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Floating Solar Photovoltaic Systems on Reservoirs

Solution Overview

The Water Supplies Department (WSD) has pioneered floating photovoltaic (FPV) technology on Hong Kong's reservoirs, beginning with two 100 kW pilot systems installed at Shek Pik Reservoir and Plover Cove Reservoir in 2017.[1][2][3] This approach explores electricity generation potential from reservoir surfaces while addressing both renewable energy needs and water resource management.[7][8][9] The initiative represents Hong Kong's first deployment of floating solar technology, with the Shek Pik installation commissioned in February 2017 marking the city's inaugural FPV system.[3][22]

Technical Components

The Shek Pik Reservoir system comprises 352 solar PV panels installed over approximately 1,100m² of water surface, representing about 0.1% of the total reservoir area.[3][10] The system converts sunlight into electricity supplied directly to pumps at the nearby Shek Pik Valve Tower, designed for 100kW output power.[3][12] The Plover Cove installation features over 350 monocrystalline PV panels mounted on a high-density polyethylene floating platform, configured as a grid-connected renewable energy system.[6][30] Associated electrical and mechanical installations include direct current to alternating current inverters and isolation transformers.[6][32] The cooling effect from reservoir water facilitates system efficiency, with the cool and open reservoir environment enhancing electricity generation efficiency by around 20% compared to roof or ground-mounted installations.[3][19][40]

Implementation Details

WSD completed installation of both pilot FPV systems in 2017, with the Shek Pik system commissioned in February 2017 and the Plover Cove system following in October 2017.[1][5][22][23] Each 100 kWp system was designed to generate approximately 120,000 kWh of electricity annually.[1][4][10] The total capital cost for the Shek Pik 100 kWp system reached approximately HK$1.5 million, equivalent to HK$15/Wp.[15] Cost breakdown included PV modules (HK$400,000), inverters (HK$150,000), floating structure (HK$500,000), mooring and anchoring system (HK$200,000), cabling and electrical works (HK$150,000), and installation and commissioning (HK$100,000).[16] A third pilot system was successfully installed at Tai Lam Chung Reservoir in April 2022 to supply electricity to the nearby air compressor house.[9] These pilot projects aimed to test FPV system performance and reliability in Hong Kong's environment.[27] Implementation faced constraints as most reservoirs are located in protected scenic areas of country parks, requiring careful consideration of ecological, environmental, and landscape impacts.[2][33] Of Hong Kong's 17 impounding reservoirs, not all are feasible for FPV installation over their water surfaces.[1]

Benefits and Impacts

The two 100 kW systems each generate up to 120,000 kWh of electricity annually, equivalent to the annual consumption of 36 households per system.[2][21][29] Combined annual electricity generation from both pilot systems totals approximately 240,000 kWh, equivalent to powering about 60 households.[5] The installations achieve a total carbon emissions reduction of 84 tonnes annually.[2][3][29] The Shek Pik system saves the pumping station's electricity expenses by 25%.[11] Green electricity generated powers water treatment facilities including air compressors and pumping plants.[6][31] Beyond energy generation, the PV systems covering reservoir areas help reduce water evaporation and improve water quality by suppressing algae growth.[3][18][41] The floating installations protect water resources while controlling algae development.[41]

Climate Adaptation Relevance

This technology addresses climate adaptation through dual benefits of renewable energy generation and water resource protection. The systems reduce carbon emissions while simultaneously mitigating water evaporation—a critical concern as climate change intensifies drought conditions and water scarcity risks. By generating clean electricity at the point of water infrastructure, the approach enhances resilience of essential water supply operations against climate-related energy disruptions.

Business Analysis

Building on pilot project success, WSD planned to install larger floating solar energy generation systems with generating capacity of 5-10 MW each at various reservoirs, including Plover Cove Reservoir, Shek Pik Reservoir, and Tai Lam Chung Reservoir.[2] The department embarked on a study for installing a floating solar energy generation system with generating capacity exceeding 100 MW at Plover Cove Reservoir.[2][17] A 5 MW floating solar farm at Plover Cove Reservoir was expected to generate power equivalent to 1,800 household requirements.[7] WSD planned to launch a tender for this 5 MW FPV project at Plover Cove Reservoir in 2018, representing Hong Kong's first large-scale FPV project and a major advancement in renewable energy development.[28] The larger-scale project was estimated to generate more than 100 million kWh of electricity annually, meeting approximately 0.2% of Hong Kong's total electricity demand.[39] The HK$15/Wp capital cost structure for the pilot systems established baseline economics for scaling considerations.[15]

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