Optimal sizing of a hybrid mini-grid considering the fuel procurement and a rolling horizon system operation

Abstract

Hybrid mini-grids are promising solutions to foster the universal electricity access in developing countries. While renewable sources, possibly combined with energy storage devices, help in reducing the environmental impact and the operational costs of electricity supply, a backup diesel generator can increase the continuity of service when RES are not available or very discontinuous. The fuel procurement can be a serious issue in rural areas, due to lack of good infrastructures, combined to long distances existing between the mini-grid and the fuel station; however, this aspect is usually disregarded in designing the mini-grid. Moreover, the traditional sizing of rural mini-grids is based on simulating simple operational strategies. Rolling horizon strategies can be more efficient since the system is redispatched also infradaily, thus leading to possible reductions of operational costs and load curtailment. The present paper proposes a novel probabilistic technique for the optimal sizing of a mini-grid, considering both the fuel procurement issues and a short-term rolling-horizon scheduling of resources. This method is applied to a system composed by a photovoltaic plant, a lithium battery, a diesel generator, and a fuel tank, minimizing the net present cost of the system over the project lifetime. A numerical case study is discussed

Methodology for the Energy Need Assessment to Effectively Design and Deploy Mini-Grids for Rural Electrification

“…HOMER can also be used to evaluate poor design choices and operational issues in existing mini-grids [14]. Whereas HOMER considers a single deterministic scenario of load and renewable energy generation, stochastic methods to cope with load and generation uncertainties have been proposed by other applied studies [11,15,16].…”

Multi-Objective Optimization of Off-Grid Hybrid Renewable Energy Systems in Buildings with Prior Design-Variable Screening

“…In [11,[16][17][18] the authors presented a significant review of studies regarding stand-alone HRES. Evidence shows a great variety of design, simulation, control and optimization approaches, as well as available software, such as HOMER (Hybrid Optimization Model for Electric Renewables, HOMER Energy, Boulder, CO, USA), the most used tool for electric energy systems, developed by NREL (National Renewable Energy Laboratory, Golden, CO, USA).…”

Energy Production Analysis and Optimization of Mini-Grid in Remote Areas: The Case Study of Habaswein, Kenya

“…The mini-grid under investigation was then sized using an optimization tool that performs a probabilistic simulation of the operation of different possible size scenarios [11,36]. With this approach, the mini-grid is basically sized by searching the set of components whose yearly operation is expected to be the cheapest one, accounting both for CAPEX and OPEX.…”

“…During the recent years, the combined use of renewable energy sources, especially wind and solar, is becoming increasingly attractive and being widely used as an alternative to fossil fuel energy [9]. Governments therefore ought to regularly evaluate the renewable power development policies in order to effectively promote the application of renewable energy sources [10], especially for off-grid power plants, since the fuel procurement can be a serious issue in rural areas, due to lack of good infrastructure, combined with long distances existing between the mini-grid and the fuel station; however, this aspect is usually disregarded in designing the mini-grid [11].…”

“…Optimal size of the system with the probabilistic method described in [36]. To evaluate the benefits of using a predictive operational strategy instead of the simple load-following procedures implemented in HOMER and in [36], the mini-grid described in the last row of Table 5 was then re-simulated assuming a rolling-horizon infra-daily redispatching strategy of the batteries and of the diesel generator [11]. With this method, every 6 h, the load and the PV power profiles expected for the following 24 h are used by a MILP procedure that optimizes the use of batteries and of the diesel generator for the hours to come, by minimizing short-term operational costs; the capability constraints of power electronics, battery, diesel generator, renewable sources and fuel tank are duly taken into account.…”