‘Float-ovoltaics‘: How floating solar panels in reservoirs could revolutionise global power
Covering reservoirs with floating solar could produce three times as much energy as the EU currently does, a study has found.
Floating solar panels on reservoirs could produce three times as much electricity as the entire EU, a new study has shown.
Solar panels are one of the cheapest and most efficient ways of generating electricity but they also take up a lot of space.
Innovative schemes have seen them attached to car parks, trash heaps, and farms. Now, researchers are urging governments to invest in floating solar.
According to a study published in the journal Nature, covering 30 per cent of the surface of the world’s 115,000 reservoirs with solar could generate 9,434 terawatt hours of power annually.
That’s more than triple the energy production of the EU, which reached 2,785.44 terawatt hours in 2021.
How do floating solar panels work?
To achieve net zero, countries need to invest in renewable energy.
According to a 2021 study, countries might need to devote between 0.5 and 5 per cent of their land area to solar panels in order to fully decarbonise. Solar may be far better for the planet than natural gas. but it takes up about 70 times as much land per unit of energy.
When space is at a premium, planners can end up at loggerheads with farmers, local authorities, and conservationists.
Floating solar could provide a solution.
They are just like normal ‘photovoltaic’ cells, which generate electricity from sunlight. The only difference is that they float on pontoons. earning them the nickname ‘floatovoltaics.’
Solar needs a stable, unshaded water surface. making an irrigation canal, quarry lake, or reservoir the ideal location.
The first floatovoltaic system was installed in 2008. The Dezhou Dingzhuang Floating Solar Farm in China is the largest facility in the world and covers nearly 600 hectares.
What is the potential of floating solar?
Less than one per cent of the world’s solar installations are currently floating. but according to the study in Nature, they have “huge potential.”
“Considering the proximity of most reservoirs to population centres and the potential to develop dedicated local power systems, we find that 6,256 communities and/or cities in 124 countries, including 154 metropolises, could be self-sufficient with local FPV (floating photovoltaic) plants,” the authors write.
Floating solar could also prevent water loss from evaporation. According to the study, installing this much solar would save enough water to supply 300 million people per year.
What are the environmental benefits of solar?
As the world heats up, keeping fossil fuels in the ground is increasingly important.
According to the GLOBAL Carbon project, we have 380 billion tonnes of CO2 left in the global carbon budget.
This is the amount of carbon dioxide we can release and still have a 50 per cent chance of avoiding 1.5 degrees of warming.
In 2022, carbon emissions reached an all-time high of 36.8 billion tonnes.
But it’s not all bad news. Countries are also pouring money into renewables. In 2022, wind and solar produced a fifth of the EU’s electricity. the first time clean energy sources have produced more electricity than fossil gas.
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Floating Solar: 8 Things You Need To Know
Solar power has grown in popularity in recent years as a result of the global push for renewable energy. While ground-mounted solar panels are the most common way to harness the power of the sun, floating solar is becoming increasingly popular. This power generation system makes use of large bodies of water to set up a floating solar unit that captures enough solar energy without the need for land.
What Is Floating Solar and How Does Its Work?
Solar panels that are mounted on floating structures are referred to as floating solar or floating photovoltaics (FPV). Floating solar systems are commonly used in reservoirs, lakes, and other large bodies of man-made water. The primary benefit of FPV is that it makes use of unused space on the water’s surface and does not consume valuable land resources.
The solar panels are firmly attached to buoyant structures to keep them afloat on water bodies and receive adequate sunlight all year. The generated solar electricity is routed to a central inverter before reaching electrical equipment onshore via underwater cables. The power from the inverter is sent to the transformer for stepping down before being fed to the transmission system for delivery to the end user.
The deployment of FPVs in solar bodies of water is a win-win scenario. As the panels prevent excessive heat from entering the water bodies, they cool themselves, increasing energy productivity.
Components of Floating Solar System
PV modules: The actual solar panels capture and transmit solar energy, which is then converted into usable power.
Floaters: These are interconnected plastic rafts on which the solar panels are mounted.
Mooring system – Anchors: These provide support from the water’s floor to solar panels floating on the water’s surface. Vertical load, drag embedded, and suction anchors are the most common types.
