Portugal's climate exhibits a Mediterranean nature with some continental attributes, characterized by significant temperature fluctuations. The average yearly precipitation, around 561 mm, is marked by notable year-to-year variability, with alternating periods of abundant rainfall and extreme drought. The intensity of rainfall is also erratic, occasionally exceeding 100 mm in a single day. In Alentejo, monthly sunshine averages approximately 150 hours during November, December, January, and February, whereas July and August can see more than 350 hours of sunshine. Alentejo experiences an annual insolation ranging from 2600 to 3000 hours. The region's yearly Direct Normal Irradiation (DNI) availability fluctuates between 1918 kWh/m2/year and 2097 kWh/m2/year. This DNI data is vital for evaluating the financial feasibility and precise performance analysis of Concentrating Solar Power (CSP) systems over their operational lifespan.
Forecasts for available feedstock in Alentejo range from 653.3 kt/year for forestry biomass to 1416.3 kt/year for agricultural residues. Soil erosion rates in eastern Alentejo show considerable variations based on land use, with crops displaying higher erosion rates. Factors such as tillage direction influence observed erosion rates. Vertical fallow land sees the highest erosion (964 kg/ha/year), followed by wheat (90 kg/ha/year) and horizontal fallow (66 kg/ha/year). Erosion is less pronounced in areas with spontaneous vegetation (3 kg/ha/year), Quercus (4 kg/ha/year), and pine (7 kg/ha/year).
Addressing soil management, pasture areas pose a significant concern. Roughly 51% (2 million hectares) of Agricultural Land Use is permanent pastures, mainly rainfed. Of this, 68% (1.36 million hectares) consists of pastures that have never undergone improvement interventions. As a result, these soils exhibit compromised physical, chemical, and biological traits. They tend to be acidic, possess low effective thickness often coupled with rocky outcrops, and exhibit structural issues affecting water storage and drainage, leading to low water retention capacity. Organic matter content is also meager (<0.5%), impacting microorganism activity and nutrient cycling. Imbalances in certain minerals, particularly the Mg/Mn ratio, and limited cationic exchange capacity further contribute to their frailty. These characteristics render the soils vulnerable to climate change impacts and prolonged dry periods, especially during spring. Furthermore, due to their limited production potential and uneven biomass distribution throughout the year, these soils are susceptible to water erosion for most of the year.