Floating solar—floatovoltaics—is a basic yet powerful idea. Rather than having solar panels on land, we place them on floating platforms on top of bodies of water. Consider dams, reservoirs, abandoned quarries, or irrigation canals. These platforms support arrays of photovoltaic panels, producing clean electricity just as rooftop or ground-based systems do, but with some unexpected benefits.

Why Use Water?

On a first glance, placing solar panels on water may appear unnecessary. Yes, we have considerable land and sunny rooftops to utilize. But with an increasing population, the need for land increases too. Agriculture, woodlands, houses, and businesses all fight for the same space. That’s where floating solar comes into its own—it allows us to use underutilized water surfaces without encroaching on precious land resources.

And there’s a plus on top of that. Solar panels are more efficient when they are cool. Overhanging water is a natural cooling measure that improves the panels’ performance. Estimates are that there is a 5 to 15 percent gain in efficiency over similar land-based systems. So we’re not just utilizing space more efficiently, but we’re getting more juice from the sun while we’re doing it.

Assisting in Minimizing Water Loss

In a nation like Australia, where drought is ever-present, conservation of water is paramount. That’s just another way floating solar has genuine advantages. By putting solar panels over sections of reservoirs and dams, we minimize direct sunlight exposure and evaporation. There are studies that indicate floating solar can reduce evaporation by up to 50 to 80 percent. That’s water conserved for drinking, agriculture, or even for firefighting.

Plus, the shading effect of these panels helps reduce the growth of algae in the water. That means cleaner water and less strain on filtration systems. We’re essentially creating a two-for-one environmental benefit: renewable energy generation and better water management.

A Natural Fit for Australia

Thanks to our solar abundance, our extensive water reservoirs, and our push for decarbonisation, floating solar just makes sense in Australia. It’s particularly appealing where land costs are high or in short supply, such as in city centers or around national parks and agricultural land. Rather than clearing bushland or taking up prime agricultural land, we can construct energy infrastructure on the surfaces of existing water bodies that are already cared for and regulated.

We have already witnessed some encouraging innovations here. In South Australia, a winery installed a floating solar array on its irrigation dam and lowered both energy bills and water evaporation at the same time. And then there are utility-scale ventures in the works, including feasibility studies for installations on dam reservoirs in Victoria and Queensland.

Even mining operations are exploring floating solar as a means to energize remote operations. Since many mines already possess water catchment or tailings dams on site, topping them with solar panels is logic—particularly when diesel fuel is costly to ship and is detrimental to the environment.

How Does It Work?

The system is comparable to ground-mounted solar farms in that they produce electricity, but the support structures are clearly different. Floating solar platforms consist of floatant, UV-stable materials—most often high-density polyethylene—which bear the panels and stabilize them.

Cables join the system to shore, where inverters and transformers regulate the conversion of sunlight into useful electricity. Anchoring systems are also important. Depending on the water body, these may be anchored to the shoreline, weighted to the seafloor, or even made to float with fluctuating water levels.

It’s more than placing panels on a raft. Engineers need to factor in wind loads, water flows, waves, and maintenance access. Yet as technology comes of age, these systems become more modular and scalable, so they cost less and are simpler to install.

What Are the Challenges?

As with any new technology, floating solar also has its disadvantages. The first one is cost. Floating systems tend to be more costly to install compared to land-based arrays because of the specialized structures, anchoring, and corrosion-proof components. However, that initial expense can pay for itself in the long run through the increased energy output and water management savings.

And then there is the issue of environmental footprint. While shading can prevent evaporation and algae overgrowth, it could otherwise influence aquatic organisms if not properly planned. That’s why site analysis is a must. We have to know about the local environment, water consumption, and present biodiversity prior to deciding on a floating array.

Maintenance is another factor to consider. With work over water, there are new issues—technicians will require boats or floating platforms to reach the system. And protecting against electrical malfunction in a wet environment means that insulation and equipment design must meet very high standards.

These are not, however, show-stoppers. With careful planning and design, floating solar can be as safe and reliable as land-based systems.

A Strong Case for Hybrid Systems

Perhaps the most thrilling innovation in floating solar is its ability to be integrated with pre-existing hydropower dams. Together, we get a hybrid system that’s more than the sum of its elements. On sunny days, solar panels dominate. On cloudy days or nighttime, the hydro plant comes into action. We have round-the-clock, flexible renewable energy using existing assets.

This type of synergy can enhance grid stability and less dependency on fossil fuels. And since we’re harnessing infrastructure that’s already linked to the grid and owned by energy companies, floating solar can be deployed more quickly and smoothly.

In Tasmania and rural Queensland, this can be a game-changer. We already have the dams. Why not cap them with renewable energy?