Assessment of Impacts of Climate Change on Hydropower-Dominated Power System—The Case of Ethiopia

The Ethiopia energy mix is dominated by hydro-generation, which is largely reliant on water resources and their availability. This article aims to examine the impacts of severe drought on electric power generation by developing a Drought Scenario. OSeMOSYS (an open source energy modelling tool) was used to perform the analyses. The results were then compared with an existing reference scenario called “New Policy Scenario”. The study looked at how power generation and CO2 emissions would be altered in the future if reservoir capacity was halved due to drought. Taking this into account, the renewable energy share decreased from its 90% in 2050 to 81% in 2065, which had been 98% to 89% in the case of New Policy Scenario. In another case, CO2 emissions also increased from 0.42 Mt CO2 in 2015 to 7.3 Mt CO2 in 2065, a 3.3 Mt CO2 increase as compared to the New Scenario. The results showed how a prolonged period of drought would reduce the river flows and lead to an energy transition that may necessitate the installation of other concurrent alternative power plants. The study suggested ways to approach energy mix, particularly for countries with hydro-dominated power generation and those experiencing drought

Exploring long-term electrification pathway dynamics: a case study of Ethiopia

The Open Source Spatial Electrification Tool (OnSSET) is extended to provide a long-term geospatial electrification analysis of Ethiopia, focusing on the role of grid- and off-grid technologies to increase residential electricity access under different scenarios. Furthermore, the model explores issues of compatibility between the electricity supply technologies over time. Six potential scenarios towards universal access to electricity in the country are examined based on three pathways; the Ambition pathway sees high demand growth and universal access achieved by 2025, the Slow Down pathway follows a lower demand growth with a slower electrification rate and with a higher share of off-grid technologies, and the Big Business pathway prioritizes grid electricity first for the industrial sector, leading to slower residential electrification. The results show a large focus on grid extension and stand-alone PV deployment for least-cost electrification in case of low grid-generation costs and uninhibited grid expansion. However, in case of a slower grid rollout rate and high demand growth, a more dynamic evolution of the supply system is seen, where mini-grids play an important role in transitional electrification. Similarly, in the case where grid electricity generation comes at a higher cost, mini-grids prove to be cost-competitive with the centralized grid in many areas. Finally, we also show that transitional mini-grids, which are later incorporated into the centralized grid, risk increasing the investments significantly during the periods when these are integrated and mini-grid standards are not successfully implemented. In all cases, existing barriers to decentralized technologies must be removed to ensure off-grid technologies are deployed and potentially integrated with the centralized grid as needed

Amélioration de la fiabilité de l'alimentation électrique par le développement d'une solution multi-sources sur un réseau électrique faible

Les pannes de réseau stochastiques, fréquentes et de longue durée, sont très courantes dans les pays en développement, ce qui pose un problème insupportable de fiabilité de l'alimentation électrique. Les clients sont souvent obligés d'utiliser des générateurs diesel pour surmonter ces pannes imprévisibles et récurrentes. Cette thèse propose un système multi-source solaire photovoltaïque et batterie intégré à un réseau faible basé sur des données de pannes stochastiques enregistrées et un profil de charge. L'objectif de dimensionnement est de trouver le meilleur compromis entre les contraintes technico-économiques, d'assurer la continuité de l'approvisionnement (réduction des pannes) et la minimisation du coût de l'énergie, ce qui met en œuvre une optimisation de dimensionnement multi-objectifs pour obtenir un ensemble de solutions Pareto optimales. Ce travail porte également sur la modélisation et la simulation stochastiques des pannes de réseau. Deux modèles présentant les avantages d'une mise en œuvre minimale sans nécessiter de données détaillées sur les pannes et la capacité de prendre en compte les événements extrêmes dans les pannes sont développés. Le modèle de Markov (matrice de transition de Markov) est capable de capturer les répartitions jour-nuit démontrées dans le test de périodicité. Le modèle de Weibull est capable de prendre en compte de manière précise les événements extrêmes des pannes tels que les durées de pannes longues mais moins fréquentes. Les résultats nous permettent également de tester l'efficacité et la performance du système multi-source (PV-batterie) conçu sur un grand nombre de profils de pannes de scénarios potentiels réalisables pendant la durée de vie du système renouvelable.Frequent and long-duration stochastic grid outages are very common in developing countries, thus posing unbearable power supply reliability problem. Customers are often forced to use diesel generators to overcome these unpredictable and recurrent outages. This thesis proposes a solar photovoltaic and battery multi-source system integrated to a weak grid based on a real recorded stochastic outage data and load profile. The sizing objective is to find the best trade-off between the techno-economic constraints of ensuring the continuity of supply (outage reduction) and minimization of the cost of energy which implements a multi-objective sizing optimization to obtain a set of Pareto optimal solutions. This work also deals with stochastic grid outage modeling and simulation, at which two models with advantages of minimal implementation without requiring a detailed outage data and ability to take into account extreme events in outages are developed. The Markov model (Markov Transition Matrix) is able to capture the day-night repartitions demonstrated in the periodicity test. The Weibull model is able to accurately take into account extreme outage events such as long but less frequent outage durations. The results also allow us to test the effectiveness and performance of the designed multi-source (PV-battery) system on a large number of outage profiles of potential feasible scenarios over the life span of the renew-able system

