Solar water heating
Solar water heating is a well known renewable technology that can be used to provide hot water. Water heating systems use pumps or fans to circulate liquid through solar collectors to a hot water cylinder. A common solar heating collectors design is a glazed flat-plate design with water being fed through pipes warmed by the sunlight. Other options include evacuated glass tubes for high collector efficiency, and unglazed panels for applications which do not require high temperatures, such as swimming pool heating. Systems are generally roof-mounted and south facing (in the northern hemisphere).
Solar photovoltaic electricity generation
The process of converting light (photons) directly to electricity (voltage) is known as photovoltaics (PV). When photovoltaic materials absorb sunlight the solar energy knocks electrons loose from their atoms, allowing the electrons to flow through the material to produce electricity. Photovoltaic material is used to build solar cell, whic are usually packaged in photovoltaic modules (also known as solar panels). Modules can be grouped together and connected to form a photovoltaic array.
Solar photovoltaics is already used to power a wide range of things from spacecraft to parking meters and calculators. PV is now increasingly used to generate electricity locally for both industrial and domestic use and to feed power into the electricity grid. Until recently photovoltaics have mainly involved relatively expensive silicon semiconductors but new non-silicon options are an exciting growth area. The technology is constantly evolving with research currently taking place in areas such as organic polymer-based photovoltaics (as developed in our Advanced PV Challenge), putting thin film photovoltaic material on flexible substrates, and photovoltaic coatings for rolled steel cladding and roof products.
Solar thermal electricity generation
Solar thermal electricity systems (sometimes referred to as concentrating solar power systems) harness the sun’s heat with mirrors to warm a thermal energy storage medium such as oil, molten salt or air. The stored thermal energy is used to generate steam to power a steam turbine that produces electricity. High temperatures are required for the system to be effective, therefore high and reliable levels of direct sunlight are required to make such concentrating solar systems viable. Unlike photovoltaic systems, the ability to store heat which can be converted to electricity at a later time allows for some flexibility between supply and demand.