One of the great challenges in the transition to an energy system based on renewables is to align the fluctuating energy production to match the patterns of consumption. Fluctuating energy sources such as wind and solar cannot be calibrated to match variations in energy consumption, and as a result these sources are bound to produce power at times of low demand – and to not produce at times of peak demand.

Large-scale energy storage of excess solar and wind power could provide the balancing power necessary to create a renewables-based energy system that does not compromise efficiency, stability or security of power supply.

In some of the world’s mountainous regions, pumped hydro is used to balance the power system. Water is pumped back into the high reservoirs of hydro plants to generate power in periods of high demand. For the world’s many low-lying, flat costal regions, this is not an option. Such areas are often ideally located for wind farms, both on land and offshore – yet today they lack methods for storing large quantities of electricity

 

Artificial energy islands balanced by seawater'
Green Power Island is a visionary concept for constructing artificial energy islands for large-scale storage by means of seawater. It draws inspiration from mountainous countries such as Spain and Norway, which already pump large volumes of water into high altitude reservoirs, and then lead the water back down through turbines to generate electricity in times of peak demand. This relatively simple technique is called pumped hydro.

In level regions with large bodies of water, the technique can be used in an adapted form. In basic terms, a green power island encloses a lagoon-like reservoir, which is emptied using pumps driven by wind and solar produced while demand is low. As consumption rises, seawater is allowed back into the reservoir, driving turbines that generate new power. In this way it is possible to regenerate up to 75% of the energy that went into the process of pumping it empty.

The electricity is initially produced on the island itself by wind turbines or solar-power arrays that float in the reservoir lake. Because the lake is never drained completely, it can also be used for aquaculture, with products destined for human consumption or blue biomass (seaweed or algae).

Behind the project stand Gottieb Paludan Architechts and the Risø National Laboratory for Sustainable Energy under the Technical University of Dennmark, with support from Danish and international advisors. Further research and development will include financial, technical, environmental and design studies.

To read more about the Green Power Island, visit the website: http://www.greenpowerisland.dk/

Related news: Energy storage - A cornerstone in future sustainable energy systems

Source: Gottlieb Paludan Architects

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