Amélioration de la fiabilité de l'alimentation électrique par le développement d'une solution multi-sources sur un réseau électrique faible

Frequent and long-duration stochastic grid outages are very common in developing countries, thus posing unbearable power supply reliability problem. Customers are often forced to use diesel generators to overcome these unpredictable and recurrent outages. This thesis proposes a solar photovoltaic and battery multi-source system integrated to a weak grid based on a real recorded stochastic outage data and load profile. The sizing objective is to find the best trade-off between the techno-economic constraints of ensuring the continuity of supply (outage reduction) and minimization of the cost of energy which implements a multi-objective sizing optimization to obtain a set of Pareto optimal solutions. This work also deals with stochastic grid outage modeling and simulation, at which two models with advantages of minimal implementation without requiring a detailed outage data and ability to take into account extreme events in outages are developed. The Markov model (Markov Transition Matrix) is able to capture the day-night repartitions demonstrated in the periodicity test. The Weibull model is able to accurately take into account extreme outage events such as long but less frequent outage durations. The results also allow us to test the effectiveness and performance of the designed multi-source (PV-battery) system on a large number of outage profiles of potential feasible scenarios over the life span of the renew-able system.Les pannes de réseau stochastiques, fréquentes et de longue durée, sont très courantes dans les pays en développement, ce qui pose un problème insupportable de fiabilité de l'alimentation électrique. Les clients sont souvent obligés d'utiliser des générateurs diesel pour surmonter ces pannes imprévisibles et récurrentes. Cette thèse propose un système multi-source solaire photovoltaïque et batterie intégré à un réseau faible basé sur des données de pannes stochastiques enregistrées et un profil de charge. L'objectif de dimensionnement est de trouver le meilleur compromis entre les contraintes technico-économiques, d'assurer la continuité de l'approvisionnement (réduction des pannes) et la minimisation du coût de l'énergie, ce qui met en œuvre une optimisation de dimensionnement multi-objectifs pour obtenir un ensemble de solutions Pareto optimales. Ce travail porte également sur la modélisation et la simulation stochastiques des pannes de réseau. Deux modèles présentant les avantages d'une mise en œuvre minimale sans nécessiter de données détaillées sur les pannes et la capacité de prendre en compte les événements extrêmes dans les pannes sont développés. Le modèle de Markov (matrice de transition de Markov) est capable de capturer les répartitions jour-nuit démontrées dans le test de périodicité. Le modèle de Weibull est capable de prendre en compte de manière précise les événements extrêmes des pannes tels que les durées de pannes longues mais moins fréquentes. Les résultats nous permettent également de tester l'efficacité et la performance du système multi-source (PV-batterie) conçu sur un grand nombre de profils de pannes de scénarios potentiels réalisables pendant la durée de vie du système renouvelable

Assessment of Impacts of Climate Change on Hydropower-Dominated Power System—The Case of Ethiopia

The Ethiopia energy mix is dominated by hydro-generation, which is largely reliant on water resources and their availability. This article aims to examine the impacts of severe drought on electric power generation by developing a Drought Scenario. OSeMOSYS (an open source energy modelling tool) was used to perform the analyses. The results were then compared with an existing reference scenario called “New Policy Scenario”. The study looked at how power generation and CO2 emissions would be altered in the future if reservoir capacity was halved due to drought. Taking this into account, the renewable energy share decreased from its 90% in 2050 to 81% in 2065, which had been 98% to 89% in the case of New Policy Scenario. In another case, CO2 emissions also increased from 0.42 Mt CO2 in 2015 to 7.3 Mt CO2 in 2065, a 3.3 Mt CO2 increase as compared to the New Scenario. The results showed how a prolonged period of drought would reduce the river flows and lead to an energy transition that may necessitate the installation of other concurrent alternative power plants. The study suggested ways to approach energy mix, particularly for countries with hydro-dominated power generation and those experiencing drought

Exploring long-term electrification pathway dynamics : a case study of Ethiopia

The Open Source Spatial Electrifcation Tool (OnSSET) is extended to provide a long-term geospatial electrifcationanalysis of Ethiopia, focusing on the role of grid- and of-grid technologies to increase residential electricity access underdiferent scenarios. Furthermore, the model explores issues of compatibility between the electricity supply technologiesover time. Six potential scenarios towards universal access to electricity in the country are examined based on threepathways; the Ambition pathway sees high demand growth and universal access achieved by 2025, the Slow Down pathway follows a lower demand growth with a slower electrifcation rate and with a higher share of of-grid technologies,and the Big Business pathway prioritizes grid electricity frst for the industrial sector, leading to slower residential electrifcation. The results show a large focus on grid extension and stand-alone PV deployment for least-cost electrifcationin case of low grid-generation costs and uninhibited grid expansion. However, in case of a slower grid rollout rate andhigh demand growth, a more dynamic evolution of the supply system is seen, where mini-grids play an important rolein transitional electrifcation. Similarly, in the case where grid electricity generation comes at a higher cost, mini-gridsprove to be cost-competitive with the centralized grid in many areas. Finally, we also show that transitional mini-grids,which are later incorporated into the centralized grid, risk increasing the investments signifcantly during the periodswhen these are integrated and mini-grid standards are not successfully implemented. In all cases, existing barriers todecentralized technologies must be removed to ensure of-grid technologies are deployed and potentially integratedwith the centralized grid as needed.QC 20231006</p