NOVELTY - A feedstock having carboxylic acid and triglyceride is converted into a biodiesel by performing esterification including mixing the feedstock with an alcohol to produce a reactant mixture, contacting the mixture with an acid catalyst, and applying radio frequency or microwave energy to one of the above reactants to convert carboxylic acid to biodiesel; and performing transesterification to convert triglyceride to biodiesel.    USE - Used for converting a feedstock having carboxylic acid and triglyceride into a biodiesel.    ADVANTAGE - The process results in higher process rates and/or higher conversion levels. It increases yield and reduces reaction time over existing biodiesel transesterification and esterification techniques.    DETAILED DESCRIPTION - Conversion of a feedstock having carboxylic acid and triglyceride into a biodiesel using esterification and transesterification, includes performing esterification including mixing the feedstock with an alcohol to produce a reactant mixture, contacting the reactant mixture with an acid catalyst, and applying radio frequency (RF) or microwave energy to one of the carboxylic acid, the alcohol, the catalyst, the mixture and their combination to convert the carboxylic acid to the biodiesel; and performing transesterification to convert the triglyceride to the biodiesel.    INDEPENDENT CLAIMS are also included for the following:    (1) converting a triglyceride to an alkyl ester and glycerol using transesterification, comprising mixing the triglyceride with an alcohol to produce a reactant mixture; flowing the reactant mixture over a heterogeneous catalyst with a relative velocity of greater than or equal to 0.005 m/second to obtain high reactant shear at a reactant-catalyst interface; and producing alkyl ester and glycerol; and    (2) converting a carboxylic acid to an alkyl ester using esterification, comprising mixing the carboxylic acid with an alcohol to produce a reactant mixture; contacting the reactant mixture with an acid catalyst; and applying RF or microwave energy to one of the carboxylic acid, the alcohol and/or the catalyst to produce the alkyl ester.    DESCRIPTION OF DRAWING(S) - The figure shows biodiesel transesterification production.