Solar PV (photovoltaic) panels convert 15-20% of the sunlight falling on them directly into electricity which can be used by any electrical appliance. Even in the UK climate which typically has overcast sky the PV modules can still make a significant contribution. Software modelling can be used to calculate the expected energy capture over the period of a year taking into account location, orientation and shading.
Solar thermal systems convert the sun’s rays into hot water. They are more efficient than solar PV systems at converting the sun’s rays into useable energy, but hot water has less applications than electricity. The heat produced can be used to supplement conventional heating systems and offer a significant fuel cost saving even on cloudy days.