Solid oxide fuel cells were fabricated with a 5 mu m thick film of Ce0.9Gd0.1O1.95 electrolyte, supported on a NiO-YSZ cermet anode with a La0.6Sr0.4Co0.2Fe0.8O3 cathode, for operation at temperatures below 700 degrees C. The performance for power generation was studied with externally reformed methanol fuel or with methanol/water vapour fed directly to the anode. The open-circuit voltages of 0.7-0.8 V were lower than the theoretical potential as a result of electronic permeation across the electrolyte film. Maximum power outputs of 126, 65 and 32 mW/cm(2) were obtained at 650, 600 and 550 degrees C respectively, using the externally reformed fuel. With direct methanol fuel the maximum power output was lower at each temperature by 16, 38 and 53%, respectively. The latter result at 550 degrees C was due to the poor internal reforming of methanol to hydrogen at the anode. The addition of Pd to the anode promoted the internal reforming at 550 degrees C: the maximum power output was similar to the previous result with externally reformed fuel and 45% lower with direct methanol fuel.