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Published on January 2nd, 2015 | by Tina Casey


With This Modest Little Machine, US Navy Could Rule The Seas

January 2nd, 2015 by  

Well, the US Navy already does rule the seas, but this contraption could make the Navy even rulier than it is now. It’s a device for capturing carbon dioxide from seawater, and it also generates hydrogen as a byproduct, which means that you have your two basic ingredients for making your own fuel-on-the-go. That’s good news for the Navy, and that thing about the hydrogen could also mean there’s another pathway to sustainable hydrogen for fuel cell electric vehicles.

The real beauty of the device, dubbed the Electrolytic Cation Exchange Module, is that the whole process takes place without requiring additional chemicals or creating toxic byproducts. That’s a huge advantage compared to the conventional processes for recovering CO2 from seawater.

This thing crossed our radar back in 2012 and it won a coveted Popular Science “Best of What’s New” award last fall, so let’s check in again and see what we have to look forward to in 2015.

Navy CO2 and hydrogen from seawater

Electrolytic Cation Exchange Module (cropped) courtesy of US Naval Research Laboratory.

Capturing CO2 And Hydrogen From Seawater

The Electrolytic Cation Exchange Module, or E-CEM for short, has been under development by the US Naval Research Laboratory.

That research passed a significant milestone back in 2009, when researchers modified a standard chlorine dioxide cell and an electro-deionization cell to release CO2 from seawater, and generate hydrogen as a byproduct.


That process generated feasibility studies with enough promise to justify building the electrochemical cells into an integrated “skid,” and to scale up the volume of seawater for further evaluation.

The process, as described by NRL, is similar to the familiar Fischer-Tropsch process used to convert hydrogen and carbon monoxide to liquid fuel. In that process, the raw materials are typically sourced from coal or methane, as well as biomass.

The attraction of seawater is its high concentration of CO2. Here’s what the Navy has to say about that:

CO2 is an abundant carbon resource in the air and in seawater, with the concentration in the ocean about 140 times greater than that in air. Two to three percent of the CO2 in seawater is dissolved CO2 gas in the form of carbonic acid, one percent is carbonate, and the remaining 96 to 97 percent is bound in bicarbonate.

When it caught our eye in 2012, E-CEM was still in the laboratory stage, so now let’s scoot forward to last fall’s Popular Science award for CO2 and hydrogen capture.

Many Fuels From The Sea

The E-CEM is still operating at the lab/research scale, but it has already demonstrated proof-of-concept for converting CO2 to hydrocarbons, which can be used to produce liquid natural gas, compressed natural gas, and the military grade liquid fuels F-76 and JP-5.

In addition, last year the research team demonstrated that synthetic fuel from the E-CEM could be used to power an internal combustion engine. Well, it was a pretty small engine (the engine was in a commercially available radio-controlled aircraft), but the key point is that the engine required no modification, and the aircraft actually made it into the air.

So Are You Ready For An S-EV?

S-EV would be short for seawater electric vehicle, only of course you’re not dumping buckets of seawater into your car, you’re driving a fuel cell EV (FCEV) that runs on hydrogen derived from seawater.

We’ve been having a rather interesting discussion about FCEVs compared to battery EVs, so for now let’s just say that FCEVs are way behind the curve when it comes to cracking the EV market.

However, as recently expressed by Hyundai, some auto makers have good reasons for promoting FCEVs, and California is fully committed to kickstarting the US FCEV market with a solid hydrogen fueling infrastructure, so it’s time to get real and assume that FCEVs will eventually find their place in the personal mobility landscape.

That means it’s time to get super-serious about finding sustainable sources for hydrogen, which is currently sourced primarily from natural gas (yes, that natural gas).

Sustainably sourced hydrogen from biogas and wastewater is already in the works, so we’ll be keeping a close eye on this seawater thing to see if there’s a possibility of moving from a ship based fuel-on-the-go model to a cost-effective land based facility that could supply hydrogen for ground vehicles, sourced from seawater.

For that matter, we’re already seeing solar companies pair up with auto manufacturers — SolarCity and Honda, for example — to provide property owners with the means to generate solar-sourced electricity for their BEVs. From there it’s only a hop, skip, and a jump to enabling solar-powered hydrogen production from water, so stay tuned.

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About the Author

specializes in military and corporate sustainability, advanced technology, emerging materials, biofuels, and water and wastewater issues. Tina’s articles are reposted frequently on Reuters, Scientific American, and many other sites. Views expressed are her own. Follow her on Twitter @TinaMCasey and Google+.

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