By Jason Deign
US-listed technology firm HyperSolar is looking to develop a commercial-scale solar-powered hydrogen generation system after unveiling a working prototype last month.
The Santa Barbara, California-based company is hoping to give the hydrogen fuel cell industry a boost by removing one of hydrogen’s biggest problems: having to transport the gas over long distances.
Hydrogen “is expensive enough in the manufacturing process,” said Tim Young, president and CEO. “When you add on trucking it 500 miles in a pressurised truck, it stops making economical sense.”
Being able to manufacture hydrogen on site, using water and sunlight, could eliminate these costs and open up a vast array of potential energy applications, Young told Energy Storage Report.
These include “thousands and thousands of backup power plants” that “would all love to be hydrogen powered” because the fuel can be stored indefinitely until needed, he said.
Emitting water from hydrogen
Also, Young said, “you’ve got all this power equipment inside warehouses” that currently creates greenhouse emissions but “would love to be emitting water from hydrogen.”
HyperSolar’s plan is to put solar-powered hydrogen generation plants on top of warehouses and similar sites, next to fuel cells provided by manufacturers such as Plug Power. Admittedly that vision is still some way off, however.
A video of HyperSolar’s prototype shows the company’s patent-pending technology splitting water into hydrogen and oxygen in the lab, but not at a scale, efficiency or cost that is commercially viable.
The design contains a proprietary hydrogen production unit that consists of a high-voltage solar cell encapsulated in a protective catalyst coating, integrated into a membrane separator.
“The protective coating has been demonstrated to allow hydrogen production to run for hundreds of hours in very corrosive water, without damage,” said HyperSolar in a press release.
Demonstrating fuel cell capabilities
“To fully demonstrate fuel cell capabilities, the produced hydrogen is connected to a fuel cell that converts hydrogen into usable electricity, ultimately facilitating electrical power to illuminate the two light bulbs.”
However, Young explained: “What we used in that video were expensive gallium arsenide solar cells where were really good but would never be cost effective.”
HyperSolar is currently investigating whether it can use US-made triple-junction crystalline-silicon solar cells instead. “They would be much more cost efficient,” said Young.
The company is also hoping to double the efficiency of the hydrogen generation process, so that 10% of the energy from incoming sunlight gets captured rather than 5% at present.
Finally, a commercial-scale hydrogen generator would need to effectively capture and store the gas in volume. Young viewed this as a minor engineering problem that could be solved with pumps.
A fairly simple process
“If the solar cells are able to effectively split the water molecules, we think the piping is a fairly simple process that could be quickly perfected,” he said.
Despite the hurdles, it is also true that HyperSolar has gone a long way towards perfecting the technology for solar-powered hydrogen generation.
The company has filed patents for the means to split water molecules, separate oxygen from hydrogen, and capture the gas without losing most of it.
Plus the technology has been found to have some unlikely side effects, such as helping to purify the water used for hydrogen production.
The higher the salinity and the greater the organic content of the water, “the easier it is” to generate hydrogen, Young said. “The organics in the water are just more conducive to the process. It becomes more efficient.”
Tweaking the production process
Water salinity and organic content have forced HyperSolar to tweak its production process to include an anti-corrosive polymer coating for the solar cells and to add a commercial anti-foaming agent to the feedstock.
With most of these refinements now in train, the pieces for solar-powered hydrogen generation are “starting to come together,” Young commented.
How long it will take to get to full commercialisation is still highly uncertain, of course.
But Young, who is planning to lease a Toyota Mirai in the coming months, remains convinced there is a massive potential market for hydrogen not just in commercial and industrial settings but also in the automotive market.
“The other day I test drove a Tesla,” he mused. “It takes 25 to 30 minutes to get a full charge and there was a line eight-deep of Teslas wanting to charge.
“Two miles from there, there’s a hydrogen filling station where in four minutes you can fill your car. Elon Musk says hydrogen is and always will be the technology of the future. I’m trying to prove him wrong.”