What are Floating Solar Plants? (A Complete Guide)
A few years ago, it would have been hard to imagine that we can generate electricity over the water surface. All we knew was- if you mix the two, you will get an electric shock! By this logic, one would wonder, how is a floating solar plant not a fire hazard?
But advancements in technology have turned this unexpected combination, of water and electricity, into a dependable solar solution.
Now, multi-megawatt solar projects are being set up over water bodies- to meet the rising power needs.
But what are these structures, and how do they work?
What is a Floating Solar Plant?
In floating solar systems or ‘floatovoltaics’, solar modules are made to float on water. The panels generate energy, that gets transferred to a transmission tower through underwater wires.
The first floating solar structure emerged in 2007, in Japan. But the plant was very small (20 kW) and got constructed for research purposes only. Seven years later, in 2014, the average capacity increased to 0.5 MW but scientists were still struggling to make this project work on a bigger scale.
The turning point came one year later when a larger plant of 7.55 MW got installed in Japan. After that, multi-megawatt capacity plants were established in many countries, especially in Asia.
We have more than 400,000 square kilometres (km2) area of man-made reservoirs in the world. If we go by this figure, then the potential for floating solar plants would be on a terawatt scale.
The Components of Floating Solar Plant
A floating solar plant structure consists of a buoyancy body that carries the PV modules, an anchoring system with mooring lines, and a power converter with cables.
Source: Maritime Engineering, ICE Virtual Library
The buoyancy body is made of polyethylene that can withstand 2.5 times its weight. It remains steady despite the water-level fluctuations. The vertical and horizontal frames are constructed out of anti-rust material. And, the solar modules have to be lead-free, dust-proof, and resistant to humidity and the effects of constant water jets. over, the wires are insulated as they stay underwater.
How it Works
The design of the system can vary.
For example, India’s largest floating power plant in Telangana is unique in its construction. The 100 MW Ramagundam plant is spread into 40 individual blocks. Each block has a floating surface that carries 11,200 solar modules.
It is unique because all the electrical equipment, from the inverter, and transformer to the supervisory control and data acquisition, is set up on floating Ferro-cement platforms. It doesn’t float away because the body is anchored to concrete blocks on the reservoir bed, through high modulus polyethylene ropes.
Before mounting, a thorough study of the topography of the water bed, its depth, and the water level variations is carried out.
But why go to such lengths when you can install a solar plant on land?
Acquiring land for solar projects is a difficult process. Power plants require large areas, which can be a huge financial burden. Land which is not suitable for agriculture and construction purposes has become scarce.
Also, solar plants are often set up in remote locations. Hefty investments have to be made in infrastructure, for transporting the power, and operation and maintenance. If projects are located in hilly terrains, site preparations get done, and the capital expenditure shoots up.
Keeping this lack of land availability in mind, solar developers have begun exploring water as a viable option. And they have been successful. Research has shown that floating solar photovoltaic power plant has 10.2% more generating capacity than land-based PV systems.
Where Can These Plants be Installed?
Floating solar plant in Meghadri Gedda Reservoir, Visakhapatnam
Floating solar plants are generally installed over artificial water bodies such as reservoirs and dams.
Man-made water bodies do not experience large waves. In the seas, such a system would have to withstand being hit by constant waves. Design and operation costs would increase significantly, as a result.
Also, the conjunction of solar plants set up over hydropower reservoirs offers a major advantage. The presence of existing grid connections and the necessary power infrastructure leads to huge cost savings. over, solar power supplements hydropower, leading to increased generation.
Floating solar panels could unlock clean power without wasting land
Scientists say “ floatovoltaics” hold promise, especially on hydropower reservoirs — but the environmental impacts are still unclear.
This story originally appeared in Eos and is part of Covering Climate Now, a global journalism collaboration strengthening coverage of the climate story.
