floating solar panels

Floating solar: what you need to know

Not every roof is suitable for solar panels – factors such as shade, obstructions, age, and available space can have property owners looking for other locations for installation. When it comes to large-scale solar projects, the most common alternatives to rooftop solar panel systems include ground mounts or solar canopies. Here’s a newer alternative that’s making quite the splash in the solar industry: floating solar.


Key takeaways


  • Floating solar, also known as floating photovoltaic (FPV) or floatovoltaics, is any sort of solar array that floats on top of a body of water. 
  • Floating solar has predominantly been installed in countries such as China, Japan, and the U.K and is quickly gaining popularity in the US as well, especially in California and New Jersey.
  • Floating solar comes with several advantages and some limitations that restrict the number of places it can be installed. 
  • Start your solar journey today through the EnergySage Marketplace, where you can receive multiple quotes from pre-screened installers to compare home solar equipment and financing options.

What’s in this article? 

What is floating solar and how does its work?

Floating solar, also known as floating photovoltaic (FPV) or floatovoltaics, is any sort of solar array that floats on top of a body of water. Solar panels need to be affixed to a buoyant structure that keeps them above the surface. If you come across a floating solar installation, it’s most likely located in a lake or basin because the waters are generally calmer than the ocean. It’s also common to install floating solar structures on large, man-made bodies of water, such as reservoirs. They are made up of anti rust material and are designed to be buoyant using polyethylene that can hold two and a half times its weight.

Floating solar is a relatively new concept. The first patents for this type of technology were registered in 2008. Since then, floating solar has predominantly been installed in countries such as China, Japan, and the U.K and is quickly gaining popularity in the US as well, especially in California and New Jersey.

Pros and cons of floating solar 

There are several advantages to installing a floating solar array versus more traditional types of projects. However, they also come with some limitations that make them unfit to install in certain areas.

ProsCons
No loss of valuable land space Cost 
High solar panel performance Applications 
Environmental benefits Disruption to aquatic life 
Can be installed at existing power plantsSite selection complications 

Pros of floating solar 

No loss of valuable land space

One of the biggest advantages of floating solar panels is that the installations do not require valuable and scarce land space. Many of these installations can take up unused space on bodies of water, such as hydroelectric dam reservoirs, wastewater treatment ponds, or drinking water reservoirs. This allows for landowners to make use of an area that wouldn’t otherwise be used, rather than installing on sunny land that could potentially serve another purpose down the line. Additionally, installing solar panels out on open water reduces the need for tree removal and forest clearing, a practice used in the case of some larger solar panel installations.

Higher solar panel performance

Solar panels are durable and can perform under high temperatures. But as with other electronics, with higher temperatures come decreased power outputs. Solar panel performance tends to decline as temperatures rise, which can be a concern for property owners looking to install panels in a hot and sunny climate. The bodies of water that host floating solar arrays help cool down the solar equipment, which means the panels produce electricity at higher efficiencies in hot climates than they might otherwise.

Environmental benefits

Floating solar panels can certainly play a role in contributing to healthier environments. With floating solar installations, water not only has a cooling effect on solar equipment: it works the other way as well. The floating solar panel structure shades the body of water and reduces evaporation from these ponds, reservoirs, and lakes. This is a particularly useful benefit in areas susceptible to drought, as water loss to evaporation can add up over time and contribute to a shortage.

The shade provided by these floating solar rays also help reduce the presence of algae blooms in bodies of freshwater. Algae blooms can be dangerous for human health if they occur in a source of drinking water, and can also lead to the death of plants and animals living in the body of water.

Lastly, floating solar panels are a source of clean, renewable electricity. The use of renewable energy technologies helps decrease the emissions of greenhouse gas emissions and other pollutants into the atmosphere, leaving a positive impact on the natural environment as well as human health.

Can be installed at existing power plants

Many hydropower dams have a nearby lake to hold excess water. The panels can be installed on these lakes and directly send electricity to the grid from the existing infrastructure at the power plant. This hybrid system allows for more energy production with minimal new technology.

Cons of floating solar 

Costs 

Floating solar installations may require additional costs than more traditional types of solar panel installations. Because this is a relatively new technology that requires specialized equipment and more niche installation knowledge, it typically requires a higher price tag than installing similar-sized solar farms on rooftops or solid ground. But as with traditional solar panel systems, the costs of installing floating solar panels are expected to continue to drop as the technology advances.

