US sodium-ion (Na-ion) battery startup Alsym Energy and California-based renewables developer Juniper Energy have announced a 500MWh strategic partnership.
Announced 12 May, the partnership sees Alsym deploying 500MWh of its Na-ion battery energy storage system (BESS) solution across California, US.
According to the companies, a “cornerstone” of the partnership is Alsym’s deployment of its batteries in the Mojave Desert, and other high-temperature regions.
Speaking with Energy-Storage.news Premium in November 2025, Alsym CEO, president, and co-founder, Mukesh Chatter, stated, “Na-ion can comfortably operate at ambient temperatures up to 50 degrees Celsius. In hot climates like California or Texas, once temperatures reach around 43 degrees Celsius, you need to shut lithium iron phosphate (LFP) systems down because it’s too hot. Since it’s based on LFP technology, during the times you need it most, such as in extreme heat, you’ll actually have the least performance.”
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He additionally noted, “We will also have the UL9540A certification at the cell level, which LFP cannot achieve. This underscores the focus on non-flammability, non-toxicity, cost competitiveness, and an extended temperature range.”
According to Alsym, the partnership with Juniper leverages the technology’s passive cooling feature, which reduces balance of plant (BoP) complexity, lowers initial capital costs, and decreases ongoing operations & maintenance (O&M) expenses.
The technology’s high charge and discharge rates allow for multiple daily cycles, enabling both revenue generation and load shifting. The extended cycle life maintains these operational capabilities, theoretically without early degradation or the need for system augmentation.
Juniper and Alsym also highlight that the partnership is designed to “maximise the financial attractiveness of renewable projects”, utilising domestically manufactured cells from Alsym.
Juniper Energy plans to take advantage of the investment tax credit (ITC) and other US Department of Energy (DOE) incentives.
This announcement builds on the 30 April news that iron flow battery company ESS Tech Inc signed a letter of intent for a strategic partnership with Alsym.
That partnership will see ESS Tech add 8.5GWh of Alsym’s Na-ion cells and modules to its portfolio, and mark long-duration energy storage (LDES) tech company ESS’ entry into the short and medium-duration BESS segment.
Juniper Energy’s website does not contain much information about the company itself. The company’s founder and managing partner is Keith McDaniels, who was previously an attorney at corporate bankruptcy, restructuring, and crisis management law firm Keller Benevenutti LLP.
There also exists a July 2025 document from the San Bernadino County, California Land Use Services Department Planning Commission, detailing a proposal for a conditional use permit for Juniper Energy to construct and operate an 8MW solar PV facility, paired with BESS.
