A coal or carbonaceous material upgrading process for power station use, the process comprising a number of steps. First comminuting the coal or carbonaceous to a comminuted material. Second pre-treating the comminuted coal with a pulsing single frequency microwave and vacuum to reduce its water and oxygen content; the pre-treating stage being carried out at a temperature of up to 180 C. Third, treating the pre-treated comminuted material with a pulsing single frequency microwave energy under vacuum to optimize the volatile organic materials; the treatment stage being carried out at a temperature of up to 350 C. Next pyrolyzing the treated coal with a pulsing single frequency microwave and vacuum to produce a hot gas and a solid carbon residue; the pyrolyzing stage is carried out at a temperature of up to 720 C. The solid carbon residue can then be separated from the hot gas, the volatile organic materials condensed to produce a liquid hydrocarbon product and a gas product; and the solid material and the gas product fed to a power station to produce electricity therefrom. The microwave energy applied at each of the stages has a single frequency of 100 megahertz to 300 gigahertz, has circular polarisation, and is pulsed at a frequency of 2 to 50 kilohertz. The pre-treatment step, the treatment step, and the pyrolysis step can be done under vacuum.