A storage system is described where goods are stored in containers (10) and the containers (10) are stored in stacks. Above the stacks runs a grid network of tracks on which load handling devices run. The containers (10) may be provided with one or more of the following services: power, power control, heating, lighting, cooling, sensing means, and data logging means. The provision of these services within individual containers rather than across the system as a whole, allows for flexibility in storage whilst reducing cost and inefficiency.