Amid the pressing need for a carbon-neutral future, the quest for clean and sustainable energy solutions has spurred a wave of technological advancements across the globe. At the forefront of this movement is floating solar, a marriage of two abundant and renewable resources – water and sunlight. While traditionally celebrated for their individual contributions to the clean energy revolution, hydropower and solar energy are now combining their strengths in a synergistic partnership that defies geographical boundaries.

As floating solar installations gain momentum, they demonstrate their versatility and adaptability to various landscapes and climates worldwide. From bustling metropolitan centres to remote rural communities, the allure of harnessing the dual power of water and sun proves irresistible. In this feature, we explore successful case studies from different continents and look at the potential for this growing partnership.

Potential in Southeast Asia

For nations blessed with abundant solar resources but faced with limited land space, the concept of floating PV, or FPV, has emerged as a promising clean energy solution. Recently, researchers from the National Renewable Energy Laboratory (NREL), supported by the laboratory`s partnership with the United States Agency for International Development`s (USAID) Regional Development Mission for Asia, conducted a groundbreaking evaluation of FPV potential in the Association of Southeast Asian Nations (ASEAN).

This landmark report, titled “Enabling Floating Solar Photovoltaic (FPV) Deployment: FPV Technical Potential Assessment for Southeast Asia,” presents a comprehensive estimation of FPV`s technical potential across the ten ASEAN member countries. The study is further bolstered by an FPV data set, accessible to the public through the USAID-NREL Partnership`s Renewable Energy (RE) Data Explorer tool.

Although traditional renewable energy sources like solar arrays and wind farms are effective for energy generation, they often encounter challenges related to land use. In contrast, floating photovoltaic (FPV) arrays offer a unique solution by being installed on water bodies such as lakes, reservoirs, or water treatment ponds. This approach not only eliminates land use concerns but also optimizes otherwise unused water surfaces for energy production. In cases where hydropower infrastructure is already established or planned, FPV arrays can complement these facilities, mitigating concerns about electricity reliability during droughts or water scarcity.

This holds particular significance for Southeast Asia, a region with substantial existing hydropower infrastructure but occasional energy security concerns during periods of water scarcity. FPV can work synergistically with hydropower, providing additional energy generation support during low reservoir levels or droughts, thus ensuring grid stability.

“While we can`t generalize about Southeast Asia as a whole, one thing that is basically universally true of the region is that it has an established network of hydropower generation sites. FPV can support these sources as water levels fluctuate to ensure grid stability,” said Evan Rosenlieb, a geospatial data scientist at NREL who performed the resource and technical potential analysis for this project.

Moreover, much of Southeast Asia is covered by rainforest ecosystems, making it crucial to explore renewable energy solutions that don`t involve deforestation. FPV`s installation on water surfaces presents an environmentally friendly way to increase renewable energy capacity without encroaching on forests and their ecological significance.

Moreover, in Southeast Asia, there is a growing interest in exploring water-based solutions, one of which is aquaculture—a farming method that involves raising aquatic creatures like fish, crustaceans, and other species in controlled water environments. The presence of aquaculture sites offers distinctive opportunities and advantages for the deployment of floating photovoltaic (FPV) systems.

“Along with its other co-benefits, FPV can play an important role in bolstering food security in Southeast Asia through incorporation with the region`s fast-growing aquaculture industry,” said Prateek Joshi, NREL energy engineer and lead author of the report.

“This emerging combination of aquaculture and photovoltaics, commonly referred to as AquaPV, can allow countries to colocate energy and food production on existing natural or artificially created water bodies while minimizing the overall environmental impact of both sectors,” Joshi said.

Renewable energy goals

In Southeast Asia, the pursuit of ambitious renewable energy goals has led countries to seek innovative solutions to meet their targets. Floating photovoltaic (FPV) technology has emerged as a promising avenue to turn these aspirations into reality. As a collective effort, ASEAN nations have set a commendable target of achieving 35% of installed power capacity from renewable sources by 2025. This ambitious objective has fueled their interest in exploring bold and creative approaches, including the development of FPV systems.

“FPV is an option that can allow many of these countries to take advantage of high-quality solar resources to combat challenges such as land availability or rugged geographies that can make siting traditional renewable energy sources difficult,” said Sika Gadzanku, the NREL energy technology and policy researcher who led the development of this analysis. “They also offer resilience opportunities in regions that use a lot of hydropower but are facing droughts and significant changes in rainfall patterns.”

“Southeast Asia leads FPV deployment, and Thailand is emerging as a major player in this space. Our FPV work has really been demand-driven—several country partners and developers expressed their interest in FPV and in turn, we embarked on our first Southeast Asia-specific FPV analysis four years ago,” Gadzanku said.