Many countries bet on solar panels when engaging in the switch to cleaner energy. But the technology requires much larger areas than conventional fossil fuel plants to generate the same amount of electricity. An emerging solution to save space is to float the panels on bodies of water, an approach dubbed “ floatovoltaics.” Scientists believe this new approach could help solar energy to scale globally and fight climate change, but its environmental impacts are largely unexplored.
The world’s first commercial floatovoltaic system was installed on an irrigation pond at a California winery in 2008. Since then, bigger plants with capacities in the hundreds of megawatts have been built on lakes and hydropower reservoirs in China, and more are planned in Southeast Asia and Brazil.
“ Floatovoltaics are one of the fastest-growing power generation technologies today and a promising low-carbon energy source,” said aquatic ecosystem ecologist Rafael Almeida, an assistant professor at the University of Texas RIO Grande Valley.
Almeida explained that ideally, floating panels are placed in human-made bodies of water, such as irrigation channels and the reservoirs of hydropower plants, not taking up land that could otherwise be used for nature preserves or food production. Reservoirs at hydropower plants have the advantage of already having the infrastructure in place to distribute electricity.
Almeida and his colleagues calculated the potential of countries worldwide to use floatovoltaics on the basis of the area of their hydropower reservoirs. They found that countries in Africa and the Americas have the highest potential to generate energy with floatovoltaic technology. Brazil and Canada, for example, could become leaders in the sector because they require only about 5 % reservoir coverage to meet all their solar energy demands through midcentury. The scientists presented their results on December 12 at the American Geophysical Union’s fall meeting.
Get Caught Up
“ We have to seriously consider all possibilities to increase low-carbon energy production while minimizing land-use intensities,” said Almeida. “ But we also need to understand how to reduce unwanted social and ecological repercussions,” he added, explaining that we still know little about the impacts of covering large swaths of water with solar panels.
Regina Nobre, a freshwater ecologist at Paul Sabatier University in Toulouse, France, agrees. Nobre was not involved in the recent research but is part of a pioneering effort to monitor the environmental impacts of floatovoltaics in old gravel pit lakes in Europe. These pits were originally created for mining but typically fill with river water when abandoned and host diverse aquatic life. Nobre doesn’t have results yet but believes the evidence of their environmental impact study will be crucial for policymakers.
“ This technology is growing fast, and we urgently need more data to understand the impacts and give a better direction for environmental agencies and public policies,” she said.
For one thing, extensive panel coverage could block light in the water, Nobre said, altering the feeding and reproduction patterns of algae, which could lead to oxygen depletion in the lake and have cascading effects on the whole ecosystem, harming local fisheries and other wildlife.
Another possibility is that the panels could interfere with the exchange of greenhouse gases such as methane between the water and atmosphere, perhaps offsetting decarbonization benefits. But the real consequences are unpredictable without studies and will likely vary with different panel designs, area coverage and landscapes, both scientists pointed out.
“ We need to take a precautionary approach,” said Almeida. “ On one hand, we can’t put too many barriers to this potentially important sector to advance, but on the other hand, we need to understand the trade-offs and fill our prevailing knowledge gaps with more studies.”
Sofia Moutinho is a journalist writing about all subjects related to science, health and the environment.
Sierra Brava floating photovoltaic plant
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This initiative is a demonstration project created with the aim of studying the most suitable technical solutions for the installation of solar panels on lakes and reservoirs.
The installation is located close to the southern shore of the Sierra Brava reservoir, located in Zorita (Cáceres). Designed to cover around 12,000 m 2. the floating solar plant occupy around 0.07 % of the reservoir’s surface area.
The installation will consist of five adjacent floating systems. Each system will have 600 photovoltaic panels with an estimated total capacity of 1.125-megawatt peak (MWp).
The Sierra Brava floating PV plant will study different solar module technologies and configurations in terms of inclination, placing and orientation.among other parameters- together with a variety of flotation structures.
The project include environmental measures such as the installation of signage on the natural resources in the area around the reservoir, the installation of marker buoys to mark out the regulatory navigable areas, and the provision of nesting boxes and floating islands to encourage the nesting of certain bird species.