Mooring system. Mooring line: This is the line that connects the floaters on the solar panels to the anchor below. The mooring line’s strength is determined by the weight of the solar panels that must be supported.
Combine box: The output of all the solar panels on the array is collected in the combined box and fed to the central inverter.
Central inverter: The central inverter is a large component of the FPV that converts DC to AC for transmission.
Transformer: The transformer reduces the power to allow for easier transmission.
Cabling: Cabling is the wiring that connects the solar panels, combine box, central inverter, and transformer.
Transmission system: The transmission system is the inland connection line that transports power to where it is needed.
Floating walkways: The inland access point for the solar panels. When the solar panels need to be serviced, this is critical.
Features of Floating Solar
The solar module, anti-rust material, vertical and horizontal frames, buoyancy body, inspection footrest, and module mount assembly are the main components of a floating solar power plant. The solar module must be highly humidity resistant, dustproof, lead-free, and well-water-protected. The buoyancy is made of polyethylene, which can hold 2.5 times its weight. The floating structure is made of a magnesium alloy coating that is highly corrosion-resistant.
Advantages and Disadvantages of Floating Solar
Advantages of Floating Solar
There is no loss of valuable land space: Unlike ground-mounted solar panels, floating systems do not consume valuable land space. The large-scale installation of solar panels thus avoids cutting down trees.
Environmental advantages: They reduce water evaporation and algae blooms on water bodies’ surfaces. They produce clean, renewable energy while reducing reliance on nonrenewable fossil fuels.
Higher solar panel performance: Because the bodies of water that host floating solar arrays help cool the solar equipment, the panels produce electricity at a higher efficiency in hot climates than they would otherwise.
Disadvantages of Floating Solar
Expensive to Install: Installing them is more expensive than traditional PV systems because they require specialized equipment and knowledge.
Limited applicability: This technology is not suitable for everyone. Many floating solar installations are large-scale, supplying power to large communities, businesses, or utility companies. If you want solar, rooftop installation or ground-mounted solar is the better option.
Disruption to aquatic life: The installation prevents sunlight from penetrating the water’s surface, limiting the wildlife that lives there. Because the physical structure may injure animals, it is recommended that the panels be installed on man-made lakes and reservoirs with limited wildlife.
Maintenance of a Floating Solar Panel
Because water provides cooling, floating solar panels require little maintenance. Rainfall also aids in the cleaning process. The following measures are taken to clean and maintain solar panels.
Manual cleaning: For manual cleaning of floating solar panels, professional workers and appropriate materials should be selected. When selecting materials, extreme caution is required. This is due to the fact that certain cleaning chemicals can impair the performance of floating solar panels.
Sprinklers: In self-cleaning, both air and water can be used. Sprinklers are appropriate for arid climates. They simulate the cleaning effect of rainfall, allowing them to clean the panels at a low cost.
Forced airflow: Forced airflow from an air conditioner is also used for cleaning.
Robotic: Robotic maintenance techniques aid in the cleaning and repair of floating solar panels. Despite the high purchase price, it is also a cost-effective option that reduces water waste.
The Cost of Building a Floating Solar Power Plant
The cost of constructing a floating solar power plant will vary depending on the project’s size and location. Larger projects will generally be more expensive to build than smaller ones. The cost of land will also factor into the overall cost of the project. Floating solar power plants are typically constructed in sunny areas near large bodies of water, such as reservoirs. Building a floating solar power plant in an area with high winds and waves will be more expensive than in a calm location.
Aside from the cost of construction, the cost of maintaining a floating solar power plant must be considered. Repairs, replacement parts, and routine maintenance can all be included in these costs. When all of these costs are considered, the cost of constructing a floating solar power plant can be significant. The good news is that there are numerous advantages (including cost advantages) to be had throughout the lifespan of the floating solar plant.
Challenges of Setting up a Floating Solar Power Plant
In comparison to traditional ground-mounted and rooftop solar, the development of floating solar plants presents unique challenges due to hydrodynamic loads on the structure, corrosion risk, and additional components that must be designed, installed, and maintained, such as floats, anchors, and mooring lines. These difficulties are heavily influenced by the location, size, type of water body, structure, and environmental conditions. Doing a site-specific design and assessment will help floating solar projects, both new ones and ones that are already up and running, reduce risks.
