If solar energy use is to increase dramatically, many rooftops and plots of land need to be covered in photovoltaic (PV) modules. Roofs are often excellent for solar panels, but not all are well-suited for them, and vacant land is often scarce and expensive in urban and suburban areas. Another idea is to use the vast area of the Earth covered in water to generate solar power.
Thus, a newer alternative, floating panel systems or floatovoltaics, is gaining popularity for certain applications. But are floating solar panels the new frontier of clean energy or too expensive and impractical? Let’s explore this innovative topic to find out.
What Are Floatovoltaics?
Floating photovoltaics (FPV) projects have solar modules that float on a body of water, including lakes, lagoons, ponds, reservoirs, and rivers. The PV panels need to be above the surface of the water, so they are usually attached to something buoyant that doesn’t rust easily. Floating solar farms are gradually becoming more widespread, especially near densely populated areas where vacant land is scarce or prohibitively expensive.
Some of the most common placements of floating solar panel farms currently include hydroelectric dam reservoirs, drinking water reservoirs, and wastewater treatment ponds. These manufactured bodies of water are already disturbed sites, and hydropower plants have existing power transmission infrastructure for distributing the hydropower.
However, some solar developers are also experimenting with mounting solar panels out at sea on offshore solar farms. Oceans cover 70% of our planet's surface, so there is ample space for mounting PV panels. However, installing floating solar panels at sea can present additional challenges.
Potential Benefits Of Floatovoltaics
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 is concern that converting farmland to utility-scale solar farms could harm food security. However, floatovoltaics take up little or no land area and take advantage of space with few, if any, other development opportunities.
Solar panel efficiency often decreases when they heat up above 77°F. For example, most solar panels have a temperature coefficient of -0.3%°C to -0.5%°C. That means that for every degree Celsius, the efficiency reduces by a fraction of a percent. Unfortunately, in hot climates, this reduction in efficiency can really reduce solar power output. Mounting solar PV panels above water can have a natural cooling effect, boosting solar energy production. Likewise, using bifacial solar panels allows the modules to generate power from both sides. This allows electricity production from the light that reflects off of the water.
Another benefit of floatovoltaics is that modules can help shade the body of water, preventing freshwater evaporation. This can be especially beneficial in dry climates or during droughts. In fact, a 2021 study showed that covering 4,000 miles of California canal with solar canopies could conserve 65 billion gallons of water annually by reducing evaporation. Thus, California has excellent photovoltaic potential.
Solar contractors installing floating solar farms at hydroelectric dam reservoirs can often use the existing utility infrastructure for solar energy, reducing development costs. Likewise, solar engineers are also examining combining offshore wind farms and floating solar farms, which can use the same transmission line. For example, a project with 5 megawatts of solar capacity is planned in the North Sea near the Netherlands, aiming to begin operation in 2026.
Current Roadblocks For Floating Solar Panels
Although floating solar farms offer many benefits, there are some disadvantages to overcome. Typically, there are more challenges with floating solar installations located in salt water because salt water can leave a film on the modules, decreasing solar energy output. This can also be an issue for land-based projects near the ocean that receive salt spray.
Because floating solar farms are less common, they require special equipment that keeps the modules above the surface of the water. This is more sophisticated and complex than standard roof or ground-mounted racking systems. Also, because this is a niche market, these materials can be more expensive, driving up costs.
These solar projects are also more complex from an engineering standpoint due to potential wind speeds, corrosion, anchoring complications, and water movement. Site selection can be difficult and time-consuming, increasing permitting issues and development and construction costs.
Constructing floating solar power plants can also damage the environment and disrupt aquatic life, especially in pristine areas. Once installed, the modules shading the water's surface reduce available sunlight, altering ecosystems. For example, research has shown that floating solar farms can impact a water body's stratification. Changes in water stratification can cause the lower layers to become deoxygenated, increasing nutrient concentrations and killing fish. More research is needed to learn about the ecological implications of floating solar.
NEC Guidelines for Floatovoltaics
The National Electrical Code (NEC) provides safety guidelines for all electrical installations, including floatovoltaics projects. Key NEC considerations for floating solar farms include:
Grounding and Bonding (NEC 690): Proper grounding is essential to ensure safety from electrical faults. Floating structures need specialized grounding techniques to prevent electrical hazards due to water presence.
Wet Locations (NEC 682): Floatovoltaic systems are installed in water, classifying them as "wet locations." NEC 682 outlines requirements for electrical equipment in such environments, including corrosion-resistant materials and watertight enclosures.
Wiring Methods (NEC 310): Conductors must be suitable for wet environments, and insulation types must withstand water exposure, UV radiation, and potential mechanical damage.
Overcurrent Protection: Overcurrent devices must be designed to handle the unique challenges posed by floatovoltaic systems, such as water proximity and potential flooding.
Maintenance Access and Safety: Adequate access for inspection and maintenance is required, as outlined in NEC 110. This ensures safety during system servicing.
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What are the Pros and Cons of Floatovoltaics?
The pros and cons of floating solar panels present a mixed bag of advantages and challenges.
