The novel goal of the present research is to integrate response surface and life cycle assessment methods to reduce the environmental impacts of mechanical power generation in a diesel engine fueled by diesel-biodiesel blends. Environmental impacts of mechanical power generation in an OM 314 diesel engine under the effect of biodiesel were investigated using the life cycle assessment method. Response surface methodology was used to find the optimum percentage of alga biodiesel in diesel-biodiesel fuel blends under the effects of different engine loads and speeds. In the optimization process, the dependent variables were engine performance characteristics and emissions. A blend containing 57 % diesel and 43 % biodiesel was found as the optimum fuel blend. The environmental impacts of the optimum diesel-biodiesel blend were calculated by the CML-IA baseline impact assessment model and compared with those of pure diesel and pure biodiesel. The results showed that the values of abiotic, abiotic fossil fuel, and ozone layer depletion indicators decreased by 16.09–44.09 % compared to pure diesel. Also, the values of other indicators decreased by 16.74–131.84 % compared to pure biodiesel. Normalization process showed that the marine aquatic ecotoxicity was the main indicator for all studied fuels.
