Buoy-150 is a modern buoy system for environmental monitoring of water quality in lakes, reservoirs or rivers. Flexibility, robustness, easy servicing access and protection for vandalism have been the main driving forces during the development of Buoy-150. Beside solar power, the Buoy-150 can be equipped with fuel cells (using a dual cartridge) for operations in areas of low sunshine or in applications with higher power consumption. All sensors, batteries, controller, cables, etc. are safely mounted inside the Buoy-150.