Temporal and Spatial Characterisation of Solar Energy Potential in Latvia: The Case of Ventspils and Jelgava

Abstract The study assesses Latvia’s solar energy potential using high-frequency solar irradiation datasets from Jelgava (inland) and Ventspils (coastal). The analysed period covers September 2023 to August 2025, including 69,823 measurements in Jelgava and 69,827 in Ventspils, taken at 10–15-minute intervals. The mean irradiation intensity was 97.2 W/m² in Jelgava and 106 W/m² in Ventspils, while maximum values reached 1095 W/m² and 1097 W/m², respectively. Integrated results indicate annual solar availability of approximately 900–1100 kWh/m²/year in both regions. Seasonal analysis shows very low winter irradiation in Jelgava, with 8–10 W/m² in December–January, while summer peaks occur in June (199 W/m²) and remain high in July–August (170–175 W/m²). The findings confirm that PV generation is technically feasible in Latvia despite its northern latitude. Jelgava demonstrates a higher inland peak potential, whereas Ventspils provides more stable coastal irradiation patterns. The results support regionally optimised PV planning and highlight the need for balancing solutions during the low-irradiance winter months.