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BLUE ENERGY

70% of the earth comprises of salt water. Blue Energy is a technique for harvesting durable energy from this limitless source using the principle of osmosis. A prerequisite to generate energy from osmosis is a high difference in salinity between sea and fresh water.

Infrastructural works such as the Brouwrsdam or the Afsluitdijk where fresh and salt water are divided by a hard infrastructural line, generate the ideal conditions to harvest energy from this abundant source.

Three central themes form the basis for the scenario: technology [energy from osmosis], ecology [the natural balance between salt and fresh water biotopes] and economy [financial viability through ancillary programs].

Technology
Salt and fresh water are pumped into a ‘black box’ and are allowed to flow next to each other, separated by a membrane. Ionisation exchange occurs thereby generating electrical energy with clean brackish water as a by-product. One m3 of membrane generates sufficient energy to run an average household. How much energy can we derive from the dike using this technology and what are the technical possibilities for integrating this system into the dike? Is it possible to re-use the clean brackish water in some manner?

Ecology
After the floods of 1953 the introduction of dikes in the Dutch Delta altered the natural flow of water resulting in a new biotope for fish and birds. Ecologists have different opinions regarding the effect of the dike on it’s environment. Possibilities are being investigated for making small openings in the dike to allow fish to follow old migration patterns.

This would alter the saline content of the water generating a salt to fresh gradient that is not optimal for osmosis. How to deal with this paradox? Is it possible to generate a system in which salt, brackish and fresh water systems are separated allowing for biological diversity without limiting the possibilities for energy generation through osmosis?

Economy
Electrical energy through osmosis is, at this stage, twenty times more expensive than energy derived from fossil fuels. Predictions indicate that it will take roughly twenty years before blue energy will be as cheap as other, non-durable forms. In order to make the application of durable blue energy financially viable, programs that generate extra revenue will have to be incorporated into the scheme. What programs can be imagined in relation to the economic processes of the region as a whole? What spatial configurations does this lead to? Is it possible to transform the Brouwersdike into the economic engine of the delta?

STATUS: study 2002
DESIGN: Design Atelier NaarZee!, Netherlands Institute of Spatial Planning

-› Wetsus