I worked for the county government and they had ice melt systems and then for a public school district and two schools had them. They work very well and do not use a lot of energy. They keep the sidewalk just above freezing and in our western NY climate that is only a few to maybe 30 degrees warmer than outdoor temps for most of the winter.
The school used boiler water that warmed a heat exchanger for the ice melt systems that used glycol. The ice melt piping was cast into the concrete sidewalks and steps and there was extruded polystyrene foam below the sidewalks to limit heat transfer to the ground. It worked very well, not much energy was used and there was never a flake of snow on the surfaces. Compared to paying the staff to shovel and salt, especially considering the damage done to concrete by salt, and it was a money saver. Also, when thousands of students arrived in the morning, by the time they walked over the heated sidewalk and up the heated stairway to the main entrance, their shoes were fairly clean. That lowered custodial costs and reduced wear and tear on the floors. The ice melt systems were one of the best things I ever installed at the school.
My son put piping in his sidewalk from his house to this garage, but has not bought the equipment to finish the installation.