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 point here is that there is an extremely wide range of possible costs for Hydrogen gas! Proponents of Hydrogen always cite the $3 to $5 per CCF, which means $6 to $10 per pound (200 cf) of compressed Hydrogen gas, or $12 to $20 for enough Hydrogen gas to contain the equal energy as one gallon of gasoline.