| Hydropower & other renewables
surrounded by circular floatation collars used by the aquaculture industry. Modular design means each ring can provide up to 0.7 MWp and mats of rings can be manufactured on a beach then tethered together to form a stable unit of up to many megawatts before being towed into position and moored permanently. The flexibility of the membrane means the unit behaves like oil on troubled water, preventing breaking of waves even in hurricane conditions. Moorings can be designed to tackle many metres variation in reservoir level, or even the occasional resting of the membranes on the lakebed. The horizontal aspect of the solar panels makes this design best suited to tropical and semi-tropical reservoirs and here there are additional benefits. Since the back of the panels are in full contact with the thin membrane the conductive cooling of the underlying water is far more effective than convective air cooling of pontoon mounted alternatives. Researchers [2] have documented this effect as resulting in higher voltage which gives better energy yield than the same panel mounted on pontoons, land or rooftops. Secondly, the flat design almost eliminates the wind drag that otherwise would occur with tilted panels, enabling deployment also at sea or in big lakes. In contrast to floating PV designs based on floats or
pontoons there is little wind resistance, and the latest pilot is designed to test the concept in exposed marine waters where pontoons would soon get destroyed. The circular polyethylene floatation rings developed for the fish farming industry are conveniently manufactured at site. These buoyancy rings and the large impermeable membrane provides an installation surface that also protects the PV panels from the moist corrosive saltwater environment. The polymer membranes also effectively stop evaporation of valuable fresh water from reservoirs, or conversely catch rainwater to provide fresh
www.waterpowermagazine.com | January 2024 | 29
water. Surplus water on the membrane is evacuated using small bilge pumps. The ability to flood the surface of the system with clean water and wash out any airborne pollutants makes it possible to obtain a low level of soiling such as bird droppings. The special combination of commonly available
materials results in costs on a par with ground mounted PV plants. Each membrane can be packed into a single container and reduces transport cost to remote locations. Horizontal panels are optimal for locations near the equator such as in South America, Africa and the Middle East, Asia and the Indo- Pacific, but much interest has also been generated by Mediterranean countries. A new pilot will be constructed in Spain in January 2024.
Favoured location Locations where there is no available land for ground
mounted PV are favoured and lush vegetation, rainforest, farmland, and recreational areas can
Below: the completed four rings at Banja Dam
Above: Ocean Sun 2MWp during construction. The last ring can be seen on the far bank of Banja reservoir in Albania, 2022
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37
