One exception to note: If the food's sitting in an environment where the temperature is over 90Â°F, the USDA says the food should only be left out for one hour, so keep an eye on the clock if you're serving food on a hot day!
Estimated cost of hydrogen per kilogram in a variety of scenarios. With all of this in mind, here are the cost estimates per kilogram (which each include $1.25 for taxes): Hydrogen from natural gas (produced via steam reforming at fueling station). $4 â $5 per kilogram of hydrogen.
The natural gas use in a an ammonia plant using the steam reforming process ranges between 28 and 35.5 GJ/tonne, of which about 20-22 GJ/tonne of ammonia is used as feedstock, 7.2-9.0 GJ/tonne is fuel consumed in the primary reformer, and the remaining 0.5-4.2 GJ/tonne is used in auxiliary boilers and others.