A single monolithic ceramic substrate has rectangular dimensions with thermal expansion dominant along the length. An inactive ceramic portion substantially surrounds a fuel cell active portion of scalable power. The active portion comprises a plurality of three-layer active structures, each including an electrolyte disposed between a first polarity electrode and a second polarity electrode, the electrolyte layers being co-fired with the inactive ceramic portion, and a first or second gas passage respectively associated with each first and second polarity electrode. The plurality of active structures are stacked in the thickness dimension with alternating polarity such that first polarity electrodes of adjacent active structures face each other with the associated first gas passage shared therebetween and second polarity electrodes of adjacent active structures face each other with the associated second gas passage shared therebetween. The power is scalable according to the number of active structures stacked to define the plurality.