As a result, establishing a floating solar plant necessitates careful planning and preparation. Once operational, however, an FPV can provide clean, efficient energy for the next 25 years.
Are Floating Solar Panels Efficient Than Land Solar Power Plants?
There is a lot of disagreement about whether floating solar panels are more efficient than solar power plants on land. Some argue that the water cools the solar panels, increasing their efficiency. Others argue that the water reduces the efficiency of the panels by reflecting sunlight away from them.
The truth is that both arguments are valid. Floating solar panels, on the other hand, have been shown in studies to be about 10% more efficient than land solar power plants. This is because the water cools the panels, allowing them to work more efficiently. The primary motivation for the owner to deploy an FPV system is to avoid occupying land and reduce water evaporation.
The Future of Floating Solar Farms
As the price of renewable energy continues to drop, the barriers to entry will also get lower. Current floating solar technology does necessitate a higher one-time installation cost. Nonetheless, when compared to its long-term effects on preventing energy leaks of up to 15%, at least during the solar panels’ 25-year lifespan, floating solar is actually more cost-effective, and arguably has advantages over ground-based solar.
Solar power is becoming a more affordable, accessible, and efficient energy source, and we must find creative ways to adapt its production to meet the diverse needs of people and the planet. Floating solar is unlikely to replace large-scale utility generation or the growing trend of terrestrial solar farms in the near future. However, it’s possible that they could play a crucial supplementary role, adding capacity where it currently lacks.
Conclusion
Floating solar is gaining popularity as a viable option for renewable energy generation. It’s a great option for people who want to use solar power but don’t have enough land for traditional solar panels. Contact us today if you want to learn more about floating solar systems or explore how they might work for you. We would be delighted to talk with you about this technology and answer any questions you may have.
Floating solar panels
Floating solar will make a significant contribution to the energy transition. Some scenarios predict 200 gigawatt peak (GWp) of solar power in the Netherlands in 2050, 25 GWp of which will be on inland waters and 45 GWp at sea. The knowledge level is still insufficient. For example, on the effect of wind and waves on solar panels and the lifetime of floating solar energy systems. Therefore, we are conducting plenty of research that fits with our mission to make solar energy applicable to different types of surface.
Wave Category 2
In 2017, together with partners from the National Consortium Solar on Water, we conducted a study on the feasibility of solar energy systems on water surfaces with wave category 2, waves until 1 meter high. This research took place at the Slufter on the Maasvlakte. The project provided a comprehensive inventory of challenges and potential failure mechanisms in these types of systems.
Performance of panels and ecological effects
The field lab located on the shores of the Oostvoornse Meer offers space for a variety of research projects on floating solar energy systems. At the field lab, floating solar energy systems are subjected to challenging conditions, such as wave category 2 and corrosive conditions. We are also researching the ecological impact of these systems on marine life and water quality.
An interesting line of thought is the construction of ring-shaped islands in the IJsselmeer, so-called atolls. This would allow us to create a lee area suitable for floating solar energy systems that can withstand wave category-2 conditions. This approach can go hand in hand with the required nature development (Natura 2000).
A next step is to use the surface of the IJsselmeer for solar energy. The IJsselmeer also has quite a substantial task in terms of nature development. The question is whether the development of new nature in the IJsselmeer region and solar energy can go hand in hand. Do we see opportunities for synergy on a spatial planning, policy, and/or financial level?
Offshore floating solar panels
In the North Sea, a large area has been earmarked for offshore renewable energy. Initially for wind energy, but there is enough space in between the wind turbines to generate solar energy as well. We are collaborating on several projects focused on how to achieve robust offshore floating solar energy systems with high yields and long service lives at acceptable costs.
Projects floating solar
We contribute to these projects from various areas of expertise and labs. Examples include solar energy components (modules and electronics) and complete systems, as well as new measurement methods to examine systems and components.
Oceans of Energy: research into offshore solar farm performance
The first floating pontoons from the Oceans of Energy company have now endured storms and high waves at a test site off the coast of Zeeland. A first step in demonstrating that offshore solar farms continue to function under severe weather conditions.
Oceans of Energy will build 1 megawatt (mWp) of offshore solar in the NS2 project, 12 km off the coast of Scheveningen. Partners are TNO, Deltares, NIOZ, WMR, TKF and Primo Marine. We’ll be researching the suitability of solar panels for offshore use, and are investigating integration at wind farms.
