REDstack

REDstack BV‘s mission is to expand its position in the field of RED and ED process technology and membrane stacks on the global market.
REDstack focuses on two market segments:

• Reverse ElectroDialysis (RED) for renewable energy generation
• ElectroDialysis (ED) for desalination of various types of salt and brackish water streams

REDstack originated as a spin-off company from the water technology institute Wetsus. The theme “Blue Energy” started there in 2005, with the aim of generating energy from fresh and salt water. It soon became clear that this is a promising development. That was the reason for a number of Wetsus participants to set up REDstack. REDstack is a company with W&F Technologies BV as shareholder.

Reverse ElectroDialysis (RED)
REDstack is working fully and successfully on the development, upscaling and future marketing of the generation of energy from differences in salinity, often referred to as Salinity Gradient Power (SGP). This form of energy – often now also referred to as Blue Energy – was first described as a principle in 1954.

The driving force is derived from nature. Nature wants to level out differences. REDstack uses the difference in salt concentration as the driving force for ion transport through the membranes. By alternately stacking two types of membranes, the positive and negative ions from the salt water are forced to flow in two directions, creating a potential difference. This potential difference is converted into electric current in a so-called “RED stack”.

Wetsus and REDstack have translated this principle into an actual extraction method that is technically sound, stable and intact and that is accepted by users in terms of price. That is the source of REDstack’s mission.

The technology has been extensively tested in the trial and development location on the Afsluitdijk. REDstack has its plans ready for a serious upscaling of its system, with which it wants to take the final step towards large installations with end users in a commercial process. The funding for this is now being prepared.

ElectroDialysis (ED)
ED (ElectroDialysis) is a technology that produces fresh water (including drinking water) from salt or brackish water. By also creating a potential difference in a stack with stacked membranes – now called an “ED stack” – the ions from the salt water are forced to move through the membranes, whereby desalination is achieved.

REDstack focuses on applications for some market segments in the ED market:

• ED for brackish water desalination as a way of producing cheap drinking water
• ED for desalination of cooling tower water
• ED for achieving “Zero Liquid Discharge” in industrial processes, whereby by recovering water and valuable components a waste reduction is achieved, which reduces the impact on the environment
• ED for seawater desalination

Products
REDstack focuses on supplying stacks and process engineering, and process installations are supplied together with sister company Pure Water Group (PWG).