by Masud Karim:

BANGLADESH grapples with the dual challenges of climate change and high cost of fossil fuel against the dwindling foreign currency reserves. Renewable energy sources can in such a situation be an alternative. Solar power has emerged as one of the most widely adopted forms of clean energy. However, conventional ground-mounted solar installations typically demand significant land resources, already scarce. Moreover, the land acquisition process is often complex and costly, potentially leading to conflicts with agriculture, forestry, and urban development. Floating solar plants, also known as floating photovoltaic systems, present an innovative solution to the challenges by leveraging unused water surfaces for clean energy generation.

Floating solar plants

FLOATING solar plants involve the installation of solar photovoltaic panels on platforms that float on water bodies such as lakes, reservoirs, ponds and coastal areas. These systems are anchored to the bottom of the water body or moored to its edges to ensure stability. The electricity generated is transmitted to the grid or storage systems through underwater cables. Unlike traditional solar farms, floating photovoltaic systems maximise the utility of under-used aquatic spaces, offering a sustainable and innovative way to generate energy.

Advantages

Land use optimisation: Floating solar plants use water surfaces, avoiding the need for costly land acquisition and mitigating conflicts with agriculture, housing and other land uses. This is particularly advantageous for land-scarce regions such as Bangladesh and urban areas.

Efficiency improvement: The cooling effect of water reduces solar panel temperature, enhancing energy conversion efficiency, minimising thermal stress and prolonging panel lifespan for consistent energy output.

Albedo effect: Water bodies enhance the efficiency of floating solar panels through their reflective properties, increasing sunlight exposure to the panels. This boosts photon absorption, amplifying energy yield and optimising solar energy generation.

Water conservation: Floating solar panels conserve water by reducing evaporation, especially in arid regions facing water scarcity. Their shading effect curbs water loss and inhibits algae growth, improving water quality and preserving vital resources.

Environmental benefits: Floating solar systems cut greenhouse gas emissions by replacing fossil fuels with renewable energy and improve water quality by limiting sunlight, reducing algal blooms.

Low impact on aquatic life: Preliminary studies suggest that floating solar installations have less impact on aquatic life than other structures. A careful design and placement ensure minimal disruption, promoting coexistence with ecosystems.

Reduced transmission losses: Floating solar systems installed on reservoirs near hydropower plants or urban centres reduce transmission losses by being closer to energy demand hubs, enhancing efficiency and reliability.

Scalability: Floating solar installations are modular and scalable, making them suitable for both small communities and large industrial needs.

Lower levelised cost of energy: The lower levelised cost of energy, the average lifetime cost of electricity generation, was 56 per cent lower for solar photovoltaic systems in 2023 compared with fossil fuels, underscoring its economic and sustainable advantages.

Challenges

High initial investment: Floating solar plants require specialised materials such as corrosion-resistant components and underwater cabling and increasing costs, but their investment remains lower than fossil fuel power generation.

Technical maintenance: The aquatic environment poses challenges like biofouling or the accumulation of algae and microorganisms, sediment buildup and water-induced wear, making regular maintenance essential for efficiency and durability.

Environmental concerns: Despite their benefits, floating solar plants can disrupt ecosystems by blocking sunlight, affecting underwater flora and fauna, and altering ecological balance.

Weather vulnerability: Floating solar plants are vulnerable to storms, winds and floods, requiring robust anchoring and mooring systems to mitigate potential damage.

Regulatory hurdles: Installing floating solar plants often involves navigating complex regulations on water use, environmental impact and grid integration.

Global case studies

SEVERAL countries have embraced floating solar technology, demonstrating its potential for widespread adoption.

China: Home to some of the world’s largest floating solar plants, China has used former coal mining sites and reservoirs to generate renewable energy. The Anhui province hosts a 150MW floating solar farm, showcasing the scalability of the technology.

Japan: With limited land for renewable energy projects, Japan has adopted floating solar plants on reservoirs and water treatment facilities. The Yamakura dam hosts a 13.7MW floating solar plant.

India: India has launched ambitious plans for floating solar plants to reduce dependency on fossil fuels. The Kayamkulam project in Kerala and the Ramagundam project in Telangana are notable examples.

The Netherlands: Known for its water management expertise, the Netherlands has integrated floating solar systems with existing water infrastructure such as floodplains and canals.

Some of the South Asian countries including Bangladesh are in the process of implementing the following projects.

Bangladesh: Rural Power Company Ltd is implementing the 200MW floating solar photovoltaic power plant project in Mollahat, Bagerhat in two phases (100MW each). This on-grid solar power plant will be integrated with cultured fish farming, creating a sustainable energy and aquaculture solution.

India: The 500MW West Bengal floating solar project, supported by the Asian Development Bank, aims to boost renewable energy at the Bakreswar dam reservoir while supporting drinking water supply and the Bakreswar thermal power station.

Pakistan: The World Bank-funded floating solar in Pakistan project includes two 150MW sites — Ghazi Barrage Headpond at the Tarbela hydropower reservoir and Ghazi Barotha Forebay, enhancing hydropower efficiency and boosting renewable energy generation

Prospects

THE future of floating solar plants in Bangladesh is promising, driven by advancements in technology and growing awareness of climate change, with cost-efficient panels on the market and strong commitment from the government on the renewable energy. The government or private sector investors might consider the following three water bodies.

Kaptai Lake, Bangladesh’s largest man-made freshwater lake, spans 688 square kilometres in Rangamati. Created in 1961 by damming the River Karnaphuli for the Karnaphuli hydroelectric project, it supports power generation, irrigation, fisheries and transport. With depth reaching 53 metres, using 10 per cent of its area could generate 6,200MW, requiring a $6.2 billion investment (2023 prices), showcasing its renewable energy potential.

Hakaluki Haor, one of Bangladesh’s largest freshwater wetlands, spans 181.15 square kilometres across Moulvibazar and Sylhet. Its depth varies from 1.5–2 metres in the dry season to 6–7 metres during the monsoon season. Harnessing 10 per cent of its area could generate 1,600MW of renewable energy, requiring a $1.6 billion investment (2023 prices), highlighting its ecological and economic potential.

Chalan Beel, the largest wetland in Bangladesh, spans 368 square kilometres across Pabna, Natore, and Sirajganj during the monsoon season. Its depth ranges from 1–2 metres in the dry season to 4–5 metres during the monsoon season. Using 10 per cent of its surface could generate 3,300MW of electricity, requiring a $3.3 billion investment (2023 prices), highlighting its renewable energy potential alongside its ecological and socio-economic significance.

Floating solar plants highlight the innovative potential of renewable energy in tackling global challenges. By using under-used water surfaces, the systems offer a sustainable, efficient and eco-friendly approach to meeting energy demands. While challenges such as high initial costs and environmental concerns require attention, ongoing research, supportive policies and technological progress can unlock their full potential. Floating solar plants are poised to become a crucial part of its energy landscape.

Dr Masud Karim is a Toronto-based environmental specialist.