Sustainable Rewe supermarket grows herbs and fish on its roof

German supermarket chain Rewe has just opened a new generation ecological “Green Farming” supermarket. The circular fish and herb farm on the roof is particularly noteworthy. 

Wood and glass

The supermarket of the future can be found in the German city of Wiesbaden since last Thursday. Supermarket chain Rewe opened a new, sustainable branch there. The architecture alone is striking, with a supporting structure made of wooden columns and a unique vaulted structure that continues into the store. More than 700 tonnes of CO2 are stored by the approximately 1,100 cubic metres of native softwood. In 30 years, the wood will have grown back and the CO2 balance will be in balance.
 

The store has plenty of daylight thanks to glass walls and an atrium, and it uses intelligent cooling and heating technology that runs on 100% green electricity. Energy consumption is 40% lower than in a typical supermarket. The focus is on fresh and local products: local suppliers can offer their products in specially designed market stalls.

Closed loop

But what is particularly special about this green building of the new generation is the integrated city farm with a basil nursery and a fish farm under a glass greenhouse on the roof, visible to shoppers. Rewe will grow some 800,000 basil plants and 12 tonnes of fish meat (perch) annually here, which will also supply other supermarkets in the region.
 

This is an advanced example of ‘aquaponics’, a circular concept that combines the cultivation of plants with the rearing of freshwater fish in a closed circuit. The fish and the plants share the same water: algae in that water are the main source of nutrition for the fish, and bacteria convert the fish excrement into food for the plants. As a result, there is no need to change the water. A very sustainable concept, therefore, that generates hardly any waste.