Entry: Land Art Generator Initiative 2014
THE CITY AND THE SEA
The annexation and construction of islands; the carving of coastal land into fixed geometries; the mounting of walls and dykes to save dryland from saltwater intrusion: these practices issue from the complex and shifting tensions that mark the boundary between the city and the sea, and define the area of Refshaleøen. Viewed allegorically, this behavior conveys feelings of complexity toward the sea. At once inextricable from Danish myth and affluence, the sea is nonetheless estranged - a thing apart, with no place in the grammar of urban design.
Yet, as the seas rise, the barriers between land and sea face a swelling pressure. RGB Spectrum translates this pressure into power, through osmosis, all the while casting a new role for water in urban placemaking.
A winding, riverine channel courses through the pier, evoking the lost Ladegårdsåen - a stream that once flowed freely from Damhussøen through the city of Copenhagen. The Ladegårdsåen not only replenished The Lakes (Søerne) and supplied the town with water, but functioned as a space to swim, wash, and gather. By the mid 20th century, the Ladegårdsåen was concealed within a pipe beneath the busy streets of Ågade and Åboulevarden, and this unique civic space was lost.
In RGB Spectrum, the Ladegårdsåen is reintroduced as a social catalyst and icon. It doubles as the site’s spatial armature and the the source of osmotic energy production. The channel is divided by a hyper-thin, densely folded, permeable membrane, which separates ocean-fed saltwater from freshwater. The membrane captures the difference in osmotic pressure as fresh water molecules push through the membrane to dilute the briny solution.
RGB Spectrum invokes the Danish tradition of sculpting land along the water’s edge while celebrating the confluence of freshwater and the sea.
The lone byproduct of the osmotic energy-making process, brackish water, is cycled into a network of on-site evaporation pools carved into the pier. The evaporation process is accelerated by excess heat from osmotic turbines, in the form of steam. The salinity of these artificial pools supports a rich biota of salt-tolerant algae and microorganisms that dye the pools a spectrum of brilliant hues corresponding to their salinity. When the water is sufficiently briny, it is cycled back into the osmotic artery to augment osmotic pressure and amplify energy production.
A liminal atmosphere of warm steam and luminous water bodies gives way to a sequence of graduated gathering spaces, paths, and cavities shaped by the elbows of the osmotic artery. Sculptural viewing promontories built with the rubble-aggregate subtracted from the pier allow visitors to observe the osmotic process and the gradient pools from above. This cut and fill strategy creates a massing that extends from one meter below sea level to five meters above, while diminishing the amount of foreign material introduced to the site. The site’s new depth serves a further function - as retention basins for rainfall. Large surface planes composed of gravel and seeded with native grasses provide a natural filter for the water before it enters the retention basin and, eventually, the osmotic artery.
RGB Spectrum is not defined by a single sculpture or installation, but emerges as a composition of artful subtraction, aggregation, and unification that describes a symbiotic coupling of land and water.
RGB Spectrum harnesses the abundance of fresh and saltwater in Copenhagen to produce osmotic power. Freshwater has a typical salinity level of less than 0.5 PPT (parts per thousand), while ocean water ranges from 30 PPT to 50 PPT, and briny water measures above 50 PPT. In the osmotic artery, seawater is combined with a briny solution from onsite evaporation pools and separated from freshwater by a membrane. This super-fine and tightly folded membrane maximizes surface area and, with it, energy production capacity. Unfolded, it stretches to a length of over 30 kilometers.
The difference in osmotic pressure between the salty and sweet liquids drives freshwater through the membrane to dilute the salty solution. This pressure spins a series of turbines embedded in the pier, where energy is generated and stored. Insight from the Statkraft power plant in Tofte, Norway affirms that RGB Spectrum has the capacity to produce 25,000 kWh of electricity.
The resultant mode of energy production is multivalent - each component contributes to the aesthetic and productive value of the site.
The Danish Meteorological Institute anticipates that Copenhagen’s future climate will include more infrequent - but more intense - rainfall. This combination of predicted effects requires infrastructural solutions that are capable of retaining water for longer and, crucially, absorbing more at once. The RGB Spectrum not only retains 100,550 cubic meters of water, but the retention and filtration of water on-site ensures that water is reused and leaves the site cleaner than when it arrived.
The high salinity pools of the RGB Spectrum are contained within concrete basins to prevent very briny water from discharging into the bay. The gradient of fresh to briney water across pools supports a wide range of microorganisms that thrive at different salinities. These include synechococcus, halobacteria, and dunaliella. The pigments inherent in these organisms - chlorophyll, rhodopsin, and phycobiliproteins, among others - lend them their shimmering hues, from pale green to bright chartreuse, deep magenta to cyan blue.
These rich and varied microbiota support a diverse ecosystem of shorebirds, waterfowl, insects, and other wildlife that feed on the algae and organisms living in the salt ponds. Additionally, these microorganisms filter water, thereby regulating water quality and producing a distilled, briny solution that enhances the osmotic process.
The urbanization of water - at once spatial and social - is a critical part of Copenhagen’s civic narrative, and, increasingly, the future narrative of all inhabited coasts. RGB Spectrum reconsiders the meeting of the city and the sea and posits a new language of productive design for the present.