Since it has greater thermal conductivity than air and can provide more efficient cooling ability, gaseous hydrogen traditionally serves as a heat transfer medium for cooling electrical generating equipment. Gaseous H₂ is circulated through heat exchangers in the shell of the generator to cool the rotor. Rotors at hydroelectric plants only run at 10% of the speed that a typical steam rotor completes and do not therefore require H₂ for cooling.

In the primary piping system, hydrogen is added to cooling water in the boiling water reactor to suppress Intergranular Stress Corrosion Cracking (IGSCC). During the early 1980s, only a small number of power plants had caught on to the benefits of hydrogen, but after successful demonstration of crack suppression, more utilities have since adopted the technique. Hydrogen injection is superior to other methods of controlling IGSCC because it can be used in areas that are not physically accessible to treatment by other means, such as induction heating. An additional use for hydrogen also lies in the prevention of radiation-assisted cracking in the reactor core.