Role of FACTS devices in enhancing integration of renewable energy sources to the grid: a review

2018 Conference paper. Theme (Renewable Energy and Energy Efficiency)The modern power system is facing challenges such as exponential growth in demand, constrained infrastructure and deregulation of electricity markets. For a sustainable energy system, it is necessary to meet energy need by utilizing renewable energy sources (RES), which have minimum environmental impact. Over the last two decades, renewable energy generation and integration into the grid has received a lot of attention worldwide. In 2017 alone, more than half of all new electricity capacity installed globally was from RES. However, RES such as solar photovoltaic and wind energy are intermittent in nature. Integrating variable generating sources into the grid can cause problems such as voltage fluctuations and interruptions, which affect the performance of utility equipment as well as end user. Over the years, flexible AC transmission system (FACTS) device utilization in power systems has been on the rise. FACTS refer to the application of power semi-conductor devices to control electrical variables, thus influencing power flow and enhancing power system security. This paper investigates the role of FACTS devices in expediting renewable energy integration in power systems. Challenges associated with renewable energy injection into the grid, and how FACTS devices can mitigate these issues is presented. We conclude that the penetration rate of renewable energy will be accelerated if FACTS devices are incorporated in RES integration projects.Jomo Kenyatta University of Science and Technology, Kiambu, Keny

A Rapid Assessment of Avoidable Blindness in Southern Zambia

INTRODUCTION: A rapid assessment of avoidable blindness (RAAB) was conducted in Southern Zambia to establish the prevalence and causes of blindness in order to plan effective services and advocate for support for eye care to achieve the goals of VISION 2020: the right to sight. METHODS: Cluster randomisation was used to select villages in the survey area. These were further subdivided into segments. One segment was selected randomly and a survey team moved from house to house examining everyone over the age of 50 years. Each individual received a visual acuity assessment and simple ocular examination. Data was recorded on a standard proforma and entered into an established software programme for analysis. RESULTS: 2.29% of people over the age of 50 were found to be blind (VA <3/60 in the better eye with available correction). The major cause of blindness was cataract (47.2%) with posterior segment disease being the next main cause (18.8%). 113 eyes had received cataract surgery with 30.1% having a poor outcome (VA <6/60) following surgery. Cataract surgical coverage showed that men (72%) received more surgery than women (65%). DISCUSSION: The results from the RAAB survey in Zambia were very similar to the results from a similar survey in Malawi, where the main cause of blindness was cataract but posterior segment disease was also a significant contributor. Blindness in this part of Zambia is mainly avoidable and there is a need for comprehensive eye care services that can address both cataract and posterior segment disease in the population if the aim of VISION 2020 is to be achieved. Services should focus on quality and gender equity of cataract surgery

Grand Challenges in global eye health: a global prioritisation process using Delphi method

Background We undertook a Grand Challenges in Global Eye Health prioritisation exercise to identify the key issues that must be addressed to improve eye health in the context of an ageing population, to eliminate persistent inequities in health-care access, and to mitigate widespread resource limitations. Methods Drawing on methods used in previous Grand Challenges studies, we used a multi-step recruitment strategy to assemble a diverse panel of individuals from a range of disciplines relevant to global eye health from all regions globally to participate in a three-round, online, Delphi-like, prioritisation process to nominate and rank challenges in global eye health. Through this process, we developed both global and regional priority lists. Findings Between Sept 1 and Dec 12, 2019, 470 individuals complete round 1 of the process, of whom 336 completed all three rounds (round 2 between Feb 26 and March 18, 2020, and round 3 between April 2 and April 25, 2020) 156 (46%) of 336 were women, 180 (54%) were men. The proportion of participants who worked in each region ranged from 104 (31%) in sub-Saharan Africa to 21 (6%) in central Europe, eastern Europe, and in central Asia. Of 85 unique challenges identified after round 1, 16 challenges were prioritised at the global level; six focused on detection and treatment of conditions (cataract, refractive error, glaucoma, diabetic retinopathy, services for children and screening for early detection), two focused on addressing shortages in human resource capacity, five on other health service and policy factors (including strengthening policies, integration, health information systems, and budget allocation), and three on improving access to care and promoting equity. Interpretation This list of Grand Challenges serves as a starting point for immediate action by funders to guide investment in research and innovation in eye health. It challenges researchers, clinicians, and policy makers to build collaborations to address specific challenge

