In 2017, power plant operator Voltalia SA commissioned a 4MWp solar plant in Oiapoque municipality, in the state of Amapá, Brazil, in the Amazon region of Brazil, and since has been using Reuniwatt’s irradiance forecasting for anticipating solar fluctuations.

Renewing the power supply of Oiapoque

Engaging wind and solar technology manufacturers, already operating Diesel-powered minigrids in Brazil have been slowly changing towards a more sustainable type of power generation by deploying hybrid systems, i.e. electronically controlled combinations of diesel, solar and wind systems with battery storage.
Voltalia has developed a portfolio of renewable projects in Brazil, amongst which there is the largescale Serra Branca cluster including Voltalia’s VSM1&2 wind farms (291MW in total, and VSM3 with further 70MW planned) and on the other hand Oiapoque (hybrid thermal/solar/hydro), where Voltalia inaugurated its first solar plant in Brazil after winning a bid in 2014 for the town of 24 000 inhabitants not connected to the national electricity grid.
Being the only competitor to offer a hybrid power plant scheme for this remote location, Oiapoque has become a flagship project for power plants with a diverse multi-energy-strategy. Such projects depend on the renewable power producer carefully selecting the best sites and technology from wind, solar, hydro and biomass, and thus produce cleaner and cheaper electricity than the one generated by the diesel generators. In Oiapoque, a 4MWp PV plant is combined with a 12MWp thermal unit, and a 7.5 MW hydroelectric plant will be commissioned in 2021 at the latest.

Associating three sources of energy in one power plant

Associating three sources of energy requires a lot of expertise by the teams behind the power plant. The PV installation in Oiapoque helps optimize the operating cost of the power plant and reduce diesel fuel consumption, and overall helps to ensure a greener, more sustainable electricity production .
Once built, the hydropower plant will be given priority for power production, while the thermal unit will ensure additional production when necessary. The hydropower plant will help reduce greenhouse gas emissions even further, allowing Oiapoque municipality to be proud of generating up to 90% of their energy supply from renewable sources.
But a more environmentally sound energy supply based on renewables, notably PV and wind, is always depending on natural fluctuations of the resources. This fact requires a well thought-through strategy to encounter periods of lower output power from renewable sources and peak load times, including additional energy storage to complete the system and means to estimate power outputs from renewable sources in advance, and regulate the power plant accordingly. Such measures also help reduce fuel consumption, which again results in a smaller environmental impact of the process.

Irradiance forecasting for a sustainable city

During the past decade, the demand for greener electricity production has been constantly on the rise. The Oiapoque project, operating since 2017, is the first hybrid system in the world to include three sources of energy as well as an all-sky imager for forecasting in the next minutes. Thanks to Sky Cam Vision™, solar fluctuations in Oiapoque can be anticipated, with the images taken and being calculated into irradiance level forecasts by the embedded computer. Therefore, a steep reduction of solar production caused by the movement of the clouds can be detected in time in order to optimize plant operations, and allows to run diesel generators only when needed. At the same time it allows to get out the maximum use of the PV installation, by minimizing curtailment of generated energy during sunshine hours. Today, 17% of the city’s annual consumption can be covered from solar power, without endangering the microgrid’s stability. Reuniwatt is proud to support this sustainable project and be part of its success story.

To learn more about this sky cam application, download the brochure on our flagship project now:

About Reuniwatt (
Reuniwatt is a major player of the solar radiation and cloud cover assessment and forecasting. Based on solid Research and Development works, the company offers reliable products and services intended for professionals of various fields, making the best out of two key facets of the meteorology: atmospheric physics and data sciences. A particular focus has been placed on solar energy forecasting, while developing cutting edge solutions to improve the short-term prediction of the solar resource.
The company has won many grants, including H2020’s SME Phase 1 programme, which makes Reuniwatt a European Champion with regard to innovation.