Pros of Floatovoltaics | Cons of Floatovoltaics |
Additional solar energy generation without using additional land | Initial installation cost |
Utilization of water bodies like reservoirs, ponds, and dams | Potential impact on aquatic ecosystems |
Water cooling leads to higher electricity output | Solar maintenance and cleaning challenges |
Reduction in water evaporation, saving water resources | Limited scalability on small water bodies |
Reduction in algal growth and evaporation-induced salt concentration | Potential shading impact on aquatic organisms |
Potential benefits to aquatic vegetation and ecosystem | Limited use in areas with cold climates |
Dual land use and renewable energy generation opportunity | Regulatory and solar permitting challenges |
Reduced conflicts with other land use purposes | Limited floatovoltaic technology maturity and proven performance |
Visual appeal and possible increased public acceptance | Site-specific considerations for floating solar panel projects |
What Floatovoltaic Projects Exist Today?
Numerous countries, including China, India, Taiwan, South Korea, Germany, the Netherlands, and the United States, are constructing utility-scale floating solar farms. Although some are operational, many are in various stages of development.
China
The largest operational floating solar panel project is 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 8-megawatt hours of battery energy storage. The floatovoltaic project was developed by Huaneng Power International (HPI) and was constructed near the 2.65 GW Dezhou thermal power station.
Taiwan
One of Taiwan's largest near-shore floatovolatics projects was completed in the Changbin Industrial Zone, with a total installed capacity of 440 MWp. This project was an extension 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.
South Korea
The largest planned FPV project is the Saemangeum floating solar farm in South Korea. This 2.1-gigawatt project aims to be operational in 2030 and can help the country significantly reduce its dependence on fossil fuels. It will be located in tidal flats on the Yellow Sea coast, co-located with an onshore solar farm.
The floatovoltaic project is currently in the pre-construction phase, and multiple phases are planned for its development. Once completed, the Saemangeum floating solar farm will contribute to South Korea's renewable energy goals and help increase its clean energy generation capacity.
India
A 600-megawatt floating solar panel plant is being constructed near the Omkareshwar Dam on the Narmada River. This project is set to be the world's largest floating solar energy project and is expected to be commissioned.
The plant is being constructed on the reservoir of the Omkareshwar Dam, located in Khandwa district, Madhya Pradesh, India. The ambitious 600 MW project is driven by the state-owned Rewa Ultra Mega Solar Limited (RUMSL) and will help generate clean energy from the abundant solar resources in the region.
North America
By contrast, the largest floatovoltaics installation in North America is currently the NJR Clean Energy Ventures (CEV) floating solar installation in Millburn, New Jersey. With a capacity of 8.9 MW, it consists of 16,510 solar panels installed on a reservoir located at the New Jersey American Water Canoe Brook Water Treatment Plant.
Floating solar panels can also help reduce evaporation, protect the water source, and benefit the environment. The innovative racking system enables the panels to float on water, providing a practical solution to finding suitable locations for large-scale commercial solar installations.
Europe
The largest floating solar panel farm in Europe is located in Portugal's Alqueva reservoir. The project consists of almost 12,000 floating photovoltaic panels, covering an area equivalent to four football fields.
With a capacity of 70 MW, it is a significant renewable energy installation and forms part of a larger hybrid farm with a total expected capacity of 154 MW. This floatovoltaic park helps Portugal increase its clean energy generation and reduce greenhouse gas emissions.
SolarDuck, a Dutch-Norwegian floating solar developer, plans to develop a 500-kilowatt offshore pilot project in the North Sea1. This project aims to demonstrate the feasibility and effectiveness of floating solar technology in offshore environments. SolarDuck aims to generate clean, renewable energy and contribute to the transition to a more sustainable energy system by harnessing the abundant sunlight in the North Sea.
How Much Do Floating Solar Panels Cost?
The cost of floating solar farms varies depending on numerous factors, including the cost of anchoring systems, transmission infrastructure, real estate leases, labor, and system capacity. For example, the Saemangeum project is estimated to cost $3.82 billion, and the smaller floating solar farm on the Narmada River costs $4.1 million.
Some more experimental projects, such as the Dutch project in the North Sea, are still in the pilot phase. Thus, floatovoltaics are much more expensive per MW because they are smaller in scale and require more research.
What Research Is Needed to Advance Floatovoltaics?
More research is needed to improve the efficiency of current floating solar panel systems and lower their costs to advance floatovoltaics. Researchers can further analyze the impacts of environmental factors like wind and waves on solar panel orientation and positioning and develop better anchoring systems. Efforts can also be directed towards 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 on the most effective integration of floating solar photovoltaic systems with existing onshore and offshore renewable energy infrastructures 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, having developed and constructed numerous systems in the United States. They specialize in all aspects of floating PV systems, from design and engineering to construction and maintenance.
Another company involved in floating offshore solar projects is SolarDuck, a Dutch-Norwegian developer planning a 500-kilowatt offshore pilot project in the North Sea. Solarduck is known for its innovative floating solar solutions that are designed to withstand harsh offshore conditions while maximizing energy production and minimizing environmental impact.
Floatovoltaics: Solar Installations Of The Future?
Although floating solar panels are promising in certain areas, they are not ideal for all locations. This application is most appealing in areas where land is scarce, and existing transmission infrastructure is in place. Often, the most attractive sites are reservoirs at hydroelectric dams, but some solar developers are examining ocean-based applications at offshore wind farms and tidal flats.
Although many floating solar projects have been completed, more research is needed to advance this approach. For example, research is needed to understand the ecological impacts of floatovotaics or the best way to anchor them.
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