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Revolutionary saltwater battery tested in Delft
By: André Oerlemans

The revolutionary saltwater battery from the Dutch Aquabattery will be tested next year at Deltares in Delft. Both organizations announced this during the climate summit in Dubai. The Dutch start-up will collaborate with sustainable energy company Statkraft on this pilot. It wants to investigate whether this battery can store green energy from its wind and solar parks for a long time.
Now that more solar and wind energy is being generated - nowadays half of all electricity - that power must be stored for a long time to bridge periods without wind and sun. The so-called Dunkelflaute. This is called Long Duration Energy Storage (LDES). This is becoming increasingly important worldwide for a renewable energy system without CO2 emissions and without fossil fuels.

Flow batteries important
Long-term storage is not possible with lithium-ion batteries. These can store the green energy for a maximum of four to six hours and are relatively expensive. In addition, the extraction of lithium causes a lot of environmental pollution. That is why work is being done all over the world to develop flow batteries, where electricity is stored in liquids for a long time. The founders of Aquabattery, including current CEO Jiajun Cen and COO Emil Goosen, investigated how you can store electricity in a saltwater battery during their PhD research. They started their company in 2014, held their first pilot a few years later and are now ready to further scale up the technology in practice. “We store electricity in water and table salt. What we are developing is large-scale long-term energy storage,” says their CCO Janneke Tjon Pian Gi – Stuijfzand.

Store power easily and endlessly
Aquabattery makes saltwater with that water and table salt. This is stored in a tank that is part of the battery. Using excess wind or solar energy, the saltwater is pumped through membrane stacks. These membranes split that salty water into an acid and a base solution, the so-called electrolytes. Those two solutions are stored separately in two other tanks of the battery. The electricity is then, as it were, stored in those two water solutions. When electricity needs to be extracted from the battery, the acid and base are brought together via the same membrane stacks and saltwater is created. During that process, electricity is generated so that the battery discharges again. The salt water can be split again, so that the process can be repeated endlessly. Although the operation of the battery seems as simple as Columbus's Egg, Aquabattery is the only one to have patented this technology.

Secure, cheap and scalable
The battery can store electricity for at least eight hours, but also for several days or weeks if necessary. The storage capacity can also be easily expanded by adding more or larger tanks for salt water, acid and base solutions. The battery is safe, cheap, scalable and does not require scarce raw materials. After all, water and table salt are widely available. The start-up was included in the MT/Sprout Challenger50 last month and won the 'Innovative Energy Solutions Award 2023' during the Energy Trade Fair in Den Bosch.
Practice test
Whether the battery works as well in practice as in the lab will be tested after the summer next year on the campus of the Deltares knowledge institute in Delft. Both companies announced this during the COP28 climate summit in Dubai. The pilot will last six to twelve months. Battery technology is being scaled up and validated in Delft. “Our technology is still developing. We want to take steps next year to make the technology commercially available to the market,” says Tjon Pian Gi. “For this purpose, it is important to place the battery in the real world to see, for example, how it responds to temperature fluctuations, how it deals with permits and what possible impact it has on the environment.”

Storing power from solar panels
In Delft, the battery will store excess solar energy from Deltares' 5,725 panels during the day and supply it back when the sun is not shining. By applying long-term energy storage at scale, Deltares computers and servers can run on green energy 24/7. The pilot installation can store 10 hours of power and the battery power is five to ten times more than the current pilot setup. “This is an exciting step. If we can make this, the step to five to ten times bigger again will be a lot easier. That is a matter of repeating the trick,” says Tjon Pian Gi.

Storing power from solar parks
In the pilot, Aqua Battery is working with Statkraft, an originally Norwegian state-owned company that has been active in the Netherlands for 25 years and develops solar and wind farms. Both companies also announced this during COP28. The company supports the pilot financially and contributes its extensive knowledge and experience. Statkraft has now built thirteen solar parks in the Netherlands and two are under construction. The energy company is also considering long-term storage of green energy and is investigating which batteries are most suitable for this. “To take the next step in the Dutch energy transition, we must be able to bridge longer periods without wind and sun. We see Aquabattery as one of the solutions for this, precisely because it has a sustainable component,” says Valerie van Hagen, Head of New Business at Statkraft Netherlands.


  • Munene Mugambi

    18 w

    I'm very optimistic on this project and I'd love to see a successful test conducted and us adopting this battery

    • Rukia Ahmed Abdi

      18 w

      This article highlights a breakthrough in energy storage technology with the development of a revolutionary saltwater battery by Dutch startup Aquabattery. The battery, set to be tested at Deltares in Delft, aims to address the challenges of long-duration energy storage, crucial for harnessing solar and wind energy efficiently. Unlike lithium-ion batteries, the saltwater battery can store electricity for at least eight hours and is scalable, cheap, and environmentally friendly. The upcoming pilot, in collaboration with sustainable energy company Statkraft, will assess the battery's real-world performance, emphasizing its potential role in the transition to a renewable energy system. The innovative solution could play a significant role in storing excess solar energy, contributing to a sustainable energy future.

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