Floating Solar Panels Could Provide Over A Third Of Global Electricity

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Over the past decade, the cost of solar power has dropped dramatically, making it the cheapest source of electricity in most parts of the world. Obviously, this could mean cheaper energy. But it also means we can place panels where it would be too expensive and still produce profitable energy.

One of the most interesting options is the installation of panels on artificial reservoirs that float or hang on cables. Although it is more expensive than ground installation, it creates a win-win situation. the modules limit water evaporation and the water cools the modules allowing them to work more efficiently in hot climates.

Although the potential of Floating Solar has been explored in several places, a group of researchers did a global analysis and found it to be huge. Even if we limit installations to a small fraction of the surface area of ​​existing bodies of water, floating panels can generate almost 10,000 terawatt-hours per year, saving more than 100 cubic kilometers of water from evaporation.

Going global

The international team of researchers behind the new work admit they are far from the first to explore the potential of floating solar power. However, most previous analyzes have been limited to a single country or reservoir system. The new work is unique in that it is global in nature and uses the most advanced model of photovoltaic cells in various environmental conditions developed by the Sandia National Laboratory of the US Department of Energy. The team also obtained data on temperature, solar radiation and wind speed over two decades from two different Earth observation satellite systems.

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The researchers note that tank-floating solar panels have a number of benefits beyond cooling the panels and reducing water loss. First, you don't sacrifice untouched land to cover it with slabs because humanity has already flooded that land. While the panels block light from entering the water and can create problems for any ecosystem growing there, they can also help reduce harmful algal blooms in the water supply.

Another advantage is that many reservoirs are located close to energy-intensive metropolitan areas and the networks that feed them, making it easy to use the energy produced there. Finally, many reservoirs are connected to hydroelectric power plants, and the two energy sources can work as one to maintain stable production levels 24/7 and in all weather conditions.

To preserve reservoir ecosystems and allow reservoirs to be used for recreational purposes, the researchers limited the area covered by slabs to a maximum of 30 percent of their surface or 30 square kilometers, whichever is less (30/30 limit).

i feel strong

The amount of electricity that can be generated worldwide is about 9,400 TWh per year. In comparison, global electricity consumption is around 22,800 TWh, which means that floating solar panels can meet more than 40 percent of the world's electricity demand. A 10% reduction in storage coverage, a very significant reduction, could still produce 4,300 TWh.

It is clear that this potential is unevenly distributed, with countries like Canada and the Nordic countries receiving less sunlight to benefit. The biggest winner from Floating Solar will be the United States, which has 1,900 TWh of capacity under 30/30 limits. The United States consumes about 3,900 TWh per year, which is almost half of its electricity consumption. Existing renewables and nuclear made up about 40 percent of our energy mix last year, so if we can manage the necessary storage it will go a long way to decarbonize the grid.

The other 10 countries with floating solar potential are China, Brazil, India, Canada, Russia, Mexico, Australia, Turkey and South Africa. Obviously, this list includes a number of countries that can make a big contribution to decarbonization. So far, only three of them (Brazil, China and India) have significant floating solar capacity.

The researchers also calculated that 40 countries could fully meet their current energy needs with floating solar power, although the storage problem remains. While many of these countries are small and still have emerging economies, the list includes Brazil in particular, which has a large economy and energy needs. The analysis also shows that there are about 150 cities with a population of more than 1 million people that can fully satisfy their electricity needs with solar energy from nearby water bodies.

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fight the heat

When it comes to saving water, panels make a much bigger impact than their 30 percent coverage. This is because they lower the temperature of the water and not just block out the sun's rays. This reduces evaporation by about 45 percent. The total reduced evaporation adds about 100 km3 of water per year, which, according to the authors, is enough to meet the needs of about 300 million people.

In particular, they point to countries with high population densities and water scarcity that could benefit, such as Egypt and South Africa. They calculated that the latter could generate 144% of the annual 205 TWh of electricity from a floating solar panel and avoid losing 1.6 cubic kilometers of water to evaporation.

All this, in turn, will be more expensive than just installing modules on the ground, since many years of experience have significantly reduced the cost of building solar power plants. Again, there is a performance trade-off. Nearly all ground panels today do their job of tracking the sun's movement across the sky. With a floating system, this would be much more difficult, and tilting the panels would likely result in significant evaporation.

These additional costs are offset by hard-to-measure things, such as ensuring adequate water supply for a large number of users and limiting development on previously uninhabited areas. Costs and uncertainties must be accounted for to ensure that floating solar is more than just a bug; It is expected that 5 gigawatts of installed capacity worldwide will be decommissioned no earlier than 2027. And this year alone, the US is likely to deploy almost six times as much capacity.

Nature Sustainability , 2023. DOI: 10.1038/s41893-023-01089-6 (via DOI).

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