Rhubarb usually used in cooking may be gaining another role. An Italian-led consortium believes it could also hold the key to producing organic batteries. Green Energy Storage developed a 2.5 kW/10 kWh battery made from quinones – molecules produced during photosynthesis in plants like rhubarb – and successfully tested four of them in a grid system on project GREENERNET. “This is a semi-organic flow battery. It creates less pollution than standard lithium iron phosphate batteries,” said Adele Vitale, Internal Process Manager and Project Manager of Green Energy Storage (GES), which coordinated the project. “Quinones are found in different plants and are a natural way the plants have of storing energy. We use plants like rhubarb to create a solution rich in electrolytes, the molecules that store electric charges.” The GREENERNET battery is cheaper to produce than the lithium phosphate battery being sold by competitors, currently retailing at about €470/kWh. It also has lower maintenance costs when used in a grid system, can be used in a modular way and has a longer life cycle. GES first tested the qualities of rhubarb five years ago when it developed an early 1kW prototype with researchers on another project. The researchers had seized on the use of quinones tested at Harvard University. Using abundant quinones in batteries, rather than toxic metals, was much better for the environment. GES obtained the European licence from Harvard for the technology. Moving to market During two-and-a-half year project GREENERNET, GES and the consortium partners developed a more powerful 10 kW battery and a battery management system to connect the batteries together, allowing for the storage of energy, taking into account the charge and discharge cycles of the batteries to optimise the whole system. While GES provided the flow battery knowledge, Rome-based Engineering provided expertise in the software needed for the grid and Budapest-based Evopro Innovation provided hardware components. The University of Rome Tor Vergata and Aarhus University in Denmark carried out all the laboratory tests needed. “This involved a huge amount of technological know-how,” said Ms Vitale. “GES couldn’t have developed the microgrid system alone.” GES says the battery system could be used in a number of scenarios, including to power electrical vehicle power stations, potentially cutting the cost of running an electrical car. Their system could also be used to provide some of the energy in homes when electricity produced from other sources is expensive. The partners have not yet commercialised the system yet, but they have sold two pre-commercial units to major utility companies. That has helped them grow revenues, and they see the consortium hitting the revenue target it set itself of EUR 70 million by early next year. GES has made the important transition from being a start-up to a more consolidated company and has opened a new production site in Rovereto. As European countries strive to cut their carbon footprint, there is growing demand for more renewables solutions in housing, the car and other industries. “Our reliable and efficient storage system is really well-placed to meet that need,” said Ms Vitale.
GREENERNET, rhubarb, organic batteries, quinones, green energy, semi-organic flow battery