Improving battery lifetime and reducing life cycle cost of a PV/battery system using supercapacitor for remote agricultural farm power application

One of the challenges in utilizing photovoltaic systems in agricultural applications is the cost of batteries. Batteries are often replaced when used for farm power compared to residential applications due to the incessant high current that is drawn from the battery as a result of the nature of operation in agricultural applications. This increases the overall life cycle cost (LCC) of the system, which makes generation of electricity from renewable energy sources unattractive. This paper proposes the use of supercapacitors (SCs) to improve the battery lifetime and reduce the life cycle cost of a standalone Photovotaic (PV)/battery system for a remote farm power application. Two scenarios are created: PV/battery system only (i.e., without SC) and PV/battery/SC (i.e., with SC) for a typical remote agricultural feedmill. The sizes of PV, battery, and SC are optimally matched with the load profile of the feedmill using genetic algorithm, while the battery lifetime was estimated based on Schiffer's technique. The analysis is carried out through simulation in the Matlab™ environment. Some of the key results reveal that PV/battery only has a slightly lower initial capital cost of $5010 compared to PV/battery/SC with an initial capital cost of $5480. However, the battery lifetimes with and without the use of SC are 5 and 2 years, respectively, denoting an improvement of 40% in the battery lifetime when SC is adopted. The LCC values of the PV/battery system with and without SC are obtained to be $6423 and $11 037, respectively, indicating a significant reduction of 58% in the LCC when SC is utilized.