Optimizing Off-Grid Generation in Large-Scale Electrification-Planning Problems: A Direct-Search Approach

Abstract

Off-grid systems play a prominent role in rural electrification planning. The problem of optimizing the generation design of a single off-grid system has received a significant amount of attention in the literature, and several software tools and algorithms have addressed it. However, methods and tools designed for individual mini-grids are not directly applicable to regional planning, where it is necessary to estimate the generation cost of potentially thousands of mini-grids. Conversely, most regional planning tools estimate the generation cost of mini-grids with rules of thumb or analytical expressions. These estimations are useful, but they lack the accuracy necessary to develop a rural electrification plan. This paper presents a method to estimate the generation cost of any potential off-grid system in a large-scale rural electrification planning problem, which is currently implemented in the Reference Electrification Model (REM). The method uses a master-slave decomposition that exploits the structure of the problem and combines continuous and discrete variables. The algorithm is illustrated with a case study that shows that a direct application of a discrete model may lead to suboptimal results in large-scale planning.

Modeling of a Village-Scale Multi-Energy System for the Integrated Supply of Electric and Thermal Energy

“…YCC is calculated as shown by Equation (17), where Cost O&M is the cost of operation and maintenance of the system and Cost f inan is the fixed-rate loan payment, while the other variables represent costs associated with the use of fossil fuels and the cost of losing the unmet load (LL cost ).…”

“…In such contexts, increasing the penetration of locally-available renewable sources would imply reducing the dependency on external fuel imports and the economic instability associated with price fluctuations. In fact, adoption of micro-grids in rural areas for providing access to electricity [7] is a subject greatly explored in scientific literature [15][16][17][18][19][20][21][22][23][24] and that is becoming a more frequently adopted solution in development projects both financed privately or by international organizations [25,26].…”

A Rising Role for Decentralized Solar Minigrids in Integrated Rural Electrification Planning? Large-Scale, Least-Cost, and Customer-Wise Design of Grid and Off-Grid Supply Systems in Uganda

“…REM incorporates electrical constraints and topographical features of the terrain [35] when optimizing the network layout of minigrids and grid extensions. The model simulates the hourly dispatch of off-grid systems when optimizing their generation designs [36], considering the impact of seasonality and accounting for the non-served energy. REM has been already applied in the electrification master plans of Rwanda [37], Mozambique [38], Indonesia [39], Ecuador [40], Colombia [41], Pakistan [42], and Bolivia [43].…”

Joint Optimal Planning of Electricity and Modern Energy Cooking Services Access in Nyagatare

“…REM also works with a high temporal resolution, representing the demand of each consumer and the renewable potential (solar irradiance) with an hourly profile. The model optimizes the generation designs of microgrids and standalone systems using a heuristic method that simulates the hourly dispatch of potential generation designs [51].…”