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.
Also, the calculation uses only one boiler efficiency.Steam is being generated at 100 psig and is being returned to a deaerator tank operating at 10 psig. Fuel cost is $9.50/MMBtu, and boiler efficiency is 80%. $11.67 per 1,000 lbs.