Solar photovoltaic systems need clear skies and abundant sunshine to be productive. As long as these two conditions are met, the foundation on which the array is mounted does not matter. Since wind turbines -more complex machines than solar panels- have already been mounted on floating platforms, there is no reason why we can’t deploy floating solar power arrays.
In New South Wales, the Lismore City Council have established an ambitious Renewable Energy Master Plan, with the goal of supplying 100% of the city’s electricity from renewable sources by 2023. The East Lismore Sewage Treatment plant is among their buildings with the highest energy consumption, and they were considering solar power but lacked the land required to deploy a photovoltaic array. Therefore, they decided to test the concept of floating solar power above their overflow pond.
The first stage of the project uses 280 solar panels with a total installed capacity of 100 kW, and is expected to produce 180,000 kWh annually, enough to meet 12% of the facility’s electricity demand. The completed installation will be over 8 times larger, allowing the sewage treatment plant to become 100% solar powered.
Solar panels operate more efficiently when their temperature is reduced, and proximity to the water will provide a cooling effect, thus increasing the energy output of each panel. In addition, the installation will have a longer service life thanks to reduced-temperature operation. The overflow pond will also benefit from the presence of solar panels: since they block a portion of the sunshine reaching the pond, they will reduce evaporation and will help control algae growth.
The solar panels will be mounted close to the water level, but the array can be lifted up to 12 metres to protect it from storms. In addition, the floating racking system will be anchored to the bottom of the pond. Although solar panels have minimal maintenance requirements, their surface must be kept clean to guarantee optimal performance. The floating array will be equipped with walkways to simplify maintenance tasks.
Australia is surrounded by the ocean on all sides, and the largest population centers are located close to the shore. The concept of floating solar farms could be deployed at a larger scale to take advantage of this, and the proximity with population centers will minimise transmission losses.
Another advantage of floating solar power is that the water is free from obstacles that can cast shadows on the array. Just like floating wind turbines are more productive because wind flows more freely, floating solar arrays can achieve a higher productivity per panel because the sky is clear. Although rooftop solar array are also cost-effective, they are occasionally affected by the shadows of trees and other buildings, and larger terrain features like mountains and hills can also block several hours of sunshine each day.