This research reviews the impact on emissions from the engine fueled with the fuel containing a large share of bio-components, in particular with 30% n-Butanol. The research was carried out using a diesel engine. It has been shown that it is possible to achieve a double positive ecological effect concerning CO2 emissions. There was a decrease in CO2 emission from the engine with the fuel contained a significant share of bio-carbon. At the same time, NOx and Filter Smoke Number (FSN) emissions have been reduced together (FSN in large percentage). Usually, if NOx emissions are reduced, FSN increases, and vice versa. The paper shows also that the use of n-Butanol (bio, but nonfood) in the future is more effective than larger amounts of higher fatty acids methyl esters, although the full withdrawal of these esters seems unjustified.