Floating solar panels (floatovoltaics): what 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. Regarding large-scale solar projects, the most common alternatives to rooftop solar panel systems include ground mounts or solar canopies. Here's a newer choice making a splash in the solar industry: floating solar.

Floating solar, also known as floating photovoltaic (FPV) or floatovoltaics, is any solar array that floats on top of a body of water. Solar panels must 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. Installing floating solar structures on large, artificial bodies of water, such as reservoirs, is also common. 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, especially in California and New Jersey.

Installing a floating solar array has several advantages over more traditional projects. However, they also come with limitations that make them unfit to install in certain areas.

Pros of floating solar

No loss of valuable land space

One of the most significant 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 landowners to use an area that wouldn't otherwise be used rather than installing it on sunny land that could serve another purpose. 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 concern 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 undoubtedly play a role in contributing to healthier environments. With floating solar installations, water has a cooling effect on solar equipment and works the other way. The floating solar panel structure shades the body of water and reduces evaporation from these ponds, reservoirs, and lakes. This is beneficial 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 helps 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. Using renewable energy technologies helps decrease greenhouse gas emissions and other atmospheric pollutants, positively impacting the natural environment and 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 drop as technology advances.

Applications 

Floating solar installations don't work for just anyone. Most 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, installing a rooftop or ground-mounted system makes much more sense. 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

Installation prevents sunlight from penetrating the water's surface, thus limiting the wildlife within the water. The physical structure may also injure animals; therefore, the panels are recommended to be installed on artificial lakes and reservoirs with limited wildlife.  

Site selection complications

Site selection is a critical aspect of installation. Factors such as wind speed, anchoring ability, and movement patterns of the water 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. 

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. This structure is composed of 720 solar panels and floats on an artificial wastewater treatment pond. The Lake County Special District financed this system through a municipal lease, which has them realizing solar savings from the get-go.

Most extensive 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 and the rays the water reflects. 

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 annually.

Japan's largest floating solar structure

• Location: Chiba Prefecture, Japan

• Company: Kyocera

• Size: 13.7 MW

Kyocera, a famous Japanese solar panel manufacturer, developed 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 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 two megawatt-hours (MWh) of battery storage. This project was completed with the Army's efforts to reduce greenhouse gas emissions by 50 percent by 2030 and attain net zero by 2050. 

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 easily compare all your solar options, including equipment. You'll receive multiple quotes from pre-screened installers to compare equipment, financing options, costs, savings, and more!