With the constant increase of fossil fuel prices and resources depletion, the researchers look beyond the usual alternative fuels for diesel engines. A lot of research is going on the employment of plastic polymers as fuels since they have a high potential to reduce diesel oil consumption and many of the aspects of their operation in diesel engines are not clarified yet. The major advantage of plastic polymers is the high calorific value, a widespread availability, and lower prices if they come from recycling. The paper presents the results from the research on a novel polyethylene blended diesel fuel and its use as alternative fuel for combustion in diesel generation plants. The authors investigated the formulation, injection, combustion and emissions of a new polyethylene-diesel fuel, obtained by an original process. The low density polyethylene (LDPE) has been mixed 5-40% by wt. with diesel by a new technology at 200 deg. C, (a much lower temperature than that of liquefaction or thermal cracking). The experimental equipment has been developed by the authors for the production of these novel fuels and the mixtures obtained had a high calorific value. The combustion of the new fuels has been investigated in a diesel engine and showed that polyethylene blended fuels can be burnt with efficiency but the emissions of the new alternative fuel were in general, higher at than those of the diesel oil and in need of improvement. The results show advancement in formulation of new alternative fuels produced from plastic polymers and diesel oil, for power generation plants.