The sun’s light energy can be converted directly into electricity in a single process using Photovoltaic (PV) cells, otherwise known as solar cells. A PV cell is a thin plate of light sensitive material made primarily of silicon, the second most abundant element in the earth ‘s crust, and the same semiconductor material used for computers.
Solar panel materials
When the silicon is combined with one or more other materials, it exhibits unique electrical properties in the presence of sunlight. Electrons are excited by the light and move through the silicon. This is known as the photovoltaic effect and results in direct current (DC) electricity.
The solar module consists of the silicon semiconductor surrounded by protective material in a metal frame. The protective material consists of a transparent silicon rubber or butyryl plastic (commonly used in car windscreens) bonded around the cells, which are then embedded in ethylene vinyl acetate. A polyester film (such as mylar or tedlar) makes up the backing. A glass cover is used to protect the panel from the elements.
PV cells are linked together
Many PV cells are linked together to create a standard PV module, which in turn are linked together into a PV array. PV modules have no moving parts, are virtually maintenance-free although they should be kept clean and clear of shading, and have a working life of 20 -30 years.
DC to AC inverter
The PV array produces direct current (DC) electricity. An “inverter” is used to convert the DC to alternating current (AC), so the power is the same as normal grid power and can be used in household appliances. The inverter is a box of electronics, similar to a computer.
What is a solar power system?
The sun delivers a free and environmentally sustainable source of energy to the Earth. Photovoltaic modules, or solar panels, convert radiation from the sun into electricity. Solar panels have no moving parts and can easily be fixed to a school’s roof.
How do grid-connected solar power systems work?
Solar panels produce direct current (DC) electricity which is transformed into 240 Volt alternating current (AC) electricity by an inverter, to run standard electrical equipment and to match the electricity grid power supply. Electricity produced by a grid-connected solar power system will first be used to run equipment in the school, and any excess output will be exported onto the electricity grid.