Nonfarm Work and Fertilizer Use Among Smallholder Farmers in Kenya: A Cross-Crop Comparison

We use panel data from a sample of smallholder farmers in Kenya to test how the effects of nonfarm earnings on demand for fertilizer vary across different crops, namely: a major food staple (maize), an emerging cash crop (vegetables), and a traditional export crop (tea). We find that, holding other factors constant, nonfarm earnings from either business or salaried work detract from fertilizer application rates on maize and vegetables. While nonfarm salaried earnings appear to have no effect, business income positively affects fertilizer use and application rates on tea. Results suggest competition for household resources between farm and nonfarm sectors among growers of Kenya’s main staple and emerging cash crops, but possible complementarity among tea growers, who farm a traditional perennial export crop with longer planning horizons

Off-farm Work and Fertilizer Intensification among Smallholder Farmers in Kenya: A Cross-Crop Comparison

Off-farm work accounts for a substantial and growing share of household income among smallholder farmers in most of Sub-Saharan Africa, but evidence on the effects of these earnings on farm investments remains sparse. We use panel data from a sample of smallholder farmers in Kenya to estimate input demand for fertilizer, testing the effects of earnings from nonfarm activities, agricultural wage labor on other farms, and combined off-farm sources. We compare effects among three types of crops: a major food staple (maize), and emerging cash crop (vegetables), and a traditional export crop (tea). We find that, holding other factors constant, off-farm work detracts from fertilizer application rates on maize and vegetables. Nonfarm income drives these results. Off-farm work has no effect on fertilizer application to tea. Results suggest competition for household resources between farm and nonfarm sectors, with implications for public investments in rural development as Kenyan smallholders commercialize

Current status of insecticide resistance among malaria vectors in Kenya

Abstract Background Insecticide resistance has emerged as one of the major challenges facing National Malaria Control Programmes in Africa. A well-coordinated national database on insecticide resistance (IRBase) can facilitate the development of effective strategies for managing insecticide resistance and sustaining the effectiveness of chemical-based vector control measures. The aim of this study was to assemble a database on the current status of insecticide resistance among malaria vectors in Kenya. Methods Data was obtained from published literature through PubMed, HINARI and Google Scholar searches and unpublished literature from government reports, research institutions reports and malaria control programme reports. Each data source was assigned a unique identification code and entered into Microsoft Excel 2010 datasheets. Base maps on the distribution of insecticide resistance and resistance mechanisms among malaria vectors in Kenya were generated using ArcGIS Desktop 10.1 (ESRI, Redlands, CA, USA). Results Insecticide resistance status among the major malaria vectors in Kenya was reported in all the four classes of insecticides including pyrethroids, carbamates, organochlorines and organophosphates. Resistance to pyrethroids has been detected in Anopheles gambiae (s.s.), An. arabiensis and An. funestus (s.s.) while resistance to carbamates was limited to An. gambiae (s.s.) and An. arabiensis. Resistance to the organochlorine was reported in An. gambiae (s.s.) and An. funestus (s.s.) while resistance to organophosphates was reported in An. gambiae (s.l.) only. The mechanisms of insecticide resistance among malaria vectors reported include the kdr mutations (L 1014S and L 1014F) and elevated activity in carboxylesterase, glutathione S-transferases (GST) and monooxygenases. The kdr mutations L 1014S and L 1014F were detected in An. gambiae (s.s.) and An. arabiensis populations. Elevated activity of monooxygenases has been detected in both An. arabiensis and An. gambiae (s.s.) populations while the elevated activity of carboxylesterase and GST has been detected only in An. arabiensis populations. Conclusions The geographical maps show the distribution of insecticide resistance and resistance mechanisms among malaria vectors in Kenya. The database generated will provide a guide to intervention policies and programmes in the fight against malaria