Stand alone PV systems are not connected to the grid. Stand alone systems are set up so that you use the electricity produced by the PV system directly. In order to take full advantage of the electricity produced, it needs to be stored. For this reason, a stand alone system will commonly include battery storage. For further considerations on battery storage, including storage for electricity storage from a wind turbine please see: Should I choose to add batteries instead of getting gridconnected?
Stand-alone PV systems are very useful where there is no electrical grid connection (e.g. in the developing world) and also for applications such as street lighting, traffic signs etc. For further information on the applications of stand-alone solar PV systems, and PV systems in general, go to Solar Electricity Applications.
Concentrating solar thermal systems for electricity generation
Concentrating solar thermal systems for electricity are used to convert solar heat into electricity (as opposed than photovoltaics which directly converts light energy into electricity). A system of concentrators focus a large amount of solar heat energy onto a small area. As a result, this small area is heated to a very high temperature and the heat is used to drive a steam turbine (or similar heat engine) which is connected to an electrical generator.
Concentrating solar thermal systems for electricity generation are encountered at large scales, i.e. sizeable installations for power generation occupying large spaces.
This type of technology is suitable in very hot climates and examples are most common in Meditteranean Europe, Spain and in Northern Africa.
For more information, go to Solar R & D Information and Resources.