With oil markets in turmoil amidst the global economic shutdown, competing green fuel sources are getting extra attention. One such promising alternative energy is hydrogen (H2) power. Hydrogen fuel cells – the growing commercial application of hydrogen energy – are a battery-like technology that use H2 as an input to create electricity, leaving heat and water as the only waste. Recently, Texas’ Rice University unveiled a potential breakthrough in hydrogen fuel generation – the “artificial leaf.”
As I’ve discussed before, traditional hydrogen fuel cells can be thought of as batteries that never run flat as long as the H2 keeps coming. Pressurized hydrogen is the ‘fuel’ in the tank, which then interacts with Oxygen (O2) in the air to create electricity through a chemical reaction. Fuel cells are inherently more efficient than internal combustion engines (ICE), which must first convert chemical potential energy into heat, and then mechanical work. Fuel cells are also cleaner than ICEs: the only byproduct is H2O – water—and its clean enough to drink. But that’s once the hydrogen is harvested.
The majority of hydrogen is generated through fossil fuel processes like the steam reforming of natural gas and coal gasification. Emission free hydrogen can also be produced through biofuels and green water electrolysis – where (clean) electricity is used to split water into hydrogen and oxygen.
The artificial leaf concept proven by Rice researchers is an evolution of the hydrogen generation process, able to produce H2 fuel from sunlight and water. If done right, it has the potential to be far more economical than previous iterations of hydrogen fuel cell technology. As described by Jun Lou, the lead author of the Rice University study:
“[the design] integrates catalytic electrodes and perovskite solar cells that, when triggered by sunlight, produce electricity. The current flows to the catalysts that turn water into hydrogen and oxygen, with a sunlight-to-hydrogen efficiency as high as 6.7%.”
Scientists have been working on similar solar models for some time, but until now hydrogen generation capacity was too low and the device components were far too expensive for general adoption. Not so with the new Rice design. Not only has capacity been increased, but cost-prohibitive rare earths and components have been replaced with cheaper alternatives. The solar cells in the design no longer require precious metals like platinum and have been replaced with cheaper and more abundant carbon materials.
Another advantage of this technology is that it can be used anywhere, so long as there is sufficient sunlight and water. As Jun Lou again, states:
“With a clever system design, you can potentially make a self-sustaining loop. Even when there’s no sunlight, you can use stored energy in the form of chemical fuel. You can put the hydrogen and oxygen products in separate tanks and incorporate another module like a fuel cell to turn those fuels back into electricity.”
Of course, this type of frontier tech is still in the experimental phase, years away from achieving scale or even commercial viability. Widespread adoption of this kind of technology would require massive build-outs of infrastructure – like hydrogen pipeline systems – as well as the extensive adoption of downstream products that require hydrogen fuel, like hydrogen fuel cell vehicles. Demand for H2 in chemical refining alone simply isn’t enough.
Hydrogen fuel cell vehicles (HFCVs) are already in operation around the world, with over 60,000 on Germany’s roads. China is aiming for more than 1 million HFCVs in service by 2030. That compares with just 1,500 or so now, most of which are buses. Japan, a market of more than 5 million vehicles annually, wants to have 800,000 HFCVs sold by that time, up from 3,400 currently. But demand is not yet enough to justify the billions upon billion of dollars needs for adequate hydrogen fueling infrastructure .
These targets are ambitious, but given the increasing concerns about CO2 pollution and the precarious future of the oil-based economy, investments in hydrogen technology would be worth the effort. Research, development, and implementation of this power source would facilitate transition to clean energy, reduce emissions, create jobs, and spur further innovation. This potentially closed-loop system of energy generation is entirely green, with no harmful byproducts. In its liquid form hydrogen can be transported great distances by either pipelines or more traditional land and sea transportation networks re-purposed for hydrogen shipment.
Of course, excitement over progress in hydrogen and other renewable energy adoption should be tempered with a great deal of planning, policy making, and investment. This will ensure that new technology is developed and integrated properly. That said, these difficult times have created an unprecedented opportunity to chart a new direction for the energy industry.
With Assistance from Regan Abner