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In this study, a new resilience-based framework is presented for multi-period simultaneous transmission and substation expansion planning (ST&SEP) considering extreme weather-related events (EWEs). The formation of the proposed planning framework falls into a tri-level optimisation problem with the aim of strengthening power network resilience in response to the EWEs. In the lower-level problem, short-term remedial corrective strategies of the independent system operator (ISO) after the EWEs are determined by applying network reconfiguration and generation redispatch. In the intermediate-level problem, an enhanced scenario-building approach is developed to model and analyse the EWEs, as non-random uncertain events, and their subsequent detrimental effects using the notion of the fragility curves corresponding to power network components. In the upper-level problem, however, long-term remedial preventive strategies of the ISO, as network planner, after the EWEs are obtained through integrated decisions between multi-period ST&SEP and transmission switching equipment planning. The newly proposed planning framework is formulated as a large-scale mixed-integer non-linear tri-level optimisation problem and is solved by a powerful symphony orchestra search algorithm in order to obtain the final optimal solution. The proposed planning framework is examined on the real-world large-scale Iranian 400-kV power transmission network and its profitableness is assured by thorough simulation studies. [ABSTRACT FROM AUTHOR]

Renewable energy is a rapidly growing environmental‐friendly alternative for electricity generation, which will supersede using fossil fuels in the near future. Renewable‐based generation is usually located at remote areas, and the large‐scale generated power is required to be transmitted to the main load centres; thus, the main challenge facing the bulk power transmission is the precise determination of the most appropriate transmission option. This study presents a comprehensive techno‐economic study for the selection of the adequate transmission option for large‐scale power transmission. The proposed work aims to study different transmission alternatives to transfer 10,000 MW of renewable generated power to the load centres in the central region of Saudi Arabia. Different high‐voltage AC (HVAC) voltage levels such as 725 and 500 kV, and high‐voltage DC (HVDC) technologies are considered as alternatives, and a techno‐economic evaluation of each option is presented. Moreover, detailed comparisons between different HVAC and HVDC technologies are introduced from technical, economic, and environmental perspective. The presented study, comparisons, and the subsequent recommendations are helpful for the network planner to evaluate different extra high‐voltage (EHV) and AC/DC transmission options in terms of accessibility, load‐carrying capability, efficiency, reliability, stability, environmental impact, and economics. [ABSTRACT FROM AUTHOR]

The lack of access to electricity in developing countries necessitates spatial electricity planning for guiding sustainable electrification projects that evaluate the costs of centralized systems vis-a-vis decentralized systems. Heuristic approaches have been widely used in such electrification problems to find feasible, cost effective solutions; however, most of the time global optimality of these solutions is not guaranteed. Our paper through its modeling approach provides a new methodology to find the least cost solution to this electrification problem. We model the spatial network planning problem as Prize Collecting Steiner Tree problem, which would be a base for a decision support tool for rural electrification. This new method is systematically assessed using both randomly generated data and real data from rural regions across Sub-Saharan Africa. Comparative results for the proposed approach and a widely used heuristic method are presented based on computational experiments. [ABSTRACT FROM AUTHOR]

This study examines the least-cost technology option for increasing electricity access in two states in Nigeria where electricity access rate is below 20% i.e. Taraba and Yobe within a 10-year investment period. We employ the Network Planner – a web-based decision support program which integrates geospatial information with socio-economic, demographic and energy demand information, and compare three electrification options: grid-extension, mini-grid diesel-based system, and stand-alone option which uses solar PV and a small diesel generator. The result shows that grid-extension is the least-cost option for 98.7% and 89.5% of the demand centers in Taraba and Yobe respectively. [ABSTRACT FROM AUTHOR]

Abstract: In this study, the Network Planner, a decision support tool for exploring costs of different electrification technology options in un-electrified communities, was used to model costs and other inputs for providing electricity to 2600 un-electrified communities in Ghana within a 10-year planning period. The results show that the cost-optimized option for majority of the un-electrified communities will be grid connection, accounting for more 85% of the total un-electrified communities in each region. The total cost of electrification (which includes initial and recurring) at 100% penetration rate totalled US$ 696million with a breakdown as follows: US$ 592million for grid electrification, US$ 47million for off-grid electrification and US$ 58million for mini-grid compatible communities. Sensitivity analysis shows that model scenarios with higher electricity demand and higher household penetration rate generally recommend a larger percentage of communities for grid electrification, rather than off-grid or diesel mini-grid. One important aspect of this modelling approach is that it predicts costs for different electricity generation technologies for each of the communities involved and thus gives the planner the freedom to explore the most cost-effective technology based on existing conditions in the community and price trend of electrification inputs during the planning period. [Copyright &y& Elsevier]

This paper critically examines the literature on the grid-offgrid debate and discusses the role of and the relationship between different electricity access options through a synthesis and critical reflection. This paper finds that models using greater resolution and capturing low voltage distribution infrastructure appear to recommend decentralised electricity solutions, whereas central grid extension emerges as the preferred outcome of more aggregated analysis, concentrated population clusters and for higher demand scenarios. However, model results are seriously influenced by assumptions, data limitations, technology choice options, and model flexibility. Exclusion of cost of generation for grid systems, lack of village level information, inherent bias towards scale and type of technology, and absence of social equity considerations in the analysis remain major weaknesses of the existing models. Universal electrification requires a strong leadership and an enabling environment. An appropriate organizational set-up, a robust regulatory framework with reporting and evaluation oversight and a more inclusive approach to promote alternative options are vital ingredients. Power sector decarbonization pathways may affect electrification choices but our understanding is limited or lacking. Further work is required to develop a programmatic approach to delivery and more affordable and fairer outcome for all. • The paper presents the up-to-date review of the debate on grid and off-grid electrification. • We find a strong leadership and an enabling environment is essential for universal electrification by the year 2030. • Appropriate organizational set-up, robust regulatory framework and shift from grid-centric focus to a more inclusive approach to promote alternative options is equally important. • Important to develop a programmatic approach to delivery and more affordable and fairer outcome. [ABSTRACT FROM AUTHOR]