Floating solar PV testbed at Tengeh Reservoir
In 2016, PUB and the Economic Development Board (EDB) launched a 1 megawatt-peak (MWp) floating solar photovoltaic (PV) testbed at Tengeh Reservoir to study the economic and technological feasibility of deploying large-scale floating solar PV systems on reservoirs. The testbed, managed by the Solar Energy Research Institute of Singapore (SERIS), comprised 10 different types of floating structures and PV modules constructed by nine different companies. This setup allowed PUB to compare the performance of the various PV installations (relative to each other and to PV systems on land).
The results were favourable and showed that floating solar PV systems performed 5 to 15 per cent better than a typical rooftop solar PV system in Singapore, primarily due to the cooler temperatures of the reservoir environment. Also, these solar panels, being out in the open waters, do not experience shading from any nearby buildings, which further enhances its ability to maximise solar energy generation. To date, there have been no observable changes in water quality and no significant impact on wildlife at the reservoir.
1MWp floating solar testbed on Tengeh Reservoir (Photo credit:SERIS)
PUB also carried out comprehensive engineering and environmental studies for a more thorough assessment of the impact of building a large-scale solar PV system on the reservoir. These studies included developing environmentally-sensitive system designs and construction processes. PUB also engaged nature groups on the scope of the environmental studies. The results showed that deploying a large-scale floating solar PV system would have minimal impact on the reservoir's water quality, flora and fauna, with appropriate planning and design.
Hence, PUB decided to build a large-scale 60MWp floating solar PV system on Tengeh Reservoir.
Sembcorp Tengeh Floating Solar Farm
In June 2019, PUB launched a Request for Proposal (RFP) to invite private sector companies to design, build, own and operate this large-scale floating solar PV system on Tengeh Reservoir, for 25 years. The RFP was awarded to Sembcorp Floating Solar Singapore in February 2020. Construction works started in August 2020 and the project was officially launched in July 2021.
Artist impression of the 60MWating solar farm on Tengeh Reservoir
At 60 MWp, the floating solar PV system on Tengeh Reservoir is one of the world's largest inland floating solar farms. It occupies 45 hectares (around 45 football fields in size), occupying one-third of the reservoir's surface. It comprises over 122,000 solar panels spread out across 10 floating solar panel islands. The clean energy generated is sufficient to power PUB's five local water treatment plants and the Marina Barrage, offsetting approximately 7% of PUB's annual energy needs. This is equivalent to powering about 16,000 four-room HDB flats and reducing our carbon emissions by about 32 kilotonnes per year, the same as taking 7,000 cars off Singapore's roads.
This floating solar farm will enable Singapore to be one of the few countries in the world to integrate green technology with water treatment, creating a fully green waterworks system.
Environmental Mitigation and Management
PUB has worked with Sembcorp to put in place a comprehensive Environmental Management and Mitigation Plan (EMMP) to minimise any impacts on the reservoir's biodiversity and water quality. The EMMP includes the monitoring and management of biodiversity, water quality, sediment quality and noise pollution before, during and post construction of the project.
Furthermore, the PV floats used are made of high-density polyethylene (HDPE) - a certified food-grade material, which is UV-resistant to prevent degradation from the intense sunlight exposure. Gaps between the solar panels allows for sufficient sunlight and airflow to enter the waters, supporting the aquatic ecosystem beneath. Additional aerators will also be deployed to maintain dissolved oxygen levels in the waters. The solar panels are designed with anti-reflective coating to minimise any glare or reflection. Two-thirds of the reservoir's surface have also been left untouched so that wildlife can continue to forage and hunt.
Water quality is monitored daily via online sensors, and through regular sampling & testing of reservoir water. Raw water from the reservoir will continue to be treated at PUB's water treatment plants before being conveyed to customers' taps.
Floating solar PV systems at Bedok and Lower Seletar Reservoirs
In 2018, PUB called a tender to conduct engineering studies for the deployment of two smaller floating solar PV systems at Bedok and Lower Seletar Reservoirs. Following up from the successful studies, PUB awarded a contract to local engineering firm BBR Greentech Pte Ltd to build the systems in 2019. BBR Greentech was one of the companies that had participated in the 1 MWp floating solar PV testbed on Tengeh Reservoir.
Both 1.5 MWp floating solar PV systems are deployed on the reservoir surfaces adjacent to Bedok Pumping Station and the Lower Seletar Pumping Station, taking up 2% of Bedok Reservoir's and 0.5% of Lower Seletar Reservoir's surface areas. These two floating solar PV systems can collectively generate enough energy to power about 800 four-room HDB flats and reduce PUB's carbon emissions by around 1.5 kilotonnes annually – or the same as taking 300 cars off Singapore's roads.
1.5 MWp floating solar PV system at Lower Seletar Reservoir
Other reservoirs considered for floating solar deployment
PUB is also conducting an Environmental Impact Assessment (EIA) on the feasibility of deploying a 6.7MWp floating solar PV system at Upper Peirce Reservoir. This includes consulting the relevant public agencies and nature groups on the new floating solar deployment. More details will be shared when ready.
With the experiences gained from these existing floating solar projects, PUB will continue to explore the solar deployment potential of other reservoirs in Singapore.
Learn more about our Rooftop Solar Systems here.