This medium releases 99.99 percent pure hydrogen, which could power electrical grids, hydrogen fuel cells, cars, or hydrogen-injected diesel trucks.
Former computer-chip manufacturing engineer Paul Smith founded Plasma Kinetics in 2008. The Arizona-based startup has developed “solid-state” hydrogen storage, essentially transferring the gas onto a proprietary film wound in many layers inside a canister. He says the tech could challenge batteries in both efficiency and environmental friendliness.
When unspooled and run past a laser—the film moves from one reel to another, like movie film through a projector—the solid-state storage medium releases 99.99 percent pure hydrogen, which could power electrical grids, hydrogen fuel cells, cars, or hydrogen-injected diesel trucks. Plasma Kinetics asserts that its storage system is 30 percent lighter, 7 percent smaller, and 17 percent less expensive than a lithium-ion battery per kilowatt-hour. Those claims have reportedly attracted capital from the likes of Toyota, though Smith declined to confirm any investments.
Due to these successes, Plasma Kinetics had to put its plans (and patents) on hold for nearly a decade because the Department of Defense wanted to gain a lead in applying Smith’s methodology to missile tech and other military applications. Now, the startup’s hydrogen storage tech may have the chance to challenge the battery business and the trillions of dollars sunk into it worldwide.
Hydrogen (H2) is most often produced by natural gas steam reformation and electrolysis of water. “Green” hydrogen is produced when wind and solar power provide electricity for splitting water into hydrogen and oxygen by electrolysis. The hydrogen produced by these processes must be compressed or liquefied to achieve a small enough size for practical storage.
Hydrogen gas is commonly compressed to more than 2,000 psi, and in the case of fuel-cell cars like the Toyota Mirai, to as much as 10,000 psi. Multiple stages of compression and cooling are required to achieve these high pressures. Plasma Kinetics claims its process provides the same storage density as 5,000 psi compressed hydrogen gas but without compression—eliminating pumps, compressors, and chillers.
The company uses a light-sensitive, film-like “nano-photonic” material to absorb hydrogen, wound in thousands of layers inside a large canister. Each extremely thin layer has a lattice structure that binds hydrogen and prevents other elements from interfering with its absorption. The company’s process begins by connecting a hydrogen production “buffer tank” (into which electrolyzed or steam-reformed gas initially goes) to a hood with input and output pipes sitting atop a 20-foot container, which holds 70 canisters of its nano-photonic film.
On command, H2 is released from the buffer tank through the hood into the main container holding the 70 canisters. When a canister recognizes the presence of hydrogen gas, a valve inside opens, allowing gas to flow inside. The negatively charged nano-photonic film has a strong affinity for positively charged H2, absorbing it in minutes at simple atmospheric pressure.
“If you can provide 10 kilotons of hydrogen per hour to a Plasma Kinetics system, it can absorb all 10 kilotons,” Smith says. “It’s just a matter of how much you want to scale.”
Regardless of the source, the result is H2 stored in a solid state, according to Smith. The company anticipates 28 kg of H2 per cubic meter in 2023 without the need for pressure or energy to store the hydrogen. That could be useful in challenging batteries, a relatively dirty technology: Plasma Kinetics claims that its storage film and housings require no rare-earth elements.
By the end of 2023, it will have a prototype demonstration facility completed. Among those eager to see it will be Steve Christensen, a research scientist at the National Renewable Energy Laboratory in Golden, Colorado, who has extensively studied hydrogen storage and cautions that there are hurdles to its adoption.
Utilities and their investors, Christensen says, lack understanding of H2 storage and are comfortable with current utility-scale battery energy storage systems. And because they’re unsure about the potential cost savings that H2 offers through bypassing the need to compress, cool, and/or liquefy hydrogen, utilities are reluctant to pass the cost of investing in new energy storage to customers.
“Is that actually as important a driver in the cost of the technology as we might expect? It’s hard to guess now if it will be cheaper” than existing systems, Christensen says.
Smith says his movie projector–like system is nonetheless competitive and will get better as fuel-cell tech improves. He estimates that the price of hydrogen when using the Plasma Kinetics system will be less than $3.00 per gallon-equivalent, while hydrogen is currently sold in California for $16.51 per gallon-equivalent as of March 2022.
Plasma Kinetics still faces skepticism, and likely opposition, from entrenched battery interests. Smith acknowledges the long slog, and that much remains to be proven. But by force and by circumstance, he’s slowly dismantling the stack of challenges of hydrogen energy storage.
“I just took it to the next step in the same manner we do in microchip manufacturing,” Smith says.“You design [H2 storage] in layers, and each layer affects what it needs to affect.”