If solar energy use is to increase dramatically, many rooftops and lots must be covered with photovoltaic (PV) modules. Rooftops are often a great place for solar panels, but not all are well suited to them, and vacant land is often scarce and expensive in urban and suburban areas. Another idea is to use the Earth’s vast water-covered surface to generate solar power.
Thus a newer alternative, floating panel systems or floatovoltaics, is gaining popularity in some applications. But are floating solar panels the new frontier of clean energy, or are they too expensive and impractical? Let’s examine this innovative topic to find out.
What are floating solar panels?
Floating photovoltaic (FPV) projects involve solar modules that float on bodies of water, including lakes, lagoons, ponds, reservoirs and rivers. The photovoltaic panels must be above the surface of the water, so they are usually attached to something that won’t rust. Floating photovoltaic farms are becoming more common, especially near densely populated areas where free land is scarce or too expensive.
Some of the most common locations for floating solar farms today include hydroelectric dams, drinking water reservoirs and wastewater treatment ponds. These manufactured water reservoirs are already breached sites, and the hydroelectric plants have existing transmission infrastructure to distribute hydropower.
However, some solar developers are also experimenting with installing solar panels at sea in offshore solar farms. The oceans cover 70% of the planet’s surface, so there is plenty of room to install photovoltaic panels. Installing floating solar panels at sea, however, may come with additional challenges.
Potential benefits of floating photovoltaic panels.
Locating utility-scale renewable energy projects near population centers is ideal, but available land is relatively scarce and expensive in most urban areas. In rural farming communities, where land is more plentiful, there are concerns that converting agricultural land into utility-scale solar farms could be detrimental to food security. Floating photovoltaic cells, however, occupy little or no land and utilize space that has few, if any, other opportunities for development.
The efficiency of solar panels often decreases when they get hotter than 25°C. For example, most solar panels have a temperature coefficient of -0.3%°C to -0.5%°C. This means that for every degree Celsius, the efficiency drops by a fraction of a percent. Unfortunately, in hot climates, this drop in efficiency can really reduce solar output. Mounting photovoltaic panels over water can have a natural cooling effect, increasing solar output. Similarly, the use of dual-surface solar panels allows modules to generate power from both sides. This allows electricity to be produced from light reflecting off the water.
When solar contractors install floating solar farms on hydroelectric dam reservoirs, they can often leverage existing power infrastructure to harvest solar energy, reducing development costs. Similarly, solar engineers are also exploring a combination of offshore wind farms and floating solar farms that can use the same transmission line. For example, a 5-megawatt project is planned in the North Sea near the Netherlands and is expected to be operational in 2026.
Current obstacles to floating solar panels.
Although floating photovoltaic farms have many advantages, there are some drawbacks to overcome. Typically, there are more challenges associated with floating solar installations located in salt water, as salt water can leave a film on the modules, reducing solar energy production. This can also be a problem for land-based projects near the ocean, which are exposed to salt spray.
Because floating photovoltaic farms are less common, they require special equipment to keep the modules above the water’s surface. This is more sophisticated and complex than standard rooftop or ground-based systems. In addition, because it is a niche market, the materials can be more expensive, which adds to the cost.
These solar projects are also more complex from an engineering standpoint due to potential wind speeds, corrosion, anchoring complications and water movements. Site selection can be difficult and time-consuming, adding to permitting issues and development and construction costs.
The construction of floating solar power plants can also harm the environment and disrupt aquatic life, especially in pristine areas. Once installed, the modules that shade the water’s surface limit access to sunlight, altering ecosystems. For example, studies have shown that floating solar farms can affect water stratification. Changes in water stratification can deoxygenate the lower layers, increasing nutrient concentrations and killing fish. More research is needed to learn about the ecological consequences of floating solar farms.
What are the advantages of floating photovoltaics?
- Additional solar power generation without using additional land.
- Initial installation cost.
- Use of water bodies such as reservoirs, ponds and dams.
- Potential impact on aquatic ecosystems.
- Water cooling leads to higher electricity production.
- Challenges associated with maintenance and cleaning of solar cells.
- Reduction in water evaporation, saving water resources.
- Limited scalability on small bodies of water.
- Reduced algae growth and salt concentration due to evaporation.
- Potential impact of shading on aquatic organisms.
- Potential benefits to aquatic vegetation and ecosystem.
- Limited use in areas with cold climates.
- Potential for dual land use and renewable energy generation.
- Regulatory and permitting challenges for solar energy.
- Limited conflicts with other land use objectives.
- Limited maturity of floatovoltaic technology and proven performance.
- Visual appeal and possible increased public acceptance.
- Specific considerations for floating solar panel projects.
What floating photovoltaic panel projects exist today?
Numerous countries, including China, India, Taiwan, South Korea, Germany, the Netherlands and the United States, are building utility-scale floating solar farms. While some are already in operation, many are at various stages of development.
