Solar power is a renewable energy source that uses either sunlight or heat to create usable energy. It’s one of the most promising and abundant energy sources available. A 600 by 600km (400 by 400 miles) area covered in solar modules, can produce our entire planet’s annual energy needs. This could be one small corner of the Sahara Desert.
PV is the most common solar technology, converting sunlight directly into electricity using solar cells within a solar module – also referred to as a solar panel.
CSP uses mirror or lens technology that concentrates sunlight on a receiver to generate steam, which drives a turbine generator that produces electricity.
Solar thermal uses installed devices that absorb the sun’s heat to warm water or heat building spaces.
Passive solar describes the ability to heat buildings from the sun through good insulation and strategic window design.
A solar photovoltaic (PV) cell turns sunlight into electricity by converting light (photons) into electrons. Each cell contains a positive and negative layer that allows sunlight to displace electrons from them to produce DC (direct current) electricity. A solar module incorporates several cells connected together.
A typical solar module (or panel) is roughly 1m x 2m x 40mm. Module efficiency ranges from 15% to 23%, and power ratings can vary from 250 Wp to 700 Wp. Module manufacturers typically warrant performance for 25 to 30 years. It’s not unusual for modules to last 40 years or more.
Bifacial solar panels absorb light from the front and the back of the panel, thus increasing the amount of energy that can be generated from a single module. These panels are produced similarly to traditional solar panels but have a transparent back sheet.
Several solar modules are connected together to form a string or array. For the DC electricity to be used, it is normally converted to AC (alternating current) through an inverter.
To generate optimal energy, solar modules need maximum exposure to the sun’s rays. This is achieved by using racking to either secure them in a fixed position (fixed-tilt) or rotate them to track the sun (tracking).