Impact of Diesel generator limitations in the robust sizing of isolated hybrid Microgrids including PV and batteries

The recent developments in PV and Lion-ion batteries along with the maturity of gensets technology to provide energy to isolated systems has fostered the use of hybrid micro-grids for rural electrification. In this context, the optimal coupling of different technologies and the minimization of the cost to the final consumer are the objects of a number of previous researches. However, the approach usually relies on deterministic linear programming optimizations (LP), which do not allow to model certain non-linearities and limitations of the components. This paper aims at filling this gap by proposing an optimization of such system, with a detailed representation of each component. The case study of an isolated village (Las Misiones, Bolivia) with a peak electricity consumption of 9.2 MW is analyzed. The considered system comprises a diesel generator; a PV array and Li-Ion batteries whose nominal capacities should be optimized. A robust optimization tool is first proposed with an LP formulation and the net present cost as objective function. The basic model is then modified to take into account more complex operating characteristics of a gen-set operating in part-load. To that aim, the LP problem is changed into a mixed integer linear programing formulation. Results indicate that the more detailed constraints influence the final design of the system and negatively impact the total cost.