Since the beginning of the industry, Malaysian palm oil mills have been utilising part of the palm biomass as an energy source for mill operation. The main constituent of the biomass used for power generation in the mill comprised part of the mesocarp fibre and most of the dry palm kernel shell called the fuel mix, at a ratio of about 60% to 40%. The entire empty fruit bunches, the remaining mesocarp fibre and most of the palm kernel shell – mainly the wet palm kernel shell were disposed of or incinerated. The objectives of this study are to compare the CO2 emission during biomass fuel combustion with diesoline combustion. The equivalent mass of diesoline was estimated using its calorific values as a basis for computing the enthalpy content of the respective fuels. Analytical results confirmed that the greenhouse gases emission (GHG) from the combustion of the ‘biomass mixture’ in a boiler is about 2.7 times that of the GHG emission from diesel combustion, when producing the same amount of electrical energy. Although green energy has its merits in helping us to preserve the fossil fuels for the use of future generations its use for power generation as a substitute for fossil comes with a price, viz: the additional GHG released to the atmosphere compared to fossil fuels. The mills use about 15% of the total fibre and 22% of the total shell produced to generate sufficient energy for processing fresh fruit bunches. The fast depleting fossil fuel reserves of the world and the environmentalist’s concern for clean energy has now brought the global attention to the surplus biomass in the mill. This has also encouraged the government to implement suitable policies to promote renewable energy generation in Malaysia.