Many units in the DPRK have built solar greenhouses on roofs of buildings to get much benefit.

The Pyongyang Dental Hygiene Products Factory built two solar greenhouses on the roof of a workshop building to produce vegetables.

Those greenhouses have introduced the soilless cultivation method by nutrient solution and the hydroponic cultivation technology, in which all the processes are based on integrated control system.

And water tanks of tens of cubic metres have been made in the greenhouses to breed catfish, tilapia and Ryongjong fish.

The factory has set up solar panels and solar water heaters in sunny places and is making an effective use of electricity and hot water for cultivation of crops and management of greenhouses.