Integration of an off-grid solar-PV-battery system after grid connection using model predictive control: A case study in Kenya

Abstract

Due to low rates of grid access in many countries in Sub Sahara Africa (SSA), many households with the ability to pay rely on off-grid stand-alone systems for their electricity supply. However, the arrival of the grid in households previously served by these off-grid systems comes with technical integration challenges considering that currently many African countries do not have grid-feed-in policies for small micro-generation. The problem is further complicated by a lack of unified industry standards of practice for deployment of microgrid control systems, leading to suboptimal use of distributed generation assets. In this paper, model predictive control (MPC) algorithm is employed to solve the dispatch problem of a grid connected solar PV-Battery microgrid without grid feed in option. The proposed model is applied to a case study in Kenya and its performance compared with the switched control strategy currently implemented at the case study site to test the economic gains of the MPC. We find that the investment required to implement the MPC algorithm has a payback period of about 7 years.