An integrated approach to decentralized energy systems planning for developing countries

This thesis focuses on the problem of global access to energy for developing countries and provides a thorough analysis of renewable-based mini-grid systems as a solution. In the first section an intensive literature review shows current energy trends and challenges, with a special outlook on Sub-Saharan Africa. The energy forecast situation is assessed by combining data about electric consumptions patterns with an analysis based on the energy indicators for sustainable development issued by International Agencies. A proven methodology for the energy need assessment of rural communities is presented, aiming at obtaining reliable input data for the mini-grid development. This helps in reducing both the financial challenges by mitigating the uncertainties in electricity demand and the technical challenges by contributing to adequately size off-grid power generation systems, with a view to boost toward a common overall objective of mini-grid’s optimization methods and tools. Based on methodology outputs an integrated approach for system design and planning is developed, taking into account techno-economic trade-off and system reliability and flexibility. Design process optimization is carried out through simulation of different combination of generation (PV, Wind, Hydro, multi-source) and storage systems (lead-acid, lithium, vanadium flow, flywheel). Distribution grid constraints have been addressed as well, including last-mile connections and users’ wiring, in order to have an holistic vision in the design phase. Such integrated approach requires to adopt appropriate operation strategies to face real time power quality (voltage and frequency) fluctuations along with an effective capability to meet off-takers demand. Dump loads, device controllers and management options are discussed for both supply-side and demand-side. The thorough analysis looks at economic aspects, therefore different operating strategies are investigated, and business performance has been deeply analysed and discussed. On a view to a global evaluation impact assessment, last part of the thesis focuses on sustainability analysis: beyond economic impact, other direct/indirect effects of mini-grids on environment and target communities are outlined. The tool used for Monitoring and evaluation of mini-grid is the Social Return on Investment ( SROI), by adding a wide set of key indicators to measure monetized effects on education, health, security, environment and economy. The combination of all methodologies and strategies aims at improving the systems design and operation, helping reduce capital expenditures and operating costs, thus allowing for a lower Levelized Cost of Energy over project’s entire lifecycle