Imagine a zero-emission fuel that can be squeezed out of polluted water using a process powered by renewable energy. We may be closer to this reality than you think.
If you’re new to the water-splitting topic this may sound a bit gimmicky, but it’s for real. Similar technologies are under development by researchers around the globe. MIT and Lawrence Berkeley National Laboratory provide two among many examples in the U.S. And the U.S. Navy is testing a fuel-producing device based on seawater.
Hydrogen and renewable energy
Hydrogen is not a particularly energy-dense fuel, but it is abundant. And energy planners have long eyeballed it as a key resource for the global economy of the future.
However, referring to hydrogen as a “zero-emission” fuel under present circumstances is somewhat disingenuous. There are no tailpipe emissions when hydrogen is used in a fuel cell vehicle, for example, but the main source of hydrogen was (and still is) natural gas.
Using an electrical current to split water is another way to get hydrogen. But that process is not viable in a fossil fuel economy, at least not on a large scale. It requires a tremendous amount of electricity.
In the U.S., coal and natural gas still dominate the electricity production landscape, so that’s a no-go in terms of climate impacts. The local impacts of fossil fuel extraction also make a case against sourcing hydrogen from natural gas on a large scale.
Now that the age of renewable energy is gathering steam, the hydrogen-sourcing picture looks much brighter.
Wind and solar now provide a pathway for powering the water-splitting process on a large scale without relying on the fossil fuel chain. In addition, the intermittent nature of wind and solar power has motivated the search for large-scale energy storage solutions, and hydrogen fits the bill.
In Europe, for example, policymakers are looking at wind-powered, water-splitting systems that use the existing natural gas distribution network to store and transport hydrogen.
HyperSolar and the hydrogen economy twofer
Conventional water-splitting requires clean water, and that dials up some important water resource issues. Pre-treating water also add complexity to water-splitting systems, bumping up costs.
HyperSolar is a good example of a next-generation solution. The HyperSolar system was engineered specifically to be deployed in untreated water. The result is a twofer: a zero-emission fuel and cleaner water.
That’s an important advantage in the future energy market. In the electric vehicle sector, for example, batteries have already established a strong foothold. The water treatment aspect of next-generation hydrogen production could provide an added value that helps fuel cell electric vehicles to carve out a niche.
How does it work?
Water splitting can be accomplished in different ways depending on the source of the electricity.
In a solar-based system like HyperSolar’s, the water splitting system consists of a solar cell submerged directly in water. When exposed to sunlight, the charge generated by the solar cell results in a flurry of bubbles that are visible to the naked eye.
Here’s a general description of from the National Renewable Energy Laboratory:
“The cleanest way to produce hydrogen is by using sunlight to directly split water into hydrogen and oxygen. Multijunction cell technology developed by the photovoltaic industry is being used for photoelectrochemical (PEC) light harvesting systems that generate sufficient voltage to split water and are stable in a water/electrolyte environment.”
The HyperSolar system includes a protective coating for the catalyst, enabling the system to operate in corrosive water. The lifespan for the catalyst in the prototype is “hundreds of hours,” the company says.
A high-voltage solar cell that mimics photosynthesis is a second critical element in the system.
Earlier this year, TriplePundit profiled HyperSolar and described these two aspects of the technology in detail, arriving at this conclusion:
“The combination of these two elements provide a distinctive economic advantage. But is it enough to relaunch the hydrogen economy? Only time will tell.”
It looks like some companies are not letting any grass grow under their feet. The leading rail transportation company Alstom, for example, just unveiled a hydrogen fuel cell version of its popular diesel-powered engine. The new model is aimed at urban rail systems that are not likely to become electrified in the near future.
The U.S. lags behind Europe and Japan in the hydrogen economy, but it looks like that is about to change. Earlier this year the Energy Department described a “deep decarbonization” concept for the U.S. economy, and last month it issued a request for public input:
The U.S. Department of Energy (DOE) has issued a request for information (RFI) to gather feedback on H2 @ Scale, which is a concept to enable wide-scale deployment of hydrogen to deeply decarbonize the U.S. electricity generation, transportation, and industrial sectors.
For now, the concept involves leveraging U.S. shale gas resources, but it appears that the Energy Department is moving swiftly beyond that. The agency is particularly interested in hydrogen production based on renewable energy.
Another potential power source for large-scale, non-fossil hydrogen production consists of reclaimed waste heat from nuclear power plants and other industrial operations.
As for the shale gas angle, the Energy Department makes it clear that continuing to produce hydrogen from shale gas would only count toward deep decarbonization if it is coupled with carbon capture.
If the cost of carbon capture is excessive, that could make renewable technologies like the HyperSolar system more competitive in the marketplace.
The next steps for HyperSolar involve scaling up, so stay tuned.
Image (screenshot): courtesy of Hypersolar via YouTube.