Integration of Photovoltaic Systems With Firstand Second-life Batteries: a Technical-economic Case Study in Brazil
Abstract
This study evaluates the technical and financial feasibility of implementing three renewable energy systems on the Universidade Federal de Santa Catarina main campus in Florianópolis, SC. The feasibility was assessed by analyzing Net Present Value (NPV), Internal Rate of Return (IRR), Discounted Payback, and Levelized Cost of Energy (LCOE). The evaluated configurations included: i ) a solar photovoltaic (PV) system; ii ) a system comprising PV coupled with a first-life Battery Energy Storage System (BESS); iii ) a PV system with a second-life BESS. In order to address uncertainties related to battery pricing and the operational lifespan of second-life batteries, the study first compared IRR across scenarios ranging from 30% to 70% of a first-life BESS cost and one to up to six battery replacements, while assuming a fixed Minimum Attractive Rate of Return (MARR) of 14%. A second analysis compared NPV, IRR, payback, and LCOE for five specific scenarios over a 25-year projection with a variable MARR. Although the standalone PV system demonstrated the lowest LCOE, the PV + BESS first-life system demonstrated superior financial attractiveness due to a higher NPV. PV + BESS second-life systems surpassed the PV + BESS first-life system in financial viability when the second-life battery cost was 50% or less of the first-life battery cost, provided the project required at most three replacements. The PV + BESS second-life (30% cost/1 replacement) scenario presented the best NPV, TIR and payback. Inflation and tariff adjustment indices were not considered for the financial analysis.
Keywords
Second-Life Battery Systems, Hybrid system, Battery energy storage system, Photovoltaic Systems, Financial Feasibility