The plate methanol steam reformer (PMSR) designed to enhance its performance is connected with proton exchange membrane fuel cells (PEMFC) considered as a bright future power source. The influences of height and width of transverse ribs, and heating temperature of PMSR were investigated on thermal flow fields, hydrogen yield, methanol conversion, and estimated cell net power of PEMFC. The outcomes show that only heating temperature of 250 degrees C can meet this requirement that the CO concentration lower than 10 ppm can sustain PEMFC operation, so the effect of transverse rib height and width is discussed at heating temperature of 250 degrees C. Compared to the traditional PMSR, a PMSR with the transverse ribs of 1.5 mm height and 4 mm width improves the conversion of methanol up to 19.58% and the hydrogen yield up to 57.23%. The PMSR installing the transverse ribs with 1.125 mm height and 4 mm width enhances the estimated cell net power output of a PEMFC up to 14.20%. The ribs installed in the reformer channel can effectively enhances the conversion of methanol and hydrogen yield of a PMSR and the estimated cell net power output of a PEMFC compared with the traditional PMSR. (C) 2018 Elsevier Ltd. All rights reserved.