Solar Energy Potential for the Sustainable Energy Transition in the Republic of the Congo

The Republic of the Congo is facing significant challenges in terms of access to electricity, particularly in the extensive rural and remote areas. A reliable assessment of solar resources and photovoltaic (PV) potential is needed to support the development of decentralized sustainable energy solutions. This study evaluates the potential for photovoltaic electricity production in Brazzaville based on in situ radiation measurements. The potential was extended across the country using satellite data from SolarGIS through calibration, although this requires further validation of satellite data in certain transition zones, ranging from the southern savannas to the dense equatorial forests in the north of the country. Measurements taken over a year at the Cité Scientifique de Brazzaville using LP02 and CS300 pyranometers were compared to SolarGIS estimates using statistical performance indicators. There is better agreement between these sensors, with R2 = 0.80 and an RMSE = 0.47 kWh/m2/day. However, we observed between the SolarGIS data and the LP02 measurements an R2 = 0.91 and an RMSE = 0.17 kWh/m2/day (3.8%), whereas with the CS300 we obtained R2 = 0.77 and RMSE = 0.59 kWh/m2/day (14%), which shows a better performance of LP02 compared with CS300. In terms of photovoltaic energy production, the average photovoltaic solar yield was estimated at 3.9 kWh/kWp/day for the LP02 and 3.5 kWh/kWp/day for the CS300, with an annual yield of approximately 1424 kWh/kWp for the LP02, corresponding to estimated discrepancies in photovoltaic production of 0.14 kWh/kWp/day. Based on this, we estimated that a 50 kWp photovoltaic solar system would produce approximately an annual power of 71,200 kWh, which would supply 285 households for a village. These results confirm both the significant potential of solar photovoltaics for decentralized rural electrification and the usefulness of calibrated SolarGIS data for assessing solar resources in areas with limited site-level data. These efforts align well with the planning and investment needs deployed by the Republic of Congo to ensure sustainable electrification of rural areas (PND 2022–2026; National Energy Pact (NEP) and Mission 300).