AbstractPlanar solid oxide fuel cells (SOFC) with CuO/gadolinium‐doped ceria (GDC) supporting anode were produced and tested in H2 and in CH4/CO2 mixture at 650 °C. The electrolyte densification at 900 °C was promoted by compressive strains induced by larger anodic thickness. The reduction behaviour of CuO/GDC anodic powders was preliminarily evaluated. The electrochemical measurements showed an increasing power density with the anode thickness (from ≈500 μm to ≈1.4 mm) reaching a maximum value of 227 mW cm−2 at 650 °C in pure H2. Power density of 29 mW cm−2 was measured in wet CH4/CO2 biogas mixture at 650 °C. Catalytic activity measurements towards methane dry reforming showed limited conversion at all investigated temperatures, this suggesting that the actual anodic reaction is the methane combustion. Scanning electron microscope observations and energy dispersive X‐ray analyses of the cell tested in CH4/CO2 mixture did not show any carbon deposit, thus pointing out that the Cu/GDC cermet can be considered a stable and reliable anodic substrate for IT‐SOFC fed by CH4/CO2 mixture.