Researchers in Sardinia have made remarkable advances in sustainable energy by developing Sodium-Seawater Batteries for Short and Long-Term Stationary Energy Storage. They discovered SWBs can efficiently store energy and stabilize power fluctuations by using sodium-biphenyl technology combined with wave energy. This new discovery is expected to fulfil Sardinia’s energy and water requirements while also capturing carbon dioxide. This is a significant step forward in the transition to clean energy for coastal areas and islands.
Researchers from the University of Perugia and the Sapienza University of Rome have conducted a study on the promising capabilities of SWBs. Their research revolves around a case study on the renewable energy abundance of Sardinia Island.
Their findings revealed that SWBs, combined with wave energy, can effectively stabilize power fluctuations and pave the way for a completely decarbonized power generation system in the long term. Sodium-based battery technology known as SWBs shows great efficiency, utilizing seawater as the cathode. One of the many advantages of SWBs is their remarkable ability to store energy effectively for both short and long periods, ensuring reliable annual energy storage.
To harness this potential, they used sodium-biphenyl (Na-BP) as the anolyte, creating a remarkable SWB technology. This innovative design allows both the anolyte and catholyte (seawater) to flow through the battery cells, resembling a conventional redox flow battery with remarkable efficiency.
Researchers have revealed that one of the major advantages of Na-BP-based SWBs is the ability to store metallic sodium externally. By expanding the reservoir of Na metal, this innovative feature greatly enhances the storage duration. As a result, it becomes feasible to store energy from hour to month, or even throughout the seasons, using just a single device. It not only enhances overall efficiency but also reduces investment expenses.
Researchers said, â€œThis work aims at demonstrating the applicability of SWB to meet the European energy requirements, to arise the interest of the public and private sectors in the further development needed to bring the laboratory scale cells so far developed into commercial applications.â€
In order to achieve this objective, the researchers explored the use of SWBs in conjunction with wave energy converters. Their investigation revealed that this combination could potentially decrease power fluctuations on the Sardinian grid by over 85%. Specifically, they calculated the reduction in power ramp up by comparing consecutive power values at one-second intervals. Furthermore, they stored the energy in the Na-BP anolyte.
The researchers concluded that in the long-term perspective, SWBs have the potential to meet Sardinia’s seasonal and yearly energy requirements. This is due to the remarkably high volumetric densities of Na metal, which is about four times greater than compressed hydrogen at 700 bars.
To achieve full decarbonization of the Sardinian grid, the integration of approximately 340,000 m3 of Na metal is necessary. This amount is equivalent to a Na reservoir that is 12 meters in height and covers a surface area of less than four soccer fields, as calculated by the researchers.
Furthermore, sodium-seawater batteries for short and long-term stationary energy storage have the potential to fulfil approximately 29% of the Sardinian population’s desalinated water needs. Not only that, but it also possesses a supplementary carbon-dioxide capture function, effectively storing 37.3 grams of CO2 per kWh.
Researchers mentioned in the report that, â€œThe results of the modeling demonstrate the effectiveness of SWB-based energy storage combined with the abundant renewable sources of Sardinia, enabling the full decarbonization of the energy system on the island. Moreover, SWBs desalination and CO2 capture functionalities is an exemplar of clean energy transition implementation that can be extended to other islands and coastal areas.â€