Solid Oxide Fuel Cells (SOFC) are typically produced using organic solvent tape casting of one layer (electrolyte, anode or cathode) followed by deposition of the other layers by complex methods such as physical vapour deposition. Our aim is instead to use aqueous tape casting, followed by co-sintering. These are less costly processes, which causes less CO2-emissions, but co-sintering is a critical step. Both shrinkage and thermal expansion must be matched, and of course also the sintering temperature. Using water-based tape casting we have demonstrated co-sintering of NiO/YSZ-anode with 30% porosity and dense YSZ-electrolyte, in planar and tubular shapes. We have also shown that tape casting is a suitable prototype method for tubes. On-going work aims at increasing the porosity and decreasing the working temperature of the cell.