TECHNOLOGY FOCUS - POLYMERS - Preferred Method: Before the extraction step, the method comprises (a1) feeding methanol and oils and/or fatty acids continuously in the extraction step with a mass ratio between the flow-rate of methanol and flow-rate of fatty acids and/or oils of 1.2-2; and after the extraction step, esterifying with methanol the mixture of methanol and fatty acids in output from the extraction step, obtaining a mixture of fatty acids methyl esters and methanol. The esterification step occurs simultaneously with another step (b1) of removing percentages of gaseous methanol from the esterification step, and anhydrifying and then returning the anhydrified fractions into the esterification step, to maintain the percentage of water produced in the esterification step at a level of less than 0.15 mass%. The method comprises after the esterification step, (c) an additional step of combining the fraction of deacidified triglycerides obtained in output from the extraction step with the mixture of methanol and fatty acids methyl esters in output from esterification step; separating the methanol from the mixture in output from step (c), thus obtaining a neutral mixture of methyl esters and triglycerides; and (d1) feeding the neutral mixture of methyl esters and triglycerides to diesel engine(s), optionally coupled to current generator(s). It comprises after step (c), transesterification with methanol of the mixture in output from step (c), obtaining a transesterified mixture of glycerin, methanol, and methyl esters; and after the extraction step, transesterification with methanol of the fraction of deacidified triglycerides in output from the extraction step. After the transesterification step, the transesterified mixture is neutralized (e1), and methanol from the transesterified mixture is separated (step e2). After (step e2), the mixture in output from (step e2) is separated into its components of glycerin and methyl ester (e3). All steps from (a1) to (e3) are performed continuously. Preferred Parameter: The fresh or recycled oils and/or fats have free fatty acids (FFA) acidity value of greater than or equal to 1%. The extraction step occurs in pulsed packed column(s), at 35-60degreesC and at atmospheric pressure, where column packing is a structured packing. The esterification step occurs in the presence of an acid catalyst at 60-110degreesC, at the corresponding pressure due to the vapor pressure of methanol and to the load losses of the system at the reaction temperature. The extraction step lowers the free organic acidity contained in the fresh or recycled fats and/or oils down to FFA value of less than or equal to 0.5%. EXAMPLE - Crude palm oil (having free acidity of 5%) (10 kg) was extracted continuously with methanol (14.1 kg). A methanol phase containing 97% of initial acidity and an organic phase with 0.15% residual free acidity (expressed as oleic acid) were obtained. The methanol phase was fed into a cylindrical reactor controlled by thermostat to 70degreesC and filled with Resindion(RTM: strong cationic resin). During this operation, approximately 70% of the methanol was drawn from the head of the reactor to be then subsequently anhydrified. The esterified methanol phase was added to the triglyceride fraction and subjected to transesterification in the presence of sodium methylate as catalyst, using a tubular reactor working at 80degreesC. At the end, methyl ester compliant with standards according to EN 14214 specification as regards the content of methyl ester, monoglycerides, diglycerides, and triglycerides was obtained.