Figure 1 Floating solar panels on the surface of the Hapcheon Dam in South Korea. The project can generate enough to power 20,000 homes, according to Hanwha Solutions. Source: Bloomberg Photographer: SeongJoon Cho/Bloomberg
Solar floating photovoltaic (FPV) or Flotovoltaic technology is an innovative deployment of traditional solar photovoltaic (PV) systems where PV modules are mounted on floats and anchored on water bodies such as ponds, reservoirs, lakes, and even the open sea.1 The potential application of FPV technology is huge: a recent study found that FPV has the potential to generate 9,434 TWh of electricity per year by covering 30 per cent of the surface of 115,000 global reservoirs.2 In this study, Australia was ranked 8th of all nations in terms of suitability to generate electricity via FPV.
While FPVs have been in the market since 2007, it is only recently that the uptake has grown, especially in the Southeast Asian market. The scalability of FPV installations makes them a versatile option for countries seeking to expand their renewable energy capacity while addressing land scarcity and water conservation concerns. The table below highlights the key advantages FPV has over traditional (ground-mounted) PV.
Comparison of FPV and PV
| Characteristic | Ground-mounted photovoltaics | Floating photovoltaics |
| Cost | High land cost.
Cost of PV modules are decreasing. |
More expensive due to need for floats, anchoring, mooring and plant design. However, costs may be offset by a better performance ratio.
Installing FPV on existing reservoirs preserves land for other uses and as reservoirs are often located close to existing grid systems, this may result in additional savings.
|
| Soiling | Amount of soiling depends on surrounding landscape. In 2018, soiling reduced power production by 3 to 4 per cent and cost revenue loss of EUR 3 – 5 billion.3 | Less likely to experience soiling. In some circumstances, water on site may be used to clean panels. |
| Shading | Amount of shading depends on surrounding landscape. | Limited shading and higher sun exposure. |
In 2016, Singapore launched the 1-megawatt peak (MWp) FPV testbed at Tengeh Reservoir to study the economic and technological feasibility of deploying large-scale FPV systems.4 They found FPV performed 5 to 15 per cent better than traditional solar PV systems and attributed it to the cooling effect of the water on the panels.5 The optimal temperature for solar panel performance is 25°C and variances in temperature affects overall energy production. Given the high temperatures experienced during Australian summers, there is clear benefit of installing FPV to optimise energy production and minimise water evaporation.
Interestingly, researchers at the Tengeh Reservoir concluded that there was no observable change in water quality or significant impact on wildlife resulting from FPV.6 That said, they noted that further research is required to understand the long-term impacts of FPV on water quality and organisms living in associated bodies of water.
Outlook for FPV in Australia
The outlook for FPV is generally positive, despite potential vulnerability due to climate variability as low radiation, high temperatures or clouds can result in reduced PV power output in the future.[7]
Two key uses of FPVs in Australia are on farm dams and in connection with Pumped Hydrogen Energy Storage (PHES) Systems.
Farm dams
To date, the adoption of FPV in Australia has been limited. This may be attributed to the availability of land to install ground-mounted PVs, as well as the fact that ground-mounted PV technologies are more developed. However, there are emerging issues with competing land uses between ground-mounted PVs and agriculture. FPV provides a more efficient alternative to ground-mounted PVs and frees up agricultural land. By contrast, oversized farm dams ((larger than 0.01 km2) are ideal sites for the installation of FPV and will rarely conflict with existing land use.8
More than 3000 reservoirs in Australia have been identified as suitable for FPVs. Accordingly, developers and investors may be selective by developing FPV projects on farms which are located close to existing grid infrastructure, thus minimising project costs.9
FPVs are also relatively less expensive to install on farm dams compared to other water bodies. The minimal water movements allow for a simpler anchoring design that is adapted to suit Australian weather conditions, and the panels can be designed to rest on the floor of the dam during periods of drought, and rise and float in instances of flooding.
Complementarity of FPV and PHES Systems
Sites at which two large farm dams are situated at least 200 – 300 metres altitude difference from each other have been identified as ideal sites for PHES projects.10 By integrating PHES and FPV systems, investors can leverage the strengths of both technologies to create a highly efficient and sustainable energy ecosystem. The combined setup ensures a continuous and stable energy supply, mitigating the intermittent nature of solar power.
Given PHES systems require an energy input (ideally from a renewable source), installing FPV on the site maximises the utilisation of the water body (for both energy generation and storage) and the reduction in water evaporation can boost hydropower generation. Further, a hybrid system enables a more optimal use of the transmission network and reduces the need for fossil fuel-based backup power. As technological advancements, falling costs, and supportive policies continue to converge, hybrid energy solutions will continue to play a pivotal role in creating a stable and resilient national energy market.
The Hamilton Locke team advises across the energy project life cycle – from project development, grid connection, financing, and construction, including the buying and selling of development and operating projects. For more information, please contact Matt Baumgurtel.
1Kinstantin Ilgen et al, ‘The impact of floating photovoltaic power plants on lake water temperature and stratification’ (2023) 13(7932) Scientific Reports https://doi.org/10.1038/s41598-023-34751-2
2Yubin Jin et al, ‘Energy production and water savings from floating solar photovoltaics on global reservoirs’ (2023) (6) Nature Sustainability 865-874. https://doi.org/10.1038/s41893-023-01089-6
3Essak, L., & Ghosh, A, ‘Floating Photovoltaics: A Review’ (2022) 4(3) Clean Technologies 752–769. https://doi.org/10.3390/cleantechnol4030046
4‘Floating Solar Systems’ Singapore’s National Water Agency (Web Page) https://www.pub.gov.sg/sustainability/solar/floatingsystems.
5Ibid.
6Ibid.
7Yubin Jin et al, ‘Energy production and water savings from floating solar photovoltaics on global reservoirs’ (2023) (6) Nature Sustainability 865-874. https://doi.org/10.1038/s41893-023-01089-6
8Yubin Jin et al, ‘Energy production and water savings from floating solar photovoltaics on global reservoirs’ (2023) (6) Nature Sustainability 865-874. https://doi.org/10.1038/s41893-023-01089-6
9Ibid.
10‘ANU finds 22,000 potential pumped hydro sites in Australia’ Australian National University (Webpage, 21 September 2017) https://www.anu.edu.au/news/all-news/anu-finds-22000-potential-pumped-hydro-sites-in-australia
