Presently, coal is ground to a powder then sprayed into a furnace for more even and complete combustion that heats water to steam and steam to super heated steam. The expansion of steam to super heated steam operates the turbine generating electricity.
The super heated steam then must be cooled to steam by evaporating water. This requires volumes of water evaporating into the atmosphere. Then the cycle is repeated to super heat the steam to forcefully expand and operate the turbine.
The coal emissions of carbon dioxide, sulfur dioxide, nitric oxide, hydrochloric acid, and hydroflouric acid are related to the volume and type of coal burned. One pound of coal produces approximately the same BTU of one gram of hydrogen without the Coal emissions.
Hydrogen can be made by spraying super heated steam over finely ground iron rust. This will yield hydrogen, cooled steam, and red paint pigment without sending large volumes of surface water into the atmosphere. The hydrogen produced is sprayed into the furnace as a second fuel with the powdered coal dust decreasing the amount of coal required to produce the BTU to super heat the steam. (The ratio of coal dust to hydrogen is not known by this writer.) With hydrogen as an additional fuel in the furnace, the cooled steam is then reheated to super heated steam driving the turbine to produce electricity. The amount of coal burned to produce the electricity is decreased. The amount of coal emissions is reduced. The amount of the coal or natural gas fuel cost is decreased. I do not see any reason the same hydrogen boost cannot be used in natural gas fired electrical generators.
Essentially, hydrogen is a byproduct of cooling super heated steam by a method other than evaporating water. The natural gas required to fire all of the existing coal fired electric generators would consume most of not all of US natural gas production. Therefore use hydrogen to make the coal and natural gas electric generators more efficient.