Tech Insights

Xcel Energy, Ambri Team Up for World-First Grid Deployment of Liquid Metal Batteries

August 30, 2023 by Jake Hertz

This collaboration marks a significant milestone in the commercialization of liquid metal batteries.

Facilitating the widespread, mainstream adoption of renewable energy necessitates powerful new forms of energy storage. While many chemistries and technologies have been proposed, one with a unique amount of promise is that of liquid metal batteries. 

Ambri’s solution is used to store energy from renewable sources and supply that stored energy to the grid at large

Ambri’s solution is used to store energy from renewable sources and supply that stored energy to the grid at large. Image used courtesy of Ambri

After years of being relegated to academia and the lab, liquid metal is now finally ready to make its introduction into the real world. Xcel Energy’s SolarTAC will use Ambri liquid metal batteries in a year-long trial.


Ambri and Xcel Team Up

Ambri, a company known for its patented liquid metal battery technology, has signed its first agreement with a utility provider, Xcel Energy, to bring its technology to the grid.

The collaboration will involve a 12-month joint testing of a 300 kWh renewable energy system at SolarTAC (Solar Technology Acceleration Center) in Aurora, Colorado. Specifically, the system will integrate multiple generation sources like solar and wind, using the GridNXT Microgrid Platform, which is a plug-and-play microgrid platform for testing new technologies. Within the Microgrid, Ambri’s liquid metal battery will be used to facilitate the storage of energy from intermittent renewable sources.

The installation, which is expected to begin in early 2024, marks the world’s first deployment of a liquid metal battery in a real-world environment. The demonstration will explore various use cases, including solar and wind integration, capacity management, arbitrage, and ancillary services.


Liquid Metal: A Look at the Tech

Liquid metal battery technology represents a significant advancement in energy storage. 

In general, a liquid metal battery consists of three layers: two liquid metal electrodes separated by a molten salt electrolyte. Notably, there is no membrane or separator in these batteries, ins tad these layers naturally settle into distinct strata due to their differing densities and immiscibility. In Ambri’s battery, the top layer is a low-density liquid metal calcium alloy, sodium, the middle layer is a CaCl2 molten salt electrolyte, and the bottom layer consists of high-density antimony particles.


The chemistry and charging cycle of Ambri’s liquid metal battery

The chemistry and charging cycle of Ambri’s liquid metal battery. Image used courtesy of Ambri


During charging, electrons are removed from the low-density metal (anode), causing it to oxidize and dissolve into the molten salt layer. Simultaneously, the high-density metal (cathode) is reduced, and the corresponding metal cations in the salt layer are plated onto it.

During discharging, the process is reversed. Electrons flow back to the anode, reducing the metal cations in the salt layer, and the metal is plated back onto the anode. Meanwhile, the cathode is oxidized, and the metal dissolves into the salt.

Notably, the entire system needs to operate at elevated temperatures (around 500°C) to keep the metals and salt in a liquid state. 


Liquid Metal Benefits

According to Ambri, liquid metal battery technology offers a number of key benefits over competing energy storage systems. These include:

  • Lower cost: Ambri's liquid metal battery technology utilizes abundant and low-cost materials, reducing the overall cost of the battery. The simple design and manufacturing process further contribute to cost savings.
  • Long life: The liquid state of the battery components minimizes wear and tear, potentially leading to a longer lifespan. This makes it suitable for applications requiring long-duration energy storage, such as grid support.
  • Modular design: The scalability of Ambri's technology allows for modular design, enabling customization to various energy storage needs. This flexibility can cater to different applications, from small-scale residential to large-scale industrial use.
  • Recyclable: The use of abundant and non-toxic materials in Ambri's batteries may facilitate recycling, aligning with sustainability goals and reducing environmental impact.


Reaching the Grid

No doubt, the collaboration between Xcel and Ambri marks a huge milestone for the energy storage industry. Barring the success of the Ambri trial, Xcel plans to develop a follow-on plan for larger-capacity long-duration energy storage projects.