Gadzanku has rapidly emerged as an expert in the field of floating photovoltaic (FPV) research and development, with a remarkable track record over the past four years. Her comprehensive investigations into FPV development in Southeast Asia include a detailed report in 2021, focusing on barriers to FPV deployment, and an insightful analysis in 2022, exploring the operational benefits of FPV-hydropower hybrid systems.

Recently, from June 13 to 16, 2023, Gadzanku, accompanied by Sadie Cox (USAID-NREL Partnership Portfolio Manager) and Derina Man (Advanced Energy Partnership for Asia program lead), journeyed to Manila, Philippines, to participate in the Asia Clean Energy Forum.

During this event, Gadzanku actively contributed to two sessions. On June 13, she presented as part of Session 4.1, shedding light on the “Current Status and Future Trends in Renewable Energy in Asia and the Pacific.” Her presentation centred around the findings from the technical potential assessment of FPV in the region. On June 14, she participated in the “Spotlight Session: Digital Technology as a Driver of Decarbonization,” where she highlighted the unique geospatial capabilities of the RE Data Explorer tool and the invaluable FPV data set accessible through it.

Building upon the groundwork laid by previous FPV studies, Gadzanku and her team from NREL utilized existing data on water bodies, infrastructure, and energy resources to identify areas with the highest potential for FPV development. Their meticulous analysis revealed that all ASEAN countries possess significant potential for FPV energy generation.

Recognizing the importance of data in making informed decisions during FPV project development, the USAID and NREL teams have made this critical technical potential data available through the RE Data Explorer tool. This valuable resource will aid developers, policymakers, and other stakeholders in the region as they embark on FPV projects.

Chatchai Mawong, assistant governor of power plant engineering and construction at the Electricity Generating Authority of Thailand, emphasized the significance of accurate and detailed site location data, given the geographic variations in Southeast Asian countries. It plays a vital role in determining project feasibility, technology selection, project costs, and environmental sustainability.

This newly added FPV data set to the RE Data Explorer marks a milestone, granting Southeast Asian stakeholders access to more comprehensive analyses to assess renewable energy generation. Gadzanku expressed her excitement over the potential of this data to inspire discussions and inform decisions regarding FPV`s role in the region. She acknowledged that this achievement would not have been possible without the collective efforts of previous FPV studies and the continuous development of the RE Data Explorer tool.

With its public accessibility, the data becomes a valuable resource for a wide range of stakeholders, including energy planners, modellers, developers, and researchers. It will undoubtedly bolster detailed FPV research activities, modelling, and analysis efforts across the region.

Large projects commissioned

A number of countries are making waves with their groundbreaking floating solar projects. At the end of June, China successfully launched the Kela photovoltaic (PV) power station – the world`s largest hybrid solar-hydropower plant. Constructed by Yalong River Hydropower Development, also known as Yalong Hydro, the Kela station aims to expand the renewable energy capacity of the Yalong River basin and contribute significantly to China`s sustainable energy goals. The plant commenced full-scale operations on 28 June, marking a groundbreaking achievement in the country`s commitment to achieving net-zero emissions.

Conceptualized by the Design and Research Institute of Power China Chengdu in 2016, the Kela solar-hydropower project boasts an impressive installed capacity of 1GW and is projected to generate 2GWh annually. By harnessing the power of the sun and the river, this initiative is estimated to reduce carbon dioxide emissions by 1.6 million tonnes per year. Furthermore, the project`s overall planned capacity is anticipated to reach an impressive 3GW, serving as a pivotal force in China`s ambitious sustainability endeavours.

As the inaugural phase of the Lianghekou hydropower plant, the commencement of operations at the Kela station represents the beginning of the Yalong River basin`s transformation into a prominent hub for clean energy in China. This development will play a pivotal role in supporting the nation`s net-zero commitments and forging a greener, more sustainable future.

“China is leading the way in renewable energy. We congratulate Yalong Hydro for this deployment of the world’s largest hybrid solar-hydropower plant,” said Eddie Rich, the International Hydropower Association’s Chief Executive Officer. “Hybrid PVs have a huge capacity to contribute to meeting global energy demands while making use of hydropower’s flexibility and storage capabilities. This is a major step in the right direction for meeting net-zero targets.”

The significance of projects like the Kela station, as emphasized in the 2023 World Hydropower Outlook, lies in their ability to exemplify the critical role that sustainable hydropower plays in the energy transition. By combining the flexibility and storage capabilities of hydropower with the intermittent nature of solar energy, these hybrid projects ensure a round-the-clock electricity supply, guaranteeing a reliable, safe, and low-carbon power system. Moreover, in addition to enhancing grid flexibility, the Kela station will support the development of various local industries such as agriculture, tourism, and transportation, aligning with the key themes outlined in the World Hydropower Outlook.