[email protected]: flexible floating solar panels at sea
Within the [email protected] project, Bluewater, Endures, Genap, Marin, TNO and Avans Hogeschool are working together at a concept based on a flexible structure. The basic idea here is to make the structure move optimally with the waves and to apply flexible solar panels. In this way, the consortium hopes to arrive at a robust solution that can withstand the forces of nature and achieves a high yield.
Crosswind: combination with offshore wind farm Hollandse Kust (Noord)
The CrossWind consortium, a joint venture of Shell in the Netherlands and Eneco, is building the new offshore wind farm Hollandse Kust (Noord). Together with CrossWind, we are working on research and a demonstration of solar energy at sea at this new offshore wind farm. The Hollandse Kust (Noord) offshore wind farm is expected to be operational in 2023. The offshore solar demonstration at this site will be 500 kWp in size and is planned for 2025.
SolarDuck: offshore prototype installation
In the Merganser project, we are collaborating with SolarDuck, Marin, Deltares and TU Delft. The consortium will develop, test and validate an offshore solar pilot installation under offshore (North Sea) weather conditions. The installation consists of 6 coupled platforms with a total capacity of 500 kWp. Through this project, the consortium aims to gain more insight into the suitability of the technology to operate under extreme offshore conditions. In addition, the partners are researching the ecological impact of such solar energy systems at sea and the incorporation of solar energy into offshore wind farms.
How do solar cells work underwater?
Although cells lose much of their power yield when submerged, they may not be useless. Researchers in India say submerged cells could be used in monitoring sensors and for other commercial and defense applications. An amorphous silicon cell from Panasonic was tested in their study.
The solar cell was submerged in four types of water.
Image: Birla Institute of Technology and Science, Pilani – Hyderabad Campus
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Researchers in India who tested the performance of an amorphous silicon solar cell underwater claim there could be potential applications for submerged devices.
Scientists at the Indian Institute of Technology Kanpur and the Birla Institute of Technology and Science, Pilani – Hyderabad Campus, said submerged cells benefit from lower temperatures and are in an ideal environment for cleaning.
Underwater devices obviously suffer lower solar radiation, however, citing another study the group said mono and polycrystalline cells would see a 20% fall in conversion efficiency at a depth of 1m but amorphous silicon devices showed less of a reduction at 1.5m, thus exhibiting potentially “stimulating outcomes”.
Ideal for small devices
The Kanpur and Hyderabad group said the remaining conversion efficiency could be sufficient to power submerged marine electronic devices.
The scientists tested an amorphous cell coated with polydimethylsiloxane (PDMS) – the most widely used silicon-based organic polymer for optoelectronic applications – at depths of up to 200cm. The PDMS has excellent optical properties and is hydrophobic, according to the researchers, who added: “It is inert, non-toxic and non-flammable.” The coating solution reportedly improved cell output by 2.79%.
The group opted for amorphous silicon cells as they have a spectral sensitivity to absorb light which is, essentially, in the visible wavelength range of 380-780nm. This makes amorphous cells ideal for underwater environments, where the spectrum narrows with an increase in depth and longer wavelengths penetrate at initial depths, the researchers said. Amorphous cells are also considered practical for indoor and outdoor environments.
Water types
The performance of the Panasonic cell tested was measured with an SS50AA solar simulator. The cell was submerged in four water environments: de-ionized water, lake water, seawater and artificial seawater prepared with commercially bought sea salt with 3.5% salinity and other water impurities.
The poorest performance was recorded in lake water, with bacteria, algae and other impurities reducing the transparency of the liquid.
The best power output – 0.0367 W – was recorded at a depth of 200cm in the de-ionized medium while figures of 0.0337 W and 0.0320 W were observed for the seawater and artificial equivalent, respectively.
“Although there are challenges and limitations, the results obtained show that there is an enormous potential for solar PV technology in underwater monitoring sensors or devices, and various other commercial and defense applications with modern-day power electronics,” the researchers wrote in the paper Analysing consequence of solar irradiance on amorphous silicon solar cell in variable underwater environments, published in the International Journal of Energy Research.
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Emiliano Bellini
Emiliano joined pv magazine in March 2017. He has been reporting on solar and renewable energy since 2009.