What is Solar?

What is Solar Energy?

Solar energy has been powering devices from calculators to satellites since 1958. Solar power is generated from the sun, through either its heat or light. On average, every square metre of the Earth’s surface receives 164 watts of solar energy every hour. That is enough to power a light bulb.

Solar facts:

“If just one percent of the Sahara Desert was covered in solar panels, we could generate enough electricity to power the whole world”

“Every hour, enough sunlight falls on to the Earth’s surface to generate enough electricity for the world’s current requirements for a year”

What is Solar PV?

A photovoltaic cell is made of one or two layers of a semi-conducting material such as silicon. One layer (p-type) has holes, where electrons should be, which gives it a positive charge. The other layer is negatively charged because it has spare electrons (n-type).

So, electrons from the n-type are attracted to the holes in the p-type and they cross through a boundary layer called the p-n junction.

When sunlight hits the cell in the form of photons, its energy knocks the electrons loose. As these move from one cell to another, they pass through a boundary layer called the p-n junction. This flow of electrons is an electrical current, known as Direct Current (DC), which then passes through a clever box, called an inverter, to become Alternate Current (AC) at 240 volts.  This is the type of electricity that we use at home.

What is a Solar PV Cell?

Solar PV cells are grouped together to create a solar panel, which has a protective glass coating.  Solar panels are combined and work in tandem to create a solar array, to maximise your generation of power.

A PV cell’s power output is measured in kilowatt peak (KWp) which defines the amount of energy generated in full sunlight.

There are many advantages to solar PV panels:

• High reliability
• Longevity – solar panels will last for decades and are guaranteed for 25 years
• Silent operation, as there are no moving parts
• Continued performance, even when cloudy or raining

The difference between Solar PV and Solar Thermal Energy (STE)

Solar PV uses light to create electricity where as Solar Thermal uses the heat of the sun to warm water. This can then be used for domestic hot water, in heating systems or to create steam which, in turn, powers turbines to create electricity.