He Shengming, Deputy General Manager of Yalong Hydro, expressed his delight at the inauguration of the Kela power station, emphasizing the positive impact it would have on Chengdu citizens. He remarked, “We are delighted to see the Kela power station begin producing electricity for Chengdu citizens who suffered from power shortages during last summer`s heatwave. The Kela PV station connected into the Lianghekou hydropower plant as a virtual generator breaks ground for the clean energy base building in China.”

It`s not just China that is making inroads. Also in late June, South America`s largest floating solar project was launched at Colombia`s Urrá Dam. The project, developed by Noria Energy, encompasses a 1.5MW solar power system floating on the reservoir. More details on this project can be found in our feature focusing on South America on p12.

Across the pond in France, EDF Group has inaugurated the Lazer floating solar power plant in the Hautes-Alpes, the first for its EDF Renewables subsidiary in France and the first to combine photovoltaic and hydroelectric production on the same site. The installation effectively doubles the renewable electricity production capacity of the existing hydroelectric site.

With over 50,000 solar panels, the Lazer floating solar power plant boasts an installed capacity of 20MWp. This output is expected to meet the annual electricity consumption needs of approximately 12,500 people. The project aligns with France`s goals to achieve 100GW of solar capacity by 2050.

The primary aim of the solar power plant is to complement the dam`s operations, particularly during the summer months when water from Lazer Lake is primarily used for crop irrigation. The anchoring and float system of the plant allows it to adapt to changes in the reservoir`s water level without impacting its functionality.

The journey of the Lazer floating solar power plant began in 2017, and it emerged as the winner of the Energy Regulation Commission`s call for tenders in 2018. A crowdfunding campaign in 2021 successfully raised funds from local residents, allowing them to invest up to €179,000. Construction commenced the same year, involving geotechnical studies and the installation of anchors. The photovoltaic panels were assembled on floats, forming islands that were transported to their final location by boat. The plant is now operational and expected to operate for approximately three decades.

Bruno Bensasson, Executive Director of EDF Group`s Renewable Energies Division, highlighted the significance of the Lazer floating solar power plant in terms of innovation and expertise within the EDF Group: “For this first in France, EDF Renewables relied on its know-how developed abroad with four floating solar power plants built in the United States and Israel. By coexisting two sources of renewable electricity production on the same site, this project contributes to the achievement of the French objectives of carbon neutrality by 2050 while reducing the pressure on ordinary land.”

In addition to the Lazer facility, EDF Renewables plans to commission further new solar power plants in the Provence-Alpes-Côte d`Azur region in 2023, bringing their total solar production capacity in the area to 85MW. Furthermore, EDF Renewables is currently constructing the first pilot floating offshore wind farm, which will be located approximately 17 km off the coast of Port-Saint-Louis-du-Rhône.

New developments

Enel Green Power has begun construction of a new solar power plant at the Montelupone hydroelectric power plant in the Marche region of Italy. The initiative involves the installation of a photovoltaic roof over a diversion channel.

The 1km-long photovoltaic roof will have a capacity of 1MW, generating enough clean energy to power approximately 450 households. This setup is expected to reduce CO2 emissions by around 580 tons and save approximately 300 thousand cubic meters of methane consumption.

One of the significant advantages of this project is that it utilizes existing infrastructure, eliminating the need for additional land. The photovoltaic cover also minimizes the impact on the surrounding landscape.

In addition to renewable energy generation, the project offers various other benefits. CCTV cameras will be installed to deter theft and unauthorized water withdrawals, while fiber-optic cabling will facilitate the placement of hydraulic sensors, enhancing safety measures. An automated mechanism will promptly respond to water leaks by shutting down the flow upstream to mitigate the risk of flooding.

The project aligns with the region`s commitment to sustainability and water management. The photovoltaic cover`s shading effect will reduce evaporation, optimizing both hydropower production and irrigation withdrawal, particularly during periods of drought.

The Montelupone project, which is inspired by similar examples already implemented abroad, is the first Enel. It will however serve as a pioneer for similar initiatives, with plans underway for future projects, including one in Narzole, Piedmon,t which has already received authorisation.  These projects aim to leverage the potential of hydropower infrastructure by integrating solar panels on dams and implementing floating photovoltaic systems in load collection tanks.

Electricity Generating Authority of Thailand (EGAT) has also recently signed a contract with a consortium of Mitr Phol Energy Services Co, PEA ENCOM International Co and Dongfang Electric International Corporation (MPD Consortium) to build a hydro-floating solar hybrid project at the Ubol Ratana Dam in Khon Kaen Province.

The project at Ubol Ratana Dam is a part of EGAT`s clean energy development project. EGAT plans to develop an additional 15 hydro-floating solar hybrid projects nationwide to support renewable energy demands sustainably according to the national policy.

The 24MW project at Ubol Ratana Dam will generate electricity from clean energy by using a hybrid system that combines solar power and hydropower along with a Battery Energy Storage System (BESS) to help stabilize electricity generation from renewable energy.

This article first appeared in International Water Power magazine.