Supercritical water reforming of glycerol was studied in a tubular fixed-bed reactor using a Ru/Al2O3 catalyst, and was compared with our previous study using a Ni-based catalyst, with the aim of enhancing the performance of a global process designed under energy self-sufficient conditions. Relatively high glycerol concentrations of up to 25 wt.% and temperatures from 500 to 800 degrees C were tested. Glycerol conversion was very high (>99%) at temperatures of 600 degrees C and above, but low at 500 and 550 degrees C (<50%) using the Ru/Al2O3 catalyst. The gas product (dry basis) was mainly CH4 and CO2, while H-2 production was quite low, against expectations. Under the same operating conditions, the behavior of the catalysts is quite different as the Ni catalyst promotes H-2 production much more than the Ru catalyst. A detailed discussion is provided on our results and those of previous studies using the Ru/Al2O3 catalyst, thus acquiring more insight into the catalyst behavior. The Ru catalyst showed a large increase in its crystalline phase after testing, although the oxidation state of ruthenium did not change. (C) 2015 Elsevier Ltd. All rights reserved.