Yes there are, Solar Photo Voltaic (PV) and Solar Thermal
PV panels produce electricity and thermal panels produce hot
water
PV cells are made from layers of semi-conducting material,
usually silicon. When light shines on the cell it creates an
electric field across the layers. The stronger the sunshine, the
more electricity is produced. Groups of cells are mounted
together in panels or modules that can be mounted on your roof.
Solar water heating systems use solar panels, called collectors,
fitted to your roof. These collect heat from the sun and use it to
heat up water that is stored in a hot water cylinder. A boiler or
immersion heater can be used as a back up to heat the water further
to reach the temperature you want
Both systems will ultimately provide 'FREE' energy however,
installation costs can be high.