Floating solar farm mooring system that tracks the sun: Nuno Correia and Carla Gomes named finalists for European Inventor Award 2022

The European Patent Office (EPO) announced that Portuguese engineers Nuno Correia and Carla Gomes have been nominated for the European Inventor Award 2022 for their mooring system for floating solar farms that tracks the sun by rotating the island and tilting its photovoltaic panels. 

The dynamic nature of their floating solar farm system makes it possible to maximise the solar energy captured and increase panel efficiency by up to 40% compared to stationary solutions. With the global shift towards carbon neutrality, interest in floating solar farms is growing because they don’t take up land that could be used to grow crops, which is becoming scarce worldwide due to factors such as pollution and erosion.

"Nuno Correia and Cara Gomes have come up with a solution that improves the production of solar energy,” says EPO President António Campinos, announcing the European Inventor Award 2022 finalists. "Their invention is an excellent example of technology that can help reduce our dependency on fossil fuels and improve the sustainable use of land resources, while also encouraging investment in renewable energy on a larger scale.”  

Correia and Gomes, who developed the invention at the Institute of Science and Innovation in Mechanical and Industrial Engineering (INEGI) in Porto, are jointly named as one of four finalists in the "SMEs” category, which recognises exceptional inventors in small companies with fewer than 250 employees and an annual turnover of less than EUR 50 million. The winners of the 2022 edition of the EPO’s European Inventor Award will be announced at a virtual ceremony on 21 June. 

Correia, Gomes and the team at INEGI were contracted by Portuguese company SolarisFloat to develop a floating system of photovoltaic panels that can track the sun to produce more solar power. On land, industrial solar panels can be mounted on systems that allow the panels to turn towards the sun, but the same approach is more difficult to implement on water and so far has only been attempted in a few floating designs. 

The system developed by Correia and Gomes, called PROTEVS, operates autonomously using an onboard control system. It contains 180 photovoltaic panels in a circular "island” of about 38 metres in diameter, which rotates at a slow pace around a central point powered by electric motors. The system turns in one direction during the day, following the sun, and in the opposite direction at night to return it to its original position. The panels themselves can also be tilted depending on the sun’s position. 

The system is designed to be used in relatively calm water bodies such as lakes and reservoirs. To accommodate changes in water levels, the island of panels is fixed in place by an outer ring moored with cables and anchors of a flexible length so it can move up and down by up to 20 or 30 metres. It’s also designed to be long-lasting and built to resist a variety of environmental conditions, such as saline water and waves up to one-metre high. Made from 100% recycled materials, it can also be recycled after use. 

Installing PV systems on water can improve their efficiency by up to 15% compared to when installed on land, since water-cooled air keeps the panels at a lower temperature and ensures they’re operating efficiently. "Having these systems on water means that we’re not occupying arable land with the production of photovoltaic energy,” says Correia. "That’s important if we're trying to produce a large amount of energy in renewables.”

While developing their system, the team carried out an environmental analysis and found additional benefits. By creating shadows and acting as a wind-break, the platform lowers the water temperature and reduces evaporation of the water body by up to 60%. Colder water can hold more dissolved oxygen than warmer water, which helps aquatic organisms to flourish and reduces the ability of algae to grow on the surface. Limiting evaporation can also help mitigate water shortages – a concern in many countries such as Portugal where there is a lack of rainfall due to global warming.

The effects of PROTEVS on local ecosystems is now being further evaluated in a pilot project with a consortium led by the Netherlands Organisation for Applied Scientific Research (TNO). 

SolarisFloat outsourced the development of PROTEVS to INEGI in order to speed up the research and development. While Correia, Gomes and the team are named on the patent, it is owned by SolarisFloat, who will now market the product. Correia says the patent was instrumental in getting the system off the ground. "In this field, I don’t think anyone would have put in the money as they did without a patent,” he says.

The biggest market for the system is in Europe, with partners also in India and potentially in South America. Brazil is home to some of the world’s largest reservoirs, which are currently used for hydropower, but floating solar power plants could supply 80% of the country’s energy if they were to cover 8% of the area in 165 large reservoirs. SolarisFloat is also considering developing an offshore solution in the near future. The market for floating solar panels is expected to grow by more than 24 % between 2022 and 2030.