Interconnection of solar home systems as a path to bottom-up electrification

Solar Home Systems (SHSs) have revolutionised electricity access for off grid communities, but have a number of significant limitations. They have limited demand diversity, produce excess energy and lack a clear pathway to scale alongside growing energy demand. Electrical interconnection of existing installed SHSs to create minigrids could offer a way to both scale up energy demand and make use of wasted energy. This bottom-up approach has the potential to be flexible to the changing needs of communities, by using SHSs as a starting point for wider electrification, rather than the end goal. Despite this potential, little analytical work has been undertaken to model SHS interconnection, particularly accounting for demand diversity and long-term system performance. This thesis presents a time sequential stochastic model of interconnected SHSs, to investigate these systems under multi-year operational timescales at high temporal resolution. It is shown for case study systems based on real SHS topologies that there exists significant demand diversity, with small clusters of 20 houses with identical appliances exhibiting an average peak demand of less than 70% of the combined worst-case peak for individual SHSs. Excess generated energy is shown to be an average of 100 Wh a day for the smaller system types and 1000Wh a day for larger systems. Interconnection of these systems demonstrates a significant reductions in LCOE for all system types compared to islanded operation, through more optimal dispatch of battery storage assets and use of excess energy. This resulted in a final LCOE of $0.63/kWh for a network of 12 large SHSs - a reduction of 48.12$0.703/kWh for a network of 12 small SHSs - a reduction of 55.23% compared to islanded operation. This informed an investigation of possible operational business models for a network of SHSs, with three approaches proposed - an Energy System Operator with direct control over all users’ systems, an Aggregator model, where the system operator facilitates an energy market and a Peer-to-Peer model with direct consumer to consumer energy trading. This thesis provides a robust evidence base for SHS interconnection – demonstrating that the approach can lower cost of energy and facilitate demand growth for off grid energy consumers and proposes appropriate business models to deliver this affordable and clean energy.Solar Home Systems (SHSs) have revolutionised electricity access for off grid communities, but have a number of significant limitations. They have limited demand diversity, produce excess energy and lack a clear pathway to scale alongside growing energy demand. Electrical interconnection of existing installed SHSs to create minigrids could offer a way to both scale up energy demand and make use of wasted energy. This bottom-up approach has the potential to be flexible to the changing needs of communities, by using SHSs as a starting point for wider electrification, rather than the end goal. Despite this potential, little analytical work has been undertaken to model SHS interconnection, particularly accounting for demand diversity and long-term system performance. This thesis presents a time sequential stochastic model of interconnected SHSs, to investigate these systems under multi-year operational timescales at high temporal resolution. It is shown for case study systems based on real SHS topologies that there exists significant demand diversity, with small clusters of 20 houses with identical appliances exhibiting an average peak demand of less than 70% of the combined worst-case peak for individual SHSs. Excess generated energy is shown to be an average of 100 Wh a day for the smaller system types and 1000Wh a day for larger systems. Interconnection of these systems demonstrates a significant reductions in LCOE for all system types compared to islanded operation, through more optimal dispatch of battery storage assets and use of excess energy. This resulted in a final LCOE of $0.63/kWh for a network of 12 large SHSs - a reduction of 48.12$0.703/kWh for a network of 12 small SHSs - a reduction of 55.23% compared to islanded operation. This informed an investigation of possible operational business models for a network of SHSs, with three approaches proposed - an Energy System Operator with direct control over all users’ systems, an Aggregator model, where the system operator facilitates an energy market and a Peer-to-Peer model with direct consumer to consumer energy trading. This thesis provides a robust evidence base for SHS interconnection – demonstrating that the approach can lower cost of energy and facilitate demand growth for off grid energy consumers and proposes appropriate business models to deliver this affordable and clean energy

You are what you measure! But are we measuring it right? An empiric analysis of energy access metrics based on a multi-tier approach in Bangladesh

Measuring energy access through binary indicators is insufficient, and often, even misleading. In this work, the SE4ALL global tracking framework, and the recently introduced ESMAP multi-tier approach, is critically discussed analyzing questionnaire based primary data from rural Bangladesh. The performance of different energy interventions is evaluated using the new tier framework. The challenges in its application lie in reliable data collection, adequate gradation of indicators, and an effective algorithm for the tier assignment based on the specified set of attributes. The study showcases very high sensitivities to parameter changes, different algorithms, and data requirements. The results reveal a clear trade-off between capturing the multi-dimensionality of energy access and the simplicity of an easy to use global framework. Suggestions to improve the measuring approach are made and conclusions are drawn for possible implications of the tier framework for different energy service offers in the market. Strengths and weaknesses of the present measurement scheme are discussed and country specific results interpreted through targeted gap analysis for future policy advice

Assessing the market for solar photovoltaic (PV) microgrids in Malawi

Access to energy is widely acknowledged as an enabler for development, and a lack of energy is a barrier to economic empowerment. Currently just 12% of the Malawian population have access to the national electricity grid, with rural electrification at only 5.3%. Solar photovoltaic (PV) microgrids offer increased access levels over pico-solar systems and solar-home systems, and are a successful rural electrification method in many areas of Africa. This paper addresses the research question of: "what is the market potential for solar microgrids in Malawi?" through a multidisciplinary methodology and outlines necessary steps to overcome the key risks and barriers for implementation nationally. Case studies of existing initiatives in Kenya and Rwanda have been used to inform a system and business design appropriate to Malawi. The market potential of PV microgrids in Malawi has been identified and quantified through a novel approach combining microgrid optimisation software HOMERPro with Geographic Information Systems tools. The methodology also includes an energy ecosystem mapping exercise to identify and frame influencing parameters affecting microgrid implementation nationally. The findings show that solar microgrids are cost competitive with diesel microgrids in all locations in Malawi, although the addition of dispatchable diesel generation may provide economic benefits in larger, more urban systems. To implement solar microgrids would cost approximately $210 per person and average operational expenses of$17 per person per year. It was determined that 42% of Malawians may be most cost effectively served by existing infrastructure, 37% would be best served by microgrids and 21% would be best served by solar-home systems

