Friday, February 28, 2014

‘New’ Fuel has Security Implications

There is an interesting post over at about a potential replacement for hydrocarbon fuels, anhydrous ammonia. The author, Kurt Cobb describes six advantages to the use of ammonia:

• It contains no carbon, therefore no greenhouse gasses produced;
• Well-known processes for making ammonia;
• Worldwide ammonia production industry;
• Distribution technology understood;
• Enviable safety record (more on that later);
• Creates nothing that can be classed as pollution

In general this is a well thought out and well documented discussion about the pro-ammonia arguments. I do however, take exception to the glib statement about the anhydrous ammonia safety record and note that there are some serious security issues that must be taken into account in this discussion.

Safety Record

Anhydrous ammonia is a toxic inhalation (TIH) hazard chemical. This means that relatively low concentrations in the air can kill people. Kurt does make one good point about this particular TIH chemical; it is detectable and obnoxious at concentrations much lower than the lethal concentration in the air. This does mean that most people on the periphery of an ammonia cloud will be self-alerted to the danger so that they can undertake evacuation efforts.

One of the reasons that there have been fewer deaths from large scale accidents with anhydrous ammonia as compared to chlorine gas (another industrial scale TIH chemical) is that anhydrous ammonia is lighter than air so it generally rises above ground level in a release. Chlorine gas is about twice as heavy as air so that it hugs the ground.

You have to be careful about that word ‘generally’ there are all sorts of thing that can happen that will affect the rate of ascent of the gas cloud including air temperature profiles, amount of humidity in the air and the wind speed in the area. And, of course, if the gas cloud is inside of a building, all bets are off. And even if the bulk of the release cloud rises above ground level, air mixing is sure to keep non-lethal ammonia concentrations over a wide swath of down-wind ground, making life miserable for people in the short term.

As the 2009 incident in Swansea, SC showed even a gas cloud that is generally rising can cause deaths and this was from a relatively small volume release. If there is a drastic increase in the amount of anhydrous ammonia used in commerce the number of accidents can be expected to increase and I suspect that the accident rate would increase as small spills tend to cause personnel to evacuate the area rather than take immediate actions to stop the leak.


Anhydrous ammonia is a DHS chemical of interest (COI) for the CFATS program. Any facility that has over 10,000 lbs of anhydrous ammonia on site (about 1800 gallons, a relatively small pressure tank) is required to register with DHS and to submit a Top Screen. The current extended CFATS community includes more than 40,000 facilities that have submitted Top Screens. That number would significantly increase if we replaced oil/gas fired energy producing facilities with anhydrous ammonia fueled facilities.

Once a Top Screen is submitted DHS looks at the potential effects of a release of chemicals like anhydrous ammonia to determine if they are at high-risk for terrorist attack. While DHS will not share the details of their assessment regime for security reasons, it is clear that the more people that would be affected by a release the higher the probability that DHS would declare the facility to be at high-risk. That declaration brings with it the requirement to fully implement the security standards set forth in the CFATS regulations.

Those security measures would seriously add to the cost (capital and operational) of an anhydrous ammonia fueled power generation facility. Coal, oil or natural gas power plants are not currently covered because of fuels (they may be covered for other chemicals) since coal, oil, and natural gas are not listed COI.

TSA Security

Anhydrous ammonia is specifically listed {§1580.100(b)(2)} in the TSA freight rail security regulations (49 CFR §1580.100 et seq) as a rail security-sensitive material. These materials require special handling by shippers, railroads, and receivers in high-threat urban areas (HTUA).

These special handling requirements, including train speed limits, will also add costs to the use of anhydrous ammonia as a power generation fuel. Again, these costs need to be taken into account in determining the economic viability of this ‘new’ fuel.

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