Applications 

Floating solar installations don’t work for just anyone. The majority of floating solar installations are large-scale and provide power for utility companies, large communities, companies, or municipalities. If you’re looking into solar for your home, then it makes much more sense to install a rooftop or ground-mounted system. Those that invest in floating solar often have access to a large body of water to fit hundreds or thousands of solar panels. Unlike these types of installations, the average residential solar panel system has roughly 20 panels. Installation companies and developers installing floating solar projects today are not doing so on small-scale installations.

Disruption to aquatic life 

The installation prevents sunlight from penetrating into the surface of the water, thus limiting the wildlife within the water. The physical structure may also injure animals – therefore, it is recommended that the panels are installed on man made lakes and reservoirs that have limited wildlife in them.  

Site selection complications

Site selection is a critical aspect of installation. Factors such as wind speed, anchoring ability, movement patterns of the water all must be studied in depth before undertaking a project on the water body. Anchoring helps limit the movement of the solar island by natural factors and ensures there is no risk of damage and crashing into the shore of other structures. 

Notable floating solar companies and installations

Floating solar is increasing in popularity in the world and recently in the United States as well. Let’s take a look at some of the most notable floating solar installations: 

First public floating solar system in America

  • Location: Kelseyville county, California, USA
  • Company: Ciel & Terre
  • Size: 252 kilowatts (kW)

Ciel & Terre installed the first public floating solar installation in the United States. Comprised of 720 solar panels, this structure floats on top of a man-made wastewater treatment pond. The Lake County Special District financed this system through a municipal lease, whichhas them realizing solar savings from the get-go.

Largest floating solar system in America 

  • Location: Healdsburg Floating Solar Farm, California
  • Company: White Pine
  • Size: 44.8 megawatts (MW)

This installation sits on two ponds, spanning fifteen acres and provides 8 percent of Healdsburg’s annual electricity requirement. It has double sided solar panels capturing the overhead sunlight as well as the rays the water reflects back. 

Largest installation in the world 

  • Location: Dezhou Dingzhuang Floating Solar Farm, China 
  • Company: Huaneng Power International (HPI)
  • Size: 320 MW

As of 2022, this is the largest farm in the world, and was constructed in two phases by Huaneng Power International (HPI). The project is located in a reservoir in Shandong, an eastern province of China on the Yellow Sea. The system is connected to a wind farm ​​and a battery storage system and is expected to generate 550 million kilowatt-hours (kWh) of electricity per year.

Japan’s largest floating solar structure 

  • Location: Chiba Prefecture, Japan
  • Company: Kyocera
  • Size: 13.7 MW

Kyocera, a popular Japanese solar panel manufacturer, developed what is currently Japan’s largest floating solar installation. The system takes up more than 44 acres of space and generates power for Tokyo Electric Power Company (TEPCO).

The U.S. Army’s first floating solar structure 

  • Location: Big Muddy Lake, Fort Bragg, North Carolina
  • Company: Procured through Ameresco
  • Size: 1.1 MW

This installation is the largest of its kind in the Southeastern United States and is the first solar array deployed by the United States Department of Defense. The system currently powers 190 homes and includes 2 megawatt-hours (MWh) of battery storage. This project was completed in conjunction with the Army’s efforts to reduce greenhouse gas emissions by 50 percent by 2030 and attain net zero by 2050. 

Explore your solar options

While floating solar is more viable as a commercial project, finding the right solar system for your home means comparing multiple quotes from solar installers. Using the EnergySage Marketplace, you can find local solar installers near you, and make easy side-by-side comparisons of all your solar options, including equipment. You’ll receive multiple quotes from pre-screened installers to compare equipment, financing options, costs, savings, and more!


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About Ananyaa Mehra

Ananyaa is a researcher in electrification, renewable energy, and green technology, with a focus on policy and equity. She’s a junior at Tufts University pursuing a Bachelor's degree in Environmental Studies. On campus, Ananyaa is involved with the Energy Club and Sustainability Council and serves as an organizer of the annual Tufts Energy Conference. Ananyaa is especially passionate about protecting our oceans, where she loves to spend time.