Technical-economic analysis of grid-connected photovoltaic systems for self-consumption in Ecuador: experimental cases in the coastal and highland regions.

Abstract

Photovoltaic systems (PV systems) connected to the electricity distribution grid and in self-consumption mode are designed to operate in parallel with the conventional electricity supply grid. These systems are based on photovoltaic modules and their operation allows them to supply all or part of the electricity demand of buildings. There are scenarios where the consumption may be less than the PV production, i.e. the PV system produces more electricity than needed. This will result in the generation of surplus electricity, which can be dealt with in three ways: it can be stored in batteries, which entails an extra cost; an anti-spill system can be implemented, which results in the loss of the energy; or the surplus can be fed into the electricity distribution network, and in some cases, it is possible to receive some remuneration. These new scenarios have made it possible for photovoltaic self-consumption to spread around the world at an accelerated pace. It is expected that in the next four years approximately 100 million homes will have photovoltaic systems, representing 25% of the distributed energy produced in the world.

 In Ecuador the existing legislation is very young, it officially started in 2018, through the regulation ARCONEL 003/18 that establishes the technical, commercial and legal conditions for users to implement photovoltaic generation facilities. This regulation was ratified with the "Energy Efficiency Law" published in March 2019. Three years after the publication of the regulation, the Agency for Regulation and Control of Energy and Non-Renewable Natural Resources (ARC) established an update, publishing the regulation ARCERNNR-001/2021. Despite the incentives presented in the regulations, the installation of grid-connected PV systems has a low number of registrations. This may be due to various factors, including administrative procedures, the cost of implementing the systems, and the method of compensation, among others. This research develops a technical-economic analysis of the operation of three self-consumption systems located in the cities of the provinces of Manabi and Pichincha, representative of the coastal and highland regions respectively.

In this analysis, actual data for a full year and the regulatory conditions set by the Agency for Regulation and Control of Energy and Non-Renewable Natural Resources have been used. The technical analysis includes photovoltaic generation curves, electricity demand, self-consumption factors and self-sufficiency. On the other hand, the economic analysis includes the installation costs, the savings generated in the monthly electricity bill and the payback time of the investment. In a complementary way, the normalisation of real data is carried out to establish different scenarios, where the minimum conditions necessary for the profitability of these systems in Ecuador are identified. The results indicate that profitability is achieved for residential and commercial users under certain conditions of building consumption. Finally, recommendations are generated for the appropriate design of new installations and new compensation scenarios are proposed based on the reality of the country, to improve the inclusion of self-consumption systems.