Hydrogen safety, the Hindenburg, and Rockford
By Jeffrey Havens
It burst into brilliant flame at about 7 p.m., on May 6, 1937, in Lakehurst, N.Y. The German-made zeppelin, Hindenburg, caught fire, fell to the ground, and killed 35 people. To this day, the Hindenburg disaster is synonymous with the perceived dangers of the use of hydrogen, even among very knowledgeable and educated people. But is this reputation deserved? After thoroughly researching the issue, I believe it is not. The Hindenburg disaster is more a testimony of the dangers of petroleum products rather than hydrogen.
In 1997, a retired NASA scientist, Addison Bain, reported at the National Hydrogen Associations annual U.S. Hydrogen Meeting that the most probable cause of the Hindenburg disaster was the combination of natural and engineered factors. The presentation was also the subject of the cover story in the May 1997 issue of the Smithsonian Institutions Air and Space Magazine. The factors he reported converged to yield a spectacular petroleum fireball, similar to the ones that engulfed the World Trade Center towers on September 11th. The fabric that constituted the outer shell of the Hindenburg was made of cellulose and coated with a derivative of petroleum that was ignited by static electricity discharges from passing clouds. The hydrogen in the Hindenburg was not used as fuel but as a lifting gas. Therefore, it was not as carefully contained as it would have been, had it been used as a fuel. There is no doubt that hydrogen contributed to the fire, but most of the fire that was documented by the famous footage, was that of the cellulose and petrol. The moral of the story is to not coat your dirigible with petrol chemicals.
In his book, Tomorrows Energy: Hydrogen, Fuel Cells, and the Prospects for a Cleaner Planet, Peter Hoffmann, summarizes the latest in hydrogen safety issues, that basically states that hydrogen poses no more risks of disaster than fossil fuels such as gasoline. In fact, there are several safety advantages of using hydrogen over fossil fuels. How is this possible? The answer lies in the physical and chemical properties of hydrogen. It is because of hydrogens extreme reactivity with oxygen that makes it such an ideal fuel. Hydrogen burns quickly, so there is no continual burning and subsequent emission of heat and smoke after ignition as there is with petrol. In addition, there is no global warming carbon dioxide given off as a product of the reaction, but only water and energy in the form of light, sound and heat photons. This means that should disaster occur, people would have a better chance to live if they survived the initial explosion. Had hydrogen been used to fuel the jets that were crashed into the World Trade Center buildings, those structures would still be standing and scores more would not have been killed or injured in the ensuing petroleum fireball, due to hydrogens unique properties.
Perhaps the biggest fear people have concerning hydrogen is what makes it such a great fuel: its extreme reactivity. However, hydrogen is very difficult to ignite in a ventilated room and nearly impossible outdoors. Specifically, in a closed space, hydrogen can be exploded in concentrations ranging from 18 to 59 percent by volume, in air, whereas gasoline and jet fuel can be exploded in concentrations from 1.1 to 3.3 percent. However, it takes about 1,000 times less energy (20 micro-Joules) to ignite hydrogen, compared with gasoline (240 mega-Joules), but a 1976 Stanford Research Institute study states, in the open, without confinement, it is almost impossible to bring hydrogen to an explosion with a spark, heat, or flame. But what about the confinements of a car or room? How can we detect hydrogen should a leak be present?
Hydrogen, like natural gas or methane, and carbon monoxide, is colorless and odorless. Natural gas that you have in your house is detectable by smell because another gas, a type of mercaptan, is added to it. We also have carbon monoxide gas detectors in our home. Similarly, scientists at the National Renewable Energy Laboratory have designed a hydrogen detector made of optical fibers, tungsten and palladium metals, and a light detector. The metals change color, which the light detector reads, to warn of dangerous concentrations of hydrogen in rooms and vehicles. There are hopes that an additive similar to mercaptan can be incorporated into hydrogen.
Another issue that people often bring up is how can hydrogen be safely contained in a car or truck? In Kenneth S. Deffeyes book, Hubberts Peak: The Impending World Oil Shortage, he states that there are already gas tanks that contain natural gas that have successfully demonstrated their ability to withstand collisions. He indicates that the vehicle crumples around the tank because of its fortitude. The same type of tank strength has been built for hydrogen vehicles. However, should a puncture of the specially made tank occur, BMW tests show that hydrogen escapes without explosion. Further tests reveal that the lower the safety standards for the tanks, the greater the risk of explosion. Safe containment of hydrogen in homes and buildings has similar but less severe risks than that of moving vehicles. In homes and buildings, existing natural gas lines could be modified by using special pipes inserted into existing lines to deliver hydrogen. This has already been successfully done in the Ruhr region of Germany. Hoffman writes, …in more than 50 years of operation, there has been no major accident from escaping hydrogen or potentially explosive hydrogen-air mixtures…
Although the fears of hydrogen are greater than that of petrol, the risks are not. They are just different. The fears are similar to the ones that were faced 100 years ago when we began our mass use of gasoline. They are fears of the unknown. Regardless of the safety issues, hydrogen will be our future energy delivery and storage system. Rockford would do well to begin to lead in this area of wind, solar, hydrodynamic, geothermal, biomass, and fuel cells energy systems. Several businesses in this area already have parent companies that are leading the way in alternative energy, but not at the local level. I urge the local political and economic leaders, as well as the citizens to forge a new future for Rockford based on the research, development manufacturing, and sales of alternative energies. The jobs would be good-paying and secure rather than the low wage, no security, service-oriented jobs we have been cranking out the last 20 years.