Estudo de recuperação energética em sistema de abastecimento de água através de bombas funcionando como turbinas. Estudo de caso: cidade de Elói Mendes

Abstract

The use of the potential energy embedded in water supply systems through Pumps as Turbines (PATs) is an alternative that has been showing technical and economic viability due to the reduced cost of the pumps used. However, the system implementation may become economically unviable due to low potential energy available at each point and the need to project on-site infrastructure. In order to ease of maintenance, safety and guarantee of the pressure established in technical standards it is necessary to contain equipment such as drawer, filter, water meter and Pressure Reducing Valve (PRV) registers in a by-pass system contained in a protection box, which can lead to higher deployment costs. In view of the referenced problems, this paper proposes to analyze the economic feasibility for the installation of BFT and its attached equipment, considering the available potential energy, the present infrastructure, the installation cost and the future energy generation for each section studied. This analysis will be performed by calculating the Net Present Value (NPV), Internal Rate of Return (IRR), Levelized Cost of Electricity (LCOE) and payback, measuring three scenarios with different infrastructure levels on site. The ideal scenario, that considers the existence of the entire infrastructure, obtained the result of R$ 7,251.17 (NPV), 21% of IRR, R$ 0.55/kWh levelized cost of electricity and approximately payback in six years, with power generation range of 0.11 kW up to 0.32 kW and annual generation of 1,772,81 kWh. The scenario that only presents civil works as existing infrastructure did not present deployment feasibility, resulting in a R$ 12,653.10 demage, 2% of IRR and Leveled Cost os Energy os R$ 1.58/kWh. The real scenario, which depends on the installation of the entire infrastructure, also did not present deployment feasibility, resulting in a R$ 22,714.19 damage, -1% of IRR and R$2.10/kWh Levelized Cost of Electricity (LCOE).