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EtaVolt develops technology to ‘rejuvenate’ solar panels…

03 Jan 2024

…and AI method identifies new way to spot dislocations in polycrystalline materials.

Using an innovative device that can energise old solar cells with multiple times the intensity of sunlight, scientists from EtaVolt, a spin-off from NTU Singapore (NTU) can rejuvenate old solar panels quickly and affordably. It can also protect both new and old solar panels from performance degradation caused by light and heat.

The underlying science behind this cutting-edge technology was developed at the Energy Research Institute @ NTU (ERI@N) and has been exclusively licensed to EtaVolt for commercialization and scale-up.

The start-up claims to offer a commercial solution to extend the operational lifespan of solar panels. Its statement says: “Our proprietary device is a game-changer in the solar energy industry, particularly in tropical regions like Singapore, where solar panels are subject to rapid deterioration due to constant exposure to intense sunlight, heat, humidity and frequent thunderstorms.”

Typically, solar panels can lose efficiency just hours after installation, especially in the first year as they face harsh environmental conditions. The drop in performance can be up to 10 per cent or more across the lifespan of the solar panels, says EtaVolt, “which translates to an estimated $2 billion in energy loss globally, based on the global 1 terawatt solar power capacity”.

The conventional method to maintain the performance of solar panels is to clean the top glass layer or to replace the entire solar panel module, but there is currently no commercially-available cost-effective way to easily restore its performance in the field or onsite, says EtaVolt.

Executive Director of ERI@N, Professor Madhavi Srinivasan, said the pursuit of sustainability through renewable energy will only make sense if the renewable energy systems themselves are sustainable and efficient.

“We have known for a long time that while harvesting sunlight gives us an almost inexhaustible source of energy, producing solar panels requires a lot of energy and generates a high carbon footprint. The reality is that solar panels in tropical countries face harsher conditions and there has been no real solution to restore and recycle the silicon cells,” said Prof Madhavi, who is also the Executive Director of NTU’s Sustainability Office.

He added, “Having a way to renew and eventually recycle solar panels is a key research programme at ERI@N, in addition to developing new renewable energy systems.”

Win-win for environment and industry

Co-founder of EtaVolt Dr Stanley Wang highlighted the benefit of the circular economy, emphasising that their patented technology not only enhances the efficiency and reliability of solar energy systems but also promises to reduce e-waste and the need for frequent panel replacements, making it a win-win for both the environment and the industry.

“Our solar rejuvenation method has not only been rigorously tested and validated but has shown field-proven results in various commercial applications. The technology has been successfully implemented in projects with major partners in the solar industry, such as renewable energy solutions firm Vector Green,” said Dr Wang, who is also a Project Manager at ERI@N.

Ben Teng, Managing Director of Vector Green, a Singapore sustainability and solar photovoltaic solutions company, said: “EtaVolt’s technologies for the assessment, regeneration, and recycling of PV systems provide solutions for our clients to enhance their investments through improved asset utilisation and performance. These efforts align with Vector Green’s goal of providing sustainable lifecycle solutions for the planet while unlocking profit value.”

Known as Advanced Regeneration Technology, the innovation by EtaVolt works for the majority of silicon solar cells in the market (over 90 per cent), including those that contain boron, oxygen, defects and other impurities. When intense light and controlled temperature are applied precisely to solar cells, they excite and cause the material molecules to move quickly, thereby changing their arrangement and patching up the ‘holes’ caused by light and heat damage.

The process repairs solar panels to prevent energy leakage, ensuring optimal light energy collection. The new device can automatically roll itself over solar panels that are up to 2.3 meters in length. The process takes less than five minutes and can help treated solar panels recover up to 5 per cent of their lost field performance.

It can prevent and minimise further degradation of the solar cells for up to five years, depending on the type of solar panels. It can also be used indoors and deployed on-site for outdoor solar farms. In addition to the solar panel rejuvenation services, EtaVolt also provides smart recycling services for solar panels with full automation, where they dismantle and recover useful materials.

AI identifies new way to spot flaws in polycrystalline materials

Researchers at Nagoya University, Japan, have used artificial intelligence to discover a new method for understanding defects called dislocations in polycrystalline materials. Such materials are widely used in solar cells, IT equipment, and other electronics. Dislocations can reduce the efficiency of such devices.

The discovery is described in Advanced Materials.

Despite the long-established use of devices based on polycrystalline materials, they remain difficult to work with because of their complex structures. The performance of a polycrystalline material is affected by its complex microstructure, dislocations, and impurities.

A major problem for using polycrystals is the formation of tiny crystal dislocations caused by stress and temperature changes. To reduce the chances of failure in devices that use polycrystalline materials, it is important to understand the formation of these dislocations.

The Nagoya researchers, led by Professor Noritaka Usami, employ a new AI approach to analyze image data of polycrystalline silicon, which is widely used in solar panels. The AI created a 3D model in virtual space, helping the team to identify the areas where dislocation clusters were affecting the material’s performance.

Prof. Usami commented, “We found a special nanostructure in the crystals associated with dislocations in polycrystalline structures. Along with its practical implications, this study may have important implications for the science of crystal growth and deformation as well.”

The Haasen-Alexander-Sumino (HAS) model is an influential theoretical framework used to understand the behavior of dislocations in materials. But Usami believes that they have discovered dislocations that the Haasen-Alexander-Sumino model missed.

Another surprise was to follow soon after, as when the team calculated the arrangement of the atoms in these structures, they found unexpectedly large tensile bond strains along the edge of the staircase-like structures that triggered dislocation generation.

Prof. Usami added, “As experts who have been studying this for years, we were amazed and excited to finally see proof of the presence of dislocations in these structures. It suggests that we can control the formation of dislocation clusters by controlling the direction in which the boundary spreads.”

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