With their high energy densities, fuels are important for various applications, especially in thermal power plants that primarily rely on fossil fuels such as coal, oil, and natural gas. Despite economic advantages, fossil fuels raise environmental and climate concerns. Amid this situation, biomass emerges as a valuable alternative for energy purposes due to its carbon and hydrogen content, though its performance is affected by challenges such as low density, energy density, and high moisture content. Key parameters influencing biomass energy conversion include density, particle size, moisture content, and chemical composition. Hydrogen, with a high specific energy, also offers a promising low-emission alternative to conventional fuels but requires pressurization or liquefaction for practical use. Ammonia, with higher volumetric energy density, presents a more efficient hydrogen storage and transportation option but demands substantial energy to release hydrogen. In addition, integrating hydrogen and ammonia in power generation offers several decarbonization scenarios, including ammonia co-firing with coal, ammonia combustion/co-combustion to replace natural gas, and hydrogen-ammonia co-combustion. These strategies highlight the potential of alternative fuels for low-carbon power generation.