Smart grid solutions enable the accommodation of wide-scale electric cooking by rural electricity infrastructure

Student thesis: Doctoral Thesis

Abstract

Access to modern energy and clean cooking is being addressed widely in developing countries. By continuing to use traditional cooking methods such as three-stone stove, high level of household (HH) air pollution is created. Which has severe health implications, particularly on women and children. Cooking with electrical devices known as ‘eCook’ are becoming an attractive solution as it offers low carbon and is less harmful to health alternative to biomass. However, energy poverty remains a huge challenge in developing countries, electricity is unreliable in grid-connected areas leading to rolling blackouts and the infrastructure is weak and damaged. Therefore, the main research contributions of this thesis include the development of a novel impact assessment methodology to aid understanding of the technical and techno-economic implications of additional electric cooking demand (eCook) in rural mini-grids in developing countries. where the eCooks are directly connected to the power supply (direct eCook). To assess the design readiness, future design requirements and the potential solutions to increase their adoption without the need for a significant upgrade and reinforcement of the mini-grid network. The other main contribution centres on the modelling and simulation of an innovative control strategy through the introduction of battery-operated cooking devices. The smart eCook battery management system (‘smart’ EBMS) seeks to minimise installed generation capacity required to accommodate ‘new’ mini-grid eCook demand by maximising the utilisation of electricity from the daily PV generation and offsetting peak demand compared to direct eCook. The analyses are carried out on a conventional ‘hub and spoke’ hybrid photovoltaic (PV)/diesel mini-grid topology model to quantify the main network problems. Two network studies are considered where the eCook appliances are directly connected to the power supply. The first investigates the limitations of the mini-grid in terms of the generation capacity available to supply the demand for different levels of eCook penetrations. While the second focuses on the network constraints for different eCook penetrations. The overall results of the second network study show that voltage drop and voltage imbalance issues can be reasonably and affordably addressed by using cables of a larger cross-sectional area. The main issue prohibiting higher penetrations of direct eCook is the limited generation capacity requirements to supply the additional demand. This entailed modelling an innovative ‘smart’ EBMS that maximises the utilisation of electricity from the daily PV generation and offsets peak demand by using a battery-operated eCook. In addition, it actively monitors the state of the grid and decides on battery-operated eCook C-rate set-point required to address the network constraints. The results demonstrate that the ‘smart’ EBMS can alleviate the impact of conventional battery-operated eCook charging on the mini-grid network. It constantly monitors the state of the power grid; when the voltage drops below the allowed limit, the ‘smart’ EBMS detects the problem and adjusts the C-rate of the battery-operated eCooks. This allows the voltage to recover while maintaining the charging regime. Also, it increases the quality of the charging service (QoS), which relates to an increase in the number of battery-operated eCooks recharged daily compared to a network without the ‘smart’ EBMS. An economic affordability assessment methodology is also developed to understand the upcoming cost trend of eCook adoption and to identify the key factors to bridge the affordability gap between the cooking energy cost of conventional fuel and battery-operated eCook. Three main factors need to be considered when estimating the cooking cost: the non-market cost of firewood; ensuring a low mini-grid tariff that is within a range of the national grid tariff and using an optimal battery-operated eCook size with the capability to meet the required demand. When taking these factors into account; for the 2022 analysis, cooking 100% using a battery-operated eCook is in a range of $29–30/month implying that there could be an opportunity for parity when the firewood cost reaches $29/month. The same applies to the cooking prediction costs for 2030, reducing further to $20–21/month. However, if the firewood is harvested sustainably, ensuring it is high quality and dry, it would be difficult for battery eCook to compete. It should be emphasised that this research has relevance to governments, practitioners, and researchers as it gives insights into the current issues and offers possible solutions to achieve clean and affordable energy for all. The main conclusion drawn from this research study is that there is a need for a Head-Heart‑and‑Hands approach to move towards clean cooking for all from both the household (HH) level and mainly from Governments. However, to implement this strategy and for it to be successful all three parts must be implemented together. Unfortunately, this was not always evident during this research. Governments are mostly reluctant to implement or convey strategies or innovations to the consumer and there were insufficient policies to educate HH’s on the short-term and long-term benefits of moving towards clean cooking for all.
Date of Award11 May 2023
Original languageEnglish
Awarding Institution
  • University Of Strathclyde
SponsorsEPSRC (Engineering and Physical Sciences Research Council)
SupervisorScott Strachan (Supervisor) & Stuart Galloway (Supervisor)

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