Environmental monitoring will be an important aspect, particularly on birdlife in the area, with the dual aim of protecting birds and studying their interaction with this kind of installation.
Another First For Floating Solar In New Jersey
The Cohoes project is weaving through the review process and it appears to be closing in on the finish line. Meanwhile, the energy firm New Jersey Resources was not to be caught napping. Though better known as the parent company of New Jersey Gas, NJR is also transitioning into renewables through its NJR Clean Energy Ventures subsidiary, which spotted another floating solar opportunity in New Jersey. In May of 2022, the company began construction on a floating array at a water supply reservoir owned by the New Jersey American Water company in Short Hills.
NJR Ventures and its partners announced completion of the array last week, upstaging Sayreville with a capacity of 8.9 megawatts.
“The clean power generated is enough to power 1,400 homes annually and will provide approximately 95% of the power needs for New Jersey American Water’s Canoe Brook Water Treatment Plant,” NJR Ventures explained in a press release. They also anticipate that the 16,510 solar panels in the array will help conserve water by reducing evaporation.
Everybody Into The Pool
Activity east of the Mississippi is also starting to bubble up. In 2021, the Township of Plainfield, Michigan, reached an agreement with solar installer White Pines Renewables to install a floating solar array on its water treatment plant. At the time, the township anticipated saving up to 5000 million in electricity costs over the life of the array.
“The Water Plant is the highest electricity user of all Township buildings,” Township officials noted in a press release. “Once fully operational, nearly 37% of the Water Plant’s electricity is projected to come from the solar panel system.”
While that project is working through the approval process, a ringing endorsement of the reservoir-to-solar trend has come from US Representatives Paul D. Tonko (D-NY) and Jared Huffman (D-CA), along with US Senator Angus King (I-ME). Last year the three legislators introduced a bill in support of a national floating solar policy called the POWER our Reservoirs Act, short for Protect our Waters and Expand Renewables on our Reservoirs Act.
“Floating solar offers tremendous opportunities to build a more sustainable clean energy future and protect our threatened water systems, including by reducing evaporation and preventing harmful algal blooms,” said Representative Tonko in a press statement earlier this year.
One aim of the POWER Act has already become law, with the authorization of 10 million for a US Army Corps of Engineers study of the potential for floating solar to alleviate drought as well as supply clean energy.
The other provisions add more muscle to the study of floating solar. The Act would also fund pilot programs at both the Army Corps of Engineers and the Bureau of Reclamation.
The Bureau of Reclamation is a public water supply agency that does not often grab the media spotlight, but it soon may start attracting more interest.
“Established in 1902, the Bureau of Reclamation is best known for the dams, powerplants, and canals it constructed in the 17 western states,” the agency explains. “These water projects led to homesteading and promoted the economic development of the West. Reclamation has constructed more than 600 dams and reservoirs including Hoover Dam on the Colorado River and Grand Coulee on the Columbia River.”
“Today, we are the largest wholesaler of water in the country. We bring water to more than 31 million people, and provide one out of five Western farmers (140,000) with irrigation water for 10 million acres of farmland that produce 60% of the nation’s vegetables and 25% of its fruits and nuts.” they add.
If that’s beginning to sound familiar, you may be thinking of the nation’s sprawling system of member-owned rural electric cooperatives. The REC system is a Depression-era program aimed at filling huge gaps in rural electricity access when private sector developers dropped the ball. REC’s exist to benefit their ratepayers and communities, not to profit investors.
RECs have been deploying their public benefit mission to push the rural solar envelope, including support for the emerging agrivoltaic industry. If all goes according to plan, the floating solar trend will hit high gear with the one-two punch of RECs and the 600 reservoirs of the Bureau of Reclamation.
Find me on Spoutible: @TinaMCasey or LinkedIn @TinaMCasey or Mastodon @Casey or Post: @tinamcasey
Photo: Solar array on a reservoir in Millburn, New Jersey courtesy of businesswire.com.
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