Floating solar islands: a prototype in the Arab Emirates
A solar island demonstration plant is under construction in Ras al-Khaimah, covering an area of 5,000 square metres and with a capacity of 0.5 MW. When full-scale, these islands could measure 20 square kilometres and reach a capacity of 1,000 MW
Floating solar islands could provide a greater amount of energy than onshore ones, causing less environmental concerns. The latter was stated by Swiss-based Nolaris, the company that is developing a project for a floating concentrating solar island in Ras al-Khaimah, one of the United Arab Emirates.
The latter is designed as a circular area, surrounded by a tubular hollow ring that will have a 20-metre diameter and a circumference of several kilometres, when the prototype will be full-scale. The area inside the ring is covered by a huge membrane made of special plastic that is fixed to the frame in an airtight manner, supported by the air pressure that is trapped between the sheet and the surface of the water. Solar panels are placed on this membrane, which also supports the structures of the plant.
The prototype that is under construction in Ras al-Khaimah is a small-scale demonstration plant measuring about 5,000 square metres (the diameter is 80 metres), with a peak capacity of 0.5 MW. Its storage system can guarantee an average capacity of 100 kW around the clock and an annual production of 1.2 million kWh.
Each full-scale plant will cover an area of 20 square kilometres (with a diameter of around 5 km), and its capacity in areas close to the Equator will amount to 1,000 MW. Even a smaller island, measuring 6.4 square miles, could produce 1.5 billion kWh per year under the most favourable conditions.
Compared to onshore plants, solar islands not only avoid problems connected with land occupation, but also make it much easier to always find the right inclination angle to track sunlight. In fact, instead of having individual mirrors rotating to follow the apparent motion of the Sun, in this case the entire platform on which the mirrors are fixed is made to rotate.
Regarding energy transportation, as an alternative to onshore grid-connection, for plants that are further offshore, Nolaris plans to use steam electrolysis, producing hydrogen which will be conveyed onshore by means of special containers. Moreover, remote-controlled robots will take care of maintenance, with the primary task of keeping the mirrors clean.
(June 2010)
