Abstract <p>Fuel economy in boilers is an urgent concern. Coal combustion with fuel oil is currently employed for that purpose, but this approach impairs electricity generation and releases oxides of sulfur and nitrogen into the environment. An alternative is oil-free combustion with plasma activation of the coal. Preliminary plasma activation results in more efficient combustion in the absence of fuel oil. The effectiveness of this technology is confirmed by familiar methods: engineering analysis, economic assessment, elaboration of a theory, experimental testing, and formulation of recommendations for optimizing the technology. The influence of plasma activation on the coal combustion is studied. The resulting technology for thermal preparation and combustion of coal in a cyclone furnace is an alternative to combustion with fuel oil in industrial boilers. The design of the system for regulating combustion with partial gasification of the working fuel is improved. Using this technology, it proves possible to use low-grade coal as the fuel. The emission of nitrogen oxides is decreased, and boiler performance is improved. Oil-free fuel combustion in a cyclone furnace is promising for use in power generation. It is shown that coal combustion with chemical activation or high-temperature plasma activation may be used in modernizing or constructing thermal power stations.</p>