Multi-year monitoring and performance analysis of a linear Fresnel solar plant in Spain

Fresnel solar technology represents a promising alternative for thermal energy generation, although its penetration remains limited and no studies based on real plants in continuous operation have been reported. This work presents a multi-year experimental analysis of the performance of a 105.6 m 2 Fresnel facility in southwestern Spain. Data from the main operating variables were collected over several years, including mirror reflectivity and direct radiation. A criterion was established to classify days based on available radiation and operating conditions, in order to select valid days for analysis. Daily and monthly efficiency curves were calculated, and energy production was estimated based on radiation measurements. Monthly average efficiencies ranged from 18% in winter to 27% at the equinoxes and 35% in summer. Maximum hourly values above 50% were observed in June. The annual specific production was 534 kWh/m 2 , comparable to theoretical values reported in previous studies. The maximum daily generation exceeded 300 kWh in the summer, while monthly production ranged from 1100 kWh in December to 9700 kWh in July. Sunny days (26.6% of the total) accounted for 42.5% of the annual energy. The study provided a characterization of the seasonal behaviour of Fresnel technology under continuous operation, delivering key experimental insights to reduce barriers and foster its integration into industrial processes. • First multi-year monitoring and performance analysis of a Fresnel solar plant. • Real daily and monthly efficiency curves and estimation of energy production. • Average efficiencies of 18% in December, 27% in the equinoxes and 35% in June. • Annual specific production of 534 kWh/m 2 , 42.5% corresponding to sunny days.