Bioenergy and Minigrids for Sustainable Human Development

Human-caused climate change and deep disparities in human development imperil a prosperous and just future for our planet and the people who live on it. Transforming our society to mitigate global warming offers an opportunity to rebuild energy systems to the benefit of those who are harmed by global inequality today. I examine this opportunity through the lens of two sustainable energy technologies: bioenergy and miniature electricity grids (minigrids). Bioenergy requires land to produce biomass and is inextricably connected to the surrounding environment, agricultural livelihoods, and food system. I apply data science tools to study aspects of land use and food security that may intersect with increasing bioenergy production. I assess the potential to use over one billion hectares of grazing land more intensively with an empirical yield gap analysis technique called climate binning. To clarify how agricultural and socioeconomic characteristics relate to national food security, I study the relative importance of several drivers using simple linear regressions with cross validation and random sampling techniques. Minigrids can supply clean, reliable electricity to un- and under-served communities, but small and hard-to-predict customer loads hamper their financial viability. To improve predictions of daily electricity demand of prospective customers, I test a data-driven approach using customer demographic surveys and machine learning models. I also investigate opportunities to grow loads by stimulating income-generating uses of minigrid electricity in twelve Nigerian agricultural value chains. I conclude by emphasizing the fundamental complementarity of energy and agriculture as change levers for human development, especially in rural communities with low energy access and high poverty. I also provide recommendations to support the effective use of energy to solve pressing agricultural problems and drive multiplicative human development benefits

Design of a solar energy centre for providing lighting and income-generating activities for off-grid rural communities in Kenya

One of the biggest challenges in the developing world is the provision of affordable and reliable electricity access to rural and marginalized people where grid extension is prohibitively expensive. Many off-grid schemes to date have focused on household lighting with mixed success. Some of the greatest difficulties have been around affordability and sustainability of the service provided, with systems being abandoned or removed due to broken equipment or inability of the user to continue paying for the service. It has been reported that key to the success of the best programs has been the means to improve the economic prospects of the users. In this paper the design of a solar energy centre for a rural village in Kenya, that enables income-generating activities for the community in addition to basic lighting and mobile phone charging provision, will be reported. We have found that it is possible to use the energy centre model to provide power for activities that could offer a source of income for the community, at an affordable cost with equipment available in Kenya today. It is believed that this will allow the community to develop economically and therefore ensure the sustainability of the off-grid power supply

The Case for DC: Motivation of Modern Topologies, DC-Powered Solutions, and Applications within Residential Environments

The more than a century-old debate between AC and DC has its roots in an electrical distribution challenge, tackled by rival inventors Nikola Tesla and Thomas Edison during the late 1800s. Although originally collaborating on the improvements of Edison’s work, the pair eventually parted ways due to conflicts in their personalities and business pursuits. Edison’s direct current (DC) system leveraged a constant voltage and current to supply electricity, which was initially sufficient for small locales and geographical regions. However, DC encountered a major obstacle when longer-range transmission was required; there was simply no way to easily convert it between higher and lower voltages. These step-up and step-down conversions were critical for transmission, as power line losses are reduced significantly when proportionally increasing voltage levels. Tesla’s alternating current (AC), on the other hand, was readily compatible with the newly christened transformer, a device which possessed the ability to effectively adjust AC voltages on demand. With more and more entities investing into the AC-based distribution scheme, it seemed that the war of currents had been firmly decided in favor of Tesla’s solution. However, a century later has revealed an outmoded and fragile electrical ecosystem, with new energy sources and infrastructures that reposition DC as a primary contender for distribution and consumption. This paper will outline these current challenges, and explore the implementation of practical DC solutions across both the larger power grid and within residential applications

Energy Efficiency of Sustainable Renewable Microgrids for Off-Grid Electrification

Energy efficiency (EE) has a key role to play in the rate of electrification towards decreasing energy poverty around the world. It has benefits to electrified urban and rural areas, as well as off-grid communities. Therefore, in this paper, we explore using empirical data, the impact of EE (as a form of demandside management) on the adoption of renewable microgrids for off-grid electrification in Sub-Saharan Africa. The study shows that improvements in the energy efficiency of commercial and residential appliances will optimize the availability of existing power resources, creating more access to underserved areas. An EE-centric power distribution model will also lead to higher value per energy served to under-served communities through renewable microgrids

Impacts of small-scale electricity systems: A study of rural communities in India and Nepal

This study assesses and compares the benefits of electricity service to households and small enterprises from microgrids, solar home systems (SHS), and the national grid in select rural communities in India and Nepal. Electricity access, in general, leads to reduced kerosene use, more time spent by women on income-generation, and the acquisition of home appliances. However, different types of systems have distinct differences in electricity service conditions. These conditions partly explain why households with SHS exhibit the greatest reduction in kerosene use; why grid-connected households own more appliances; and why electricity access benefits small businesses, but seldom drives key business decisions. The developmental impacts of rural electricity access may benefit from supply standards, greater policy support for investments in productive uses, and further research into the cost-effectiveness of electrification from different supply systems