Sembcorp, PUB open one of world's largest floating solar farms on Tengeh Reservoir

SEMBCORP Floating Solar Singapore, a wholly-owned subsidiary of Sembcorp Industries, and Singapore's national water agency PUB on Wednesday announced the official opening of the Sembcorp Tengeh Floating Solar Farm at the Tengeh Reservoir.

With this, Singapore is one of the few countries in the world to have a waterworks system that is fully solar-powered. The farm will also contribute to Singapore's goal of quadrupling solar energy deployment by 2025.

The launch ceremony on Wednesday was officiated by Prime Minister Lee Hsien Loong; Minister for Sustainability and the Environment Grace Fu, and the Permanent Secretary of the Ministry of Sustainability and the Environment Albert Chua, as well as top executives from Sembcorp and PUB.

During his speech at the opening of the Sembcorp Tengeh Floating Solar Farm, Mr Lee noted that Singapore is now one of the most solar-dense cities in the world, having grown its solar capacity by more than seven times since 2015. Singapore also plans to install at least two giga-watt peak of solar photovoltaic capacity by 2030.

"Innovations such as floating solar farms will help us overcome our physical constraints," said Mr Lee. "I hope this project will give our solar and renewable energy industry a boost, and pave the way for more such facilities to be built here and in the region.

"This will take us one big step towards environmental sustainability, as we transition into a low-carbon future."

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The 60 megawatt-peak solar photovoltaic farm has some 122,000 solar panels spanning across 45 hectares, or the equivalent of about 45 football fields. This makes it one of the world's largest inland floating solar photovoltaic farms.

Both PUB and Sembcorp first began exploring the possibility of floating solar photovoltaics in Singapore back in 2011.

After a "decade-long journey" that involved engineering and environment feasibility studies and extensive comparisons between different technologies and designs, solar panels in the Sembcorp Tengeh Floating Solar Farm are expected to perform 5 to 15 per cent better than conventional rooftop solar panels, according to a test-bed at the reservoir that was constructed in 2016.

The electricity generated from the solar farm will be sufficient to power Singapore's five local water treatment plants, offsetting about 7 per cent of PUB's annual energy needs. The farm will also reduce carbon emissions by about 32 kilotonnes every year, or the same as taking 7,000 cars off the road.

"The Sembcorp Tengeh Floating Solar Farm is a crown jewel in our portfolio, and a showcase for Singapore," said Sembcorp chief executive Wong Kim Yin.

However, both companies were quick to stress that the completion of the project did not come easy.

The Covid-19 pandemic had resulted in a labour crunch when travel restrictions and social distancing measures kicked in. According to the two companies, these made it harder for them to "speed up" the construction process.

In his speech, Sembcorp chief executive Wong Kim Yin said the Sembcorp team "redesigned work teams and shifts" to manage restrictions that were in place and came up with new ideas to make up for lost time and boost efficiency.

The team also overcame supply chain and logistics issues that were brought about by the pandemic, added Mr Wong.

PUB's main concern with deploying solar panels on reservoirs was the potential impact on the surrounding environment, biodiversity and water quality.

The farm was hence carefully designed to minimise any such impact on the reservoir's water quality, flora and fauna through sufficient gaps between the panels to improve airflow and allow sufficient sunlight to reach aquatic life. Additional aerators were also put in place to maintain oxygen levels in the reservoir.

Floats deployed in the farm are also made using high-density polyethylene (HDPE) - a certified food-grade material that is recyclable, UV-resistant and corrosion resistant.

Although water could potentially cause corrosion to the systems of the farm, each component appeared to have been carefully designed and selected in order to minimise environmental and water quality impact.

For instance, the solar panels in the farm use double-glass photovoltaic modules instead of the single-glass variant commonly used for rooftop installations to enhance durability in a wet and humid environment. The panels are also strategically designed to prevent degradation from intense sunlight exposure.

Jen Tan, Sembcorp's head of integrated solutions for Singapore and South-east Asia said the solar panels in the farm have a planned annual degradation rate of 3 per cent for the first year. For every year thereafter, the panels are expected to degrade by about 0.5 per cent annually.

"The panels have gone through extreme testing, and (they're) able to last that long. For the projects that we've deployed over the past couple of years, we do not see major issues," said Ms Tan.

PUB and Sembcorp also said that drones will be used for regular operation and maintenance checks, which helps to cut manual inspection costs by 30 per cent.

The farm will also deploy advanced drone electroluminescence imaging technology which captures signals emitted by photovoltaic modules to accurately and rapidly pinpoint defects in the system from the manufacturing to installation stage.

Both PUB and Sembcorp also said they will regularly monitor biodiversity and water quality at the reservoir.