But currently less than 1% of the world’s solar installations are floating, says Michael Walls, a professor at the Centre for Renewable Energy Systems Technology at Loughborough University, in the UK. This is partly due to technical and financial constraints – saltwater causes corrosion and positioning panels at an angle is tricky and expensive on a floating platform, Walls says. Installations on freshwater bodies may also face opposition if they compete with other activities, such as swimming, boating or angling, he adds.
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Still, floating sun-powered farms also solve another problem plaguing conventional solar energy: inefficiency when solar panels become too hot. In fact, floating solar panels generate extra energy because of the cooling effect of the water they hover over.
Solar panels generate electricity using rays of light from the Sun – not its heat. But when they become too hot, their efficiency falls. This is because heat excites the panel’s electrons, which convert energy from the Sun into electricity, making the difference between the high energy and rest state smaller, which in turn decreases the voltage and the amount of electricity generated. Solar PV panels typically operate at peak efficiency between 15C and 35C (59F and 95F), but they can get as hot as 65C (149F), hindering efficiency.
The proximity to water of floating solar helps the panels operate more efficiently and increases their electricity production by up to 15%, says Nuno Correia, director of composite materials at the Institute of Science and Innovation in Mechanical and Industrial Engineering in Porto, who developed the Proteus project.
Follow the Sun
But there are also other ways to boost the energy production of solar panels – such as by tilting them to follow the Sun’s path in the sky, similar to the way young sunflowers follow the sun from east to west during the day. Tracking technology, which is already in use on some land based solar arrays, helps increase the overall electricity production, as the panels constantly adjust to face the Sun.
Double-sided panels that track the Sun could increase energy production by 35% and reduce the average cost of electricity by 16% compared to conventional systems, according to research by SERIS. Demand for tracking technology for solar panels is expected to grow by 16% per year between 2022 and 2030 due to this efficiency boost.
By merging the two technologies, SolarisFloat says it can increase electricity production by up to 40%, compared to static land installations.
SolarisFloat built Proteus as a pilot project, to test this cutting-edge technology and analyse how it boosts the generation of clean energy. The prototype landed them a position as a finalist for the European Inventor Award this year.
Proteus’ single-sidedpanels slowly rotate every few hours on two axes, using mechanical, geospatial and light sensors to precisely follow the elevation of the Sun’s path, as it moves from east to west.
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