Agricultural waste products have huge energy content and have the potential to be harnessed to generate energy. This paper presents experimental investigation results on the biomass obtained from Malaysia's agricultural sector mixed with coal for combustion to generate power. A total of seven different types of biomass samples have been considered, mainly oil palm trunk, oil palm fruit shell, oil palm fruit fiber, oil palm empty fruit bunch, oil palm leaf, oil palm frond, and chicken manure. They were mixed with semi-bituminous coal at several mixing percentages (2 biomass, 5 biomass, 10 biomass, 15 biomass). The mixtures then underwent analyses in the form of energy content or calorific value test, ultimate analysis, and proximate analysis. The results have been presented in terms of the energy content, carbon content, degradation temperature, and combustion-produced matters. Results show that the energy content of the coal-biomass mixture is generally lower than that of pure coal. Biomass can be co-fired with coal but at a low percentage, estimated to be not more than 10 biomass content. A biomass type that has potential and should be studied is the oil palm fruit shell. However, a balance is required for any electricity generation application between the energy content per unit weight and the other parameters such as properties of the released flue gas and ash properties © 2021 WIT Press, www.witpress.com.