Complex sentence: SOFC stacks with planar geometry require on the order of an hour to be heated to light-off temperature micro-tubular fuel cell design geometries promise much faster start up times, typically on the order of minutes.
Split into simpler sentences: SOFC stacks with planar geometry require on the order of an hour to be heated to light-off temperature. Micro-tubular fuel cell design geometries promise much faster start up times, typically on the order of minutes.