Impact of the net-metering policies on solar photovoltaic investments for residential scale: A case study in Brazil

The adoption of renewable energy resources is in the core of energy transition. However, its implementation can be highly impacted by country policies. A limited number of researches investigated solar photovoltaic investments, comparing net-metering rules for distinctive energy consumption levels and different discounted rates, from the investors' point of view. This paper analyzes the impact of Brazilian net-metering rules on solar photovoltaic investments, considering residential scale. The methodology contemplates the development of a Discounted Cash Flow model to calculate Discounted Payback (DP), Net Present Value (NPV), Internal Rate of Return (IRR), and Levelized Cost of Electricity (LCOE) of projects. The case studies consider the impact of Brazilian regulation from net-metering rules (previous, considered, and current), energy consumption levels (Low, Middle, and High), and discount rates (5 %, 10 %, 15 %, and 20 %). The results show that from the previous to current rule the return for investor, on average, decreased 5.77 %. However, this reduction would be of 12.81 % if considered rule was adopted. For the 36 studies carried out, even in the worst case the investments remain viable. Therefore, the existing policy is suitable for the current stage of sector development; minimizing the impacts for energy tariff, distribution companies, consumers, and prosumers.