when each module's half-area, was physically shaded by a cardboard. Conclusively, amorphous photovoltaic modules, which showed less sensitivity to both soft and hard shading cases, is recommended for use in situations where shade effects cannot be completely avoided.