Comparative cost-benefit analysis of the energy efficiency measures and photovoltaic generation in houses of social interest in Brazil

There are two approaches to the issue of energy demand in buildings: generating more energy in a clean and renewable way or reducing the energy consumption of buildings through energy efficiency strategies. The question addressed by the article is how far to go with energy conservation and cost-effective measures. In this context, the general objective is to compare energy consumption and photovoltaic generation distributed in single-family homes of interest, through the cost-benefit ratio. 576 models were evaluated and the economic evaluation made for the model with the highest efficiency and the model with the lowest cost. The assessment was carried out using the Net Present Value (NPV), Internal Rate of Return (IRR), and the payback. NPV has not proved to be profitable to efficiency strategies in three scenarios. The only scenario with positive NPV was the scenario in which the interest rate is low and the increase in energy is high. In the case of the photovoltaic system, only one scenario did not demonstrate viability, the scenario with high-interest rates, and a low increase in the price of energy. The same applies to the IRR. With this research it is concluded that, when treated as competitors from the financial point of view, the photovoltaic system presents a better performance in the indicators, being the most convenient for isolated application. Answering the question raised and showing the possibility of cost benefit for a massive implementation of renewable, financially viable clean energy.