The objective of the experiment was to evaluate the energy efficiency of the phytoremediation process, supported using energy crops. The scope of conducted work includes the preparation of a field experiment. During the evaluation, 2 factors were into consideration – total energy demand and total energy benefit. The case study, used as an origin of data, consists a 3-years field study, conducted with the use of 2 energy crops – Phalaris arundinacea L. and Brassica napus L. The area subjected to the experiment was polluted with polycyclic aromatic hydrocarbons (PAHs) and herbicides, classified as phenoxy acids (2, 4 D). The experimental design consisted of 4 groups of fields, divided according to the used plant species and type of treatment. For each energy crop, 2 types of fertilization strategies were used. Therefore the 1st and 3rd sets of fields were not treated with any soil amendment while the 2nd and 4th sets were fertilized with compost. The obtained data allowed to observe that the cultivation of P. arundinacea L. and B. napus L. allowed a positive energy balance of the process to be achieved. However, it should be noted, that the B. napus L. growth in the first vegetation season was not sufficient to fully compensate a total energy demand. Such a goal, in the mentioned case, was possible after the 2nd vegetation season. The collected results show also that the best energetic potential combined with the most effective soil remediation were obtained on the fields with the cultivation of P. arundinacea L. fertilized with compost. The number of biofuels, collected from the 1 ha of such fields, can reach a value equal even to12.76 Mg of coal equivalent.