Fuel Cell Nation

How Safe is Hydrogen?

Now that I have your attention, I can tell you that it's pretty safe. But explosions like the picture on the left can happen. The photo is from the 2007 article "Blast Waves and Fireballs Generated by Hydrogen Fuel Tank Rupture During Fire Exposure" (Robert Zalosh, Firexplo). (Full Disclosure: Bob Zalosh has consulted for me on hydrogen safety issues at Giner Electrochemical Systems, LLC.)

The above black-and-white photo is an infrared image of the 7.7 m-diameter fireball that was taken 45 ms after rupture of a compressed hydrogen tank. This rupture was caused by putting a 265 kW propane burner directly under a hydrogen tank that had been installed in place of the fuel tank under an SUV. All protection normally provided by a pressure/thermal relief device had been disabled, in order to study the resultant explosion. The hydrogen tank failed catastrophically 12 min 18 seconds after the propane burner was ignited. This was obviously an aggressive test, and would likely only occur to a hydrogen-fueled vehicle if a gasoline leak ignited underneath. (I have not searched for documentation of the explosion resulting from a comparable experiment with a gasoline-fueled car, but I imagine the fireball could be bigger than the above hydrogen-fueled fireball!)

Results more favorable to the use of hydrogen as an automotive fuel have been provided by Michael Swain at the University of Miami, in the 2001 U.S Department of Energy-funded paper Fuel Leak Simulation.

H2 car on Left, Gasoline on Right, t = 0

H2 car on Left, Gasoline on Right, t = 0 min 3 sec. Ignition of both fuels occur. Hydrogen flow rate 2100 scfm. Gasoline flow rate 680 cc/min.

Swain set fire to two cars, one fueled by gasoline and the other by hydrogen. The gasoline car had a 1/16" puncture in a fuel line. The hydrogen car had a leaking hydrogen connector.

H2 car on Left, Gasoline on Right, t = 1 min 0 sec. Hydrogen flow is subsiding.

H2 car on Left, Gasoline on Right, t = 1 min 30 sec. Hydrogen flow almost finished.

Gasoline-fueled car, t = 2 min 20 sec. Deflagration in the interior

The gasoline-filled car was completely engulfed in flames by 2 minutes 20 seconds, while the hydrogen car was essentially undamaged. Whereas the gasoline fire started as the result of a simple, small hole in the fuel line, for the hydrogen fire to occur, it would have taken the catastrophic failure of four separate safety systems, all at the same time, a highly unlikely occurrence.

What this blog post shows is that it is oftentimes difficult to compare the safety of alternative technologies. In some evaluations, sometimes "Technology A" is safer, while with other evaluations it turns out that "Technology B" is safer. Bottom line, hydrogen isn't so bad!

Navy R&D 100 Award

One of this year's recently-announced 2011 R&D 100 Awards is the Autonomous vehicles, fossil-fuel free. This "Cryo-Force Power-Cell System" (CFPCS) was developed by Sierra Lobo Inc., Milan, Ohio, with funding from the Department of the Navy, Office of Naval Research (ONR), Arlington, Va., and the Naval Undersea Warfare Center (NUWC), Newport, R.I. The Award states that the CFPCS is "...an integrated, closed-loop liquid oxygen and liquid hydrogen [-fueled] proton exchange membrane (PEM) fuel cell system, [and] has been designed to help unmanned underwater vehicles (UUVs) transition away from large-battery and fossil fuel technologies. ... The significant technological advancement is the integration of cryogenic pure reactants with a fuel cell system while meeting U.S. Navy specifications of storing 50 kg of oxygen and delivering 0.1 to 100 g/min of oxygen to support a 10 kW fuel cell system."

R&D Magazine describes the CFPCS as "Technology: Closed-loop fuel cell power system." Given that this is not what fuel cell people call a closed-loop system (i.e. one that makes its own fuel and oxidizer, A.K.A. a regenerative fuel cell), but merely a fuel cell system that stores it's exhaust (similar to a closed circuit rebreather SCUBA diving system), I thought I'd check for any other product details that needed clarification.

The untitled picture on the left is shown in the R&D Magazine article as if it is a photograph of the new 10 kw Sierra Lobo CFPCS installed in a UUV test bed. Having never heard that the Navy demonstrated a complete cryogenic reactants-based 10 kW PEM fuel cell system in a UUV form factor, I thought I'd look to see what Sierra Lobo has reported. Well, the picture on the right is Sierra Lobo's 1 kWe brassboard test system as it appears on their Unmanned Underwater Vehicle Power Systems page. I had to use Google to find Sierra Lobo's version of the UUV demonstration, and found their YouTube video:

 

I'm confused why Sierra Lobo has not updated their Web site to include a photograph of their UUV brassboard, or a link to their YouTube video!

Hydrogen and Professional Bicycling

During my recent TV viewing of the USA Pro Cycling Challenge, I had a good look at the jerseys of the Garmin-Cervélo team. (Full Disclosure: I own a Cervélo R3 that I love!) I noticed that one of the sponsors was Tata! Tata, in the form of Tata International's Tata Consultancy Services. I believe that this is the first time a company with a fuel cell tie-in has sponsored a professional bike team! (Tata also sponsored the Cervélo Test Team in 2010 before it was combined with Garmin's team.)

Tata's involvement in fuel cells is two-fold:

In the November 22, 2007 Times of India article Tata-ISRO team up to launch hydrogen-powered vehicle, we learn that Tata teamed with the Indian Space Research Organisation on a pilot project to see whether hydrogen can be used to fuel automobiles. Unfortunately, this project apparently got canceled, because I can't find any subsequent announcements by either Tata or ISRO of a hydrogen-powered demonstration vehicle.

October 07, 2010, in Sun Catalytix Corporation completes $9.5-million Series B funding round, Tata announced that it lead the latest round of Sun's funding. Sun Catalytix is a startup spun out from the MIT research lab of Professor Daniel Nocera, commercializing novel electrolyzer technology. In January, 2010, the U.S. Department of Energy (DOE) selected Sun Catalytix as one of only 37 recipients from over 3600 applicants for ARPA-E's first-round of funding for transformational energy technologies.

Among their conglomerate's activities, Tata also manufactures bicycles and components.

I wonder when the first company specializing in renewable energy will sponsor a pro sports team?