There isn't a lot of difference in the way a commercial grid-connected solar power system operates when comparing to one used for a residence. If you require power at the same time as when it is being produced (ie. during the day) it will serve your needs immediately. And if you don't use the power produced, you will receive credits from your electricity retailer because you would be supplying that extra electricity to them (instead of using it).
Solar power can be used to power three-phase appliances.: You can have three inverters, one connected to each phase, or a three-phase inverter.
Solar panels are mounted on the roof of a building or on a ground mount structure.