RWE, a leading German energy company, is testing NASA-developed nickel-hydrogen batteries, called Energy Storage Vessels (ESVs), in a renewable energy pilot at its Milwaukee facility. Supplied by EnerVenue, these batteries offer exceptional durability, lasting over 30,000 cycles or up to 30 years.
The global shift toward renewable energy demands innovative storage solutions. While lithium-ion batteries dominate the market, scaling them for large projects is increasingly expensive and complex. Nickel-hydrogen batteries offer a safer and more durable alternative. Unlike lithium-ion batteries, they avoid risks like thermal runaway, reducing the need for extensive cooling and fire suppression systems.
Nickel-hydrogen batteries operate similarly to traditional batteries with stacked electrodes, but their design includes a pressurized gas tank. Nickel hydroxide serves as the cathode, and hydrogen functions as the anode. During charging, hydrogen gas is produced, which is oxidized to water during discharge.
Safety concerns are mitigated by the low internal pressure—just 5% of that in hydrogen fuel cells—and the system’s ability to recombine excess hydrogen into water, ensuring reliability.
NASA has employed nickel-hydrogen batteries in critical systems like the International Space Station since the 1970s. Initially reliant on expensive platinum catalysts, the technology became more accessible in 2020 thanks to a breakthrough by Stanford professor Yi Cui. He developed a nickel-molybdenum-cobalt alloy catalyst, enabling cost-efficient production and widespread adoption.
EnerVenue’s ESVs, derived from this innovation, are designed for large-scale applications. Each six-foot-long tank stores 3 kWh of energy and operates across temperatures from -40°F to 140°F without requiring added safety infrastructure. Although their energy density is lower than lithium-ion batteries, their unmatched durability and operational lifespan make them an attractive choice for sustainable energy systems.
RWE’s Milwaukee pilot project aims to test the efficiency, temperature resilience, cycling performance, and overall adaptability of ESV batteries. The company is using this initiative to gather data that could guide the integration of nickel-hydrogen batteries into broader energy projects.
These batteries also align with sustainability goals, offering a scalable, recyclable solution that minimizes environmental impact while avoiding the fire risks associated with lithium-ion alternatives.
“Energy Storage Vessels are built to meet the demands of even the most diverse and challenging clean energy applications,” said Majid Keshavarz, CTO of EnerVenue. “Collaborating with RWE allows us to showcase the capabilities of our technology and its potential to drive clean energy expansion and grid resilience.”
RWE already operates battery storage systems across the U.S., Europe, and Australia, with 0.7 GW of capacity in operation and 1.4 GW under construction. As part of its Growing Green strategy, the company aims to achieve a global capacity of 6 GW by 2030, reinforcing its leadership in renewable energy storage.