The renewable energy arm of Italian energy company Enel SpA is researching the application of graphene as a material to boost the efficiency of solar cells under a European Union (EU) backed project called Graphene Integrated Perovskite Silicon Tandem Solar Cells (GRAPES).
Enel Green Power (EGP) said its senior executive Marina Foti has been appointed to lead GRAPES. The EU is investing €1 billion on Core 3 Spearhead Project Grapes, part of the Graphene Flagship project, said the Italian company.
Foti describes graphene as having the theoretical strength of a diamond and flexibility of plastic to integrate silicon and perovskite cells. "Silicon cells have at a theoretical efficiency limit of 29% and a practical one of 26% to 27%," said Foti. Experiments are now being carried out for tandem or multijunction cells to exceed the limits on this efficiency level, and under Foti the EU research will focus on use of graphene as an intermediate layer between silicon and perovskite cells to improve tandem cell efficiency.
"The challenge is to take a quite unstable material to the industrial phase, while being aware that a panel has to maintain the same performance levels for 30 years," said Foti.
Graphene has also attracted attention from several PV companies for its promise of being a lower cost possible replacement for the use of silver in solar cells. Fellow Italian manufacturer Verditek is working with Cambridge University subsidiary Paragraf to commercialize graphene integrated PV cells (see Verditek To Raise £2Mn For Italian Module Fab).
In August 2020, Chinese solar module maker Zhengxin Optoelectronics announced capacity expansion and said it plans to use its own patented graphene coating technology for another job – enhancing the self-cleaning ability of a module (see China PV News Snippets: Sungrow, Arctech Solar).
In February 2020, researchers from Italian university Tor Vergata and ENEA achieved 26.3% perovskite and silicon tandem solar cell efficiency using graphene-doped mesoporous electron selective layer (see Italian Researchers Claim 26.3% Efficiency For Tandem PV Cell).
Floating solar technology
Separately EGP also said it is dabbling with floating solar PV technology and has deployed a 30 kW solar array on a water body in Catania, Italy at its Innovation Lab. This pilot will enable EGP to understand performance of a floating PV project for wider application on various water bodies.
For its research, EGP has integrated both monofacial and bifacial modules into the same platform to test different operating conditions of the 30 kW system and compare its performance with ground mounted solar power plants. It believes the technology carries a lot of potential in terms of saving land use, improving module efficiency, saving water from evaporation, but it needs to be thoroughly researched to exploit full benefit of the technology.
EGP said it is working alongside the US government's National Renewable Energy Laboratory (NREL) studying 4 floating solar plants in the US for a period of 3 years to fathom the impact of these installations on the aquatic environment and on biodiversity.
Data collected will encourage design improvement and optimize construction phases of new floating PV projects across the globe.
Notably, a recent NREL research on floating solar technology pegged 7.6 TW annual solar power production potential from these panels when deployed on hydropower water bodies thereby lowering costs (see 7.6 TW Power From Floating PV On Hydropower Bodies).
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