The global shift towards sustainable practices extends across various domains, including energy generation. Wind energy, a cornerstone of this transition, relies heavily on the efficient operation of wind turbines. This study investigates the impact of contaminants on the longevity and performance of blade bearings in wind turbines. Under real-world conditions, blade bearings frequently operate in suboptimal lubrication environments, attacked by contaminants like wear particles and water. This research, conducted in collaboration with Vattenfall R&D, aims to focus on the specific effects of these contaminants.  Through comprehensive literature reviews and tribological tests, the study evaluates the load in rolling elements, examines the contact conditions between raceways and rollers, and determines the effects of contaminants on wear volume. Findings indicate that most pitch movements in blade bearings are limited to small angles, influencing lubrication requirements and wear patterns. Chloride-based EP additives, probably inactive due to insufficient activation temperatures, show potential for hydrolysis-induced corrosion.  Wear tests suggest that used grease may perform better under certain conditions compared to fresh grease, highlighting the complexity of lubricant performance. Long-term tribological tests show that FUCHS LUBRITECH GLEITMO 585K exhibits better wear resistance compared to Shell Rhodina BBZ in test conditions.  The study underscores the importance of proper lubrication and contamination management in extending blade bearing life. Recommendations include regular grease monitoring and analysis, understanding tribo-corrosion effects, and improving seal compatibility to enhance overall bearing reliability.