The largest floating solar panel project in operation is the Dingzhuang solar farm in eastern China. This 320-megawatt floating solar farm is mounted on a reservoir, is connected to a 100-megawatt wind farm, and has an 8-megawatt-hour energy battery. The floating solar power plant project was developed by Huaneng Power International (HPI) and was built near the 2.65 GW Dezhou Thermal Power Plant.
One of the largest floating solar projects in Taiwan was completed in the Changbin industrial zone, with a total installed capacity of 440 MWp. The project was an expansion of a previous floating solar project built by Ciel & Terre Taiwan in 2020. It contributes to Taiwan’s renewable energy goals and helps reduce carbon emissions.
The largest planned FPV project is the Saemangeum floating solar farm in South Korea. The 2.1-gigawatt project is scheduled to come online in 2030 and could help the country significantly reduce its dependence on fossil fuels. It will be located on tidal plains on the coast of the Yellow Sea, in conjunction with an onshore solar farm.
The floatovoltaic project is currently in the pre-construction phase, with development planned in several stages. When completed, the Saemangeum floating solar farm will contribute to South Korea’s renewable energy goals and help increase its capacity to generate clean energy.
A 600-megawatt floating solar power plant is being built near the Omkareshwar Dam on the Narmada River. The project is expected to be the world’s largest floating solar power project and is expected to be commissioned. The power plant is being built on the Omkareshwar Dam reservoir, located in Khandwa district in the state of Madhya Pradesh, India. The ambitious 600 MW project is being led by state-owned Rewa Ultra Mega Solar Limited (RUMSL) and will help generate clean energy from the region’s abundant solar resources.
In contrast, the largest floating PV installation in North America is currently the NJR Clean Energy Ventures (CEV) floating PV plant in Millburn, New Jersey. It has a capacity of 8.9 MW and consists of 16,510 solar panels installed on a tank located at the New Jersey American Water Canoe Brook water treatment facility.
The floating solar panels can also help reduce evaporation, protect the water source and benefit the environment. An innovative racking system allows the panels to float, providing a practical solution for finding suitable locations for large-scale commercial solar installations.
The largest floating solar farm in Europe is located in Portugal’s Alqueva Reservoir. The project consists of nearly 12,000 floating photovoltaic panels with an area equivalent to four football fields. With a capacity of 70 MW, it is a significant renewable energy installation and is part of a larger hybrid farm with a total expected capacity of 154 MW. This floating photovoltaic park helps Portugal increase clean energy production and reduce greenhouse gas emissions.
SolarDuck, a Dutch-Norwegian developer of floating solar power plants, is planning a 500 kilowatt offshore pilot project in the North Sea1. The project aims to demonstrate the feasibility and effectiveness of floating solar technology in a marine environment. By taking advantage of the abundant sunlight in the North Sea, SolarDuck intends to generate clean, renewable energy and contribute to the transition to a more sustainable energy system.
How much do floating solar panels cost?
The cost of floating solar farms varies depending on a number of factors, including the cost of anchoring systems, transmission infrastructure, property leases, manpower and system capacity. The Saemangeum project, for example, is estimated to cost $3.82 billion, while a smaller floating solar farm on the Narmada River costs $4.1 million.
Some more experimental projects, such as a Dutch project in the North Sea, are still in the pilot phase. Floating photovoltaic farms are therefore much more expensive per MW because they are smaller in scale and require more research.
What research is needed to develop float photovoltaics?
More research is needed to improve the efficiency of current floating solar panel systems and reduce their costs in order to develop float photovoltaics. Researchers can further analyze the effects of environmental factors, such as wind and waves, on the orientation and positioning of solar panels and develop better anchoring systems. Efforts can also be directed toward creating more environmentally friendly materials for floating solar panel systems, ensuring that installations do not harm marine ecosystems. Finally, there is also a need for research into the most effective integration of floating photovoltaic systems with existing onshore and offshore renewable energy infrastructure to improve energy storage and distribution.
What companies specialize in floatovoltaics?
Several companies specialize in floating solar panels. One such company is D3Energy, a leader in floating solar applications, which has developed and built many systems in the United States. It specializes in all aspects of floating photovoltaic systems, from design and engineering to construction and maintenance.
Another company involved in floating marine solar projects is SolarDuck, a Dutch-Norwegian developer planning a 500 kilowatt marine pilot project in the North Sea. Solarduck is known for its innovative floating solar solutions, which are designed to withstand harsh conditions at sea while maximizing energy production and minimizing environmental impact.
Floatovoltaics: the solar installations of the future?
While floatovoltaic projects are promising in some areas, they are not ideal for all locations. This application is most attractive in areas where land is scarce and there is existing transmission infrastructure. Often the most attractive locations are reservoirs at hydroelectric dams, but some solar developers are exploring ocean-based applications on offshore wind farms and tidal.
Although many floating projects have already been completed, more research is needed to develop this approach. For example, research is needed to understand the environmental impact of floating solar farms or how best to anchor them.