An innovative saltwater-based flow battery system designed to store green power for weeks at a time has received backing from Norwegian power giant Statkraft.

Statkraft today (Tuesday) announced its partnership with Aquabattery, the Dutch start-up behind the design, at the COP28 climate summit in Dubai.

The new battery could “accelerate and revolutionise” long duration energy storage (LDES), claimed Statkraft CEO Christian Rynning-Tønnesen.

“Without the right mix of energy storage in the system, we risk slowing the pace of wind and solar rollout, and consequently the green transition.”

Large-scale energy storage systems, such as those using industry-standard lithium-ion batteries, typically only hold power for up to four hours.

But as countries sign up to triple global renewables capacity by 2030, Statkraft says that LDES – defined as storing energy for six hours or more – will be “pivotal” in creating a “sustainable and stable energy system” globally to support the green transition.

Aquabattery says it has designed its acid-base flow battery based on “reversible water dissociation.”

The battery stores electricity in the form of chemical energy in acid, base and saltwater solutions, which are kept in separate tanks. Pumps circulate these fluids through a power stack with electrodes separated by membranes. The membranes allow ion exchange between electrolytes to generate electricity.

The power output depends on the surface area of the electrodes, while the storage duration depends on the electrolyte volume.

Aquabattery says this makes flow batteries “easily customisable and suitable for long-duration applications and utility-scale deployment.”

The technology will be piloted in the Dutch city of Delft for between six to twelve months to “investigate the scalability” of the technology and its commercial viability, said Statkraft, which will provide financial backing and engineering know-how.

“Partnering with Statkraft is an important step to validate the unique value proposition of Aquabattery and de-risk the route to the solar and wind generation market,” said Jiajun Cen, CEO and co-founder of Aquabattery.

“Being a European climate tech innovator means creating not only a new alternative for Long Duration Energy Storage, but also a better alternative with regards to battery sustainability, safety and supply chain resilience,” he said.

“By using two of the world’s most abundant and cheap materials, table salt and water, Aquabattery is doing just that.”

Photo: Aquabattery