Green Power Islands: A Solution for Renewable Energy Storage Problems?
A Danish architectural firm is taking a well-known method of energy storage and applying it to renewable energy, turning unused land surrounded by water into Green Power Islands.  The firm, Gottlieb Paludan, is setting up solar and wind farms on these islands then using the surrounding water as energy storage via pumped hydro.


What is Pumped Hydro?

The largest capacity form of grid energy storage today, pumped storage hydroelectricity stores energy in the form of water, pumped from a lower elevation reservoir to a higher elevation.

This is usually done during times of low energy demand, using excess generation capacity to pump the water. During periods of high electrical demand, the stored water is released through turbines.

Is it Efficient?

Yes and no. Most often, pumped hydro storage is used for base-load power generation (thermal, nuclear, coal-fired), which allows energy technologies to run at peak efficiency. When taking into account water evaporation and conversion losses, the method runs at about 70-85% efficiency.

However, a very specific geography is often required for pumped hydro to work — usually abandoned mine shafts or dam sites. The procedure requires a good high-low altitude ratio.

It appears that Gottleib Paludan is using this technology in new ways, namely by connecting it to renewable energy sources.


The Green Power Island Solution:

The Green Power Island is essentially a man-made fake island with a central lagoon. The lagoon is emptied into storage areas via pumps powered by wind and solar.

As consumption rises, water is allowed back into the lagoon via turbines that generate electricity at a remarkable  75% efficiency.

What makes Green Power Island even better is its ability to be interconnected with other solar and wind farms elsewhere, allowing for large-scale renewable energy storage.