The liquid metal battery system is meant to serve as an alternative to lithium-ion batteries, which degrade over time, and pumped-hydropower storage systems, which are reliant on the local geography. The battery is composed of calcium alloy and antimony separated by molten salt, allowing the batteries to operate at high temperatures as the calcium and salt liquify. This liquid-based system, Ambri says, reduces degradation compared to lithium-ion batteries and gives the battery a 20-year operating lifetime. The insulated battery system is self-heated and cycles daily.

Xcel Energy and Ambri will jointly test a 300-kWh system at SolarTAC in Aurora, Colorado, for 12 months, enabling an evaluation of its capabilities and performance. Installation of the system is expected to begin in early 2024, with the system fully operational later that year. The system will use the GridNXT Microgrid Platform at SolarTAC to integrate multiple generation sources, such as solar and wind, along with inverters, load banks, and 3-phase distribution connections and communications.

This collaboration is the first field-deployed utility pilot system for Ambri, showcasing its liquid metal batteries in a real-world setting. It also marks the initial evaluation and demonstration of these batteries by a major U.S. utility. Throughout the demonstration period, Xcel Energy and Ambri will test various use cases, including solar and wind integration, capacity management, arbitrage, and ancillary services, among others.

In 2021, Ambri announced a $144 million financing round, backed by India’s Reliance New Energy Solar Ltd, Paulson & Co. Inc, and the company’s largest shareholder, Bill Gates. Those funds were intended to be used for financing and commercializing Ambri’s daily cycling, long-duration system technology and to build a domestic manufacturing facility, the company said.

Xcel Energy, provider of electricity and natural gas services to nearly 6 million customers in eight Western and Midwestern states, has committed to achieve net-zero greenhouse gas emissions from its natural gas business by 2050.

The announcement Monday comes nearly three years after the utility pledged to deliver 100% carbon-free electricity to customers by 2050, with an interim target of reducing emissions by 80% by 2030.

Xcel will now accelerate plans to reduce methane emissions by, in part, purchasing natural gas only from suppliers with "certified low emissions" and continuing to improve its gas delivery system. The company will also expand customer programs for the adoption of electric appliances and low-carbon gas alternatives.

“Earlier this year, Colorado released our roadmap for 100% clean electricity generation by 2040, cleaner air, and bold climate action,” said Colorado Gov. Jared Polis. “This exciting new commitment by Xcel Energy represents a major step forward that will support Colorado in achieving our state’s climate goals and illustrates how Colorado is encouraging the innovation and collaboration needed to foster a clean economy. Xcel Energy’s aggressive, forward looking plans for clean energy are welcomed news."

Xcel will also launch a series of pilot programs to test renewable natural gas, smart electric water heaters, and air source heat pumps with customers, as well as testing hydrogen production and hydrogen blending in its natural gas system.

A study by the Center on Global Energy Policy at Columbia University advocated for investments in the U.S. natural gas pipeline system to support the eventual shift from natural gas to cleaner, low-to-no carbon fuels. Not for several more decades will zero-carbon fuels be ready to replace natural gas as the backbone of the energy mix, the authors wrote, and pipeline upgrades can support the transportation of hydrogen and biogas.

RMI commended Xcel's desire to expand its net-zero target to its natural gas business.

"RMI supports Xcel Energy’s desire to reduce its methane intensity by sourcing certified natural gas from transparent, independent certification programs such as MiQ, and carefully monitoring methane emissions in its distribution system. RMI will continue to work with regulators to ensure that utilities can appropriately recover costs for delivering gas with a lower climate impact to their consumers," Lara Owens, manager of climate intelligence at RMI, said in a statement.

Xcel expects the net-zero targets to reduce nearly 80 million tons of carbon by 2030.