How PV solar panels work?

PV (photovoltaic) solar panels use rows of solar cells made of semiconductor material.

There's nothing more powerful than when a PV's time has come.

Chemistry reacts with sunlight produces an electric current that’s captured.

Electrons are distributed, stored with battery storage, or sold to the National Grid.

Solar cells consist of two ultra-thin layers of silicon.

Higher the intensity of sunlight, the greater the flow of electrons.

This process is called the photovoltaic effect.

1. Solar cells have a thin layer of anti-reflective coating to reduce light reflection.

2. The top semiconductor layer, or ‘N’ type layer, is doped with small amounts of phosphorus. A phosphorus atom replaces almost every thousandth silicon atom. This reaction creates free-moving negative charges.

3. The base semiconductor layer, or ‘P’ type layer, is doped with minuscule amounts of boron so that a boron atom replaces almost every millionth silicon atom. This reaction creates free-moving positive charges called holes.

4. When both the ‘N’ and ‘P’ type layers are placed close together. The positively charged holes and the negatively charged electrons are attracted to each other.

Moving into their respective neighboring layer, they cross a boundary layer called the p-n junction.

This movement of negatively and positively charged particles generate a strong electrical field across the p-n junction. When sunlight strikes, the electron particles, and the aggregate particles separate.

This creates a voltage of around 0.5V.

5. The voltage flow pushes electrons, or direct current, to contacts at the front and the back of the cell, where it is conducted away along with the wiring circuitry that connects the cells.

Photovoltaic cells are silicon, which the main component of quartz sand and, after oxygen, and the second most common element in the Earth’s crust.

A typical PV solar cell has an efficiency no more significant than 15%, as only a portion of the sunlight energy spectrum can convert into electricity.

If this seems off-putting, please bear in mind that a gas power station has an energy conversion efficiency of only 35% and that 70% of the electricity generated lost during long-distance transmission.

This is why self-generation is better at reducing CO2 emissions.

As an individual solar cell only generates a low voltage, a number of cells are connected together.

This forms a solar panel that generates anything between 180-320 kWp.

The solar panels are then connected together to form a PV solar array.

The solar panels are best installed at an angle between 30 and 50 degrees.

South-facing, but southeastern and southwestern facing systems increase efficiency.

Free from shading during the daytime hours is essential.

PV solar outputs are measured in kW (kilo Watts peak).

DC power is converted into AC.

Performance is typically 950 kWh (Scotland) and 1,350 kWh (South England) of power annually for every 1kW installed.

System sizes range from 1kW -5kW for domestic installations.

On-grid connected photovoltaic systems are the most common as it makes use of the existing mains electricity system. Simpler in design and easier for our MCS solar panels installers to fit than an off-grid system. The electricity produced during daylight hours is either used by the homeowner, or if surplus to requirements, is fed back into the grid via an export meter, or purchased from your utility company.

At night, or on dark days when the panels do not produce enough power, electricity will be supplied automatically from your existing import meter. You will be able to apply for the feed-in tariffs with this type of installation.

Power can be stored in a bank storage device or surplus sold through an export tariff.

Stuart Lovatt 2011-05-27