Infrastructure refers to the structures required to make a system work. Roads, airports and train tracks, for example, are the infrastructure to our transportation system. Our current electrical grid is the infrastructure for our electric supply system in most developed areas of the world. But solar requires only the panels and a storage medium, usually a battery. We have a vacation cabin in the upper midwest that uses both solar and wind power. The entire system fits on, inside and behind our cabin in the form of panels on the roof, a tower and wind turbine in the field, and batteries and electronics in the utility room. By most standards, this does not even constitute a infrastructure since there is no structure connecting it to other locations. Some homes use what is called a, "Utility Intertie," type solar system. In this case, they have the same basic equipment we do, minus the batteries, but the output is actually connected to the homes circuit panel, and thereby to the rest of the utility grid. Any excess the solar produces is sent back out to the grid. It is generally used up at the neighbors house, with the solar producing home getting a credit from the power company, and the nieghbor paying their usual electric bill. This reduces the amount of power the power company has to feed into the grid. So again, there really is not any specific solar power infrastructure, it simply uses what is already available, our existing electrical grid.