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.
1 A Weil McLain gas boiler that produces 77,000 BTU and uses natural gas can cost $1,200 to $1,500. 2  A gas boiler that produces a higher energy output can also be purchased. 3  For example, a Burnham gas boiler that provides 118,000 BTU and uses natural gas can cost $1,900 to $2,700. A gas boiler that produces a higher energy output can also be purchased. 2  For example, a Burnham gas boiler that provides 118,000 BTU and uses natural gas can cost $1,900 to $2,700.