Solar Electric Panels

Solar electric panels, also known as photovoltaic solar panels, PV solar panels or simply solar panels, have been around for about sixty years. As the technology of solar electric panels has advanced over recent years they are now seen as one of the principal future sources of alternative energy.

They work by absorbing sunlight and converting it into useful energy. The panels are made up of solar cells (photovoltaic cells), arranged in a grid, which collect the sun’s rays during daylight hours and convert them into electricity.

What are solar electric panels made from?
The solar cells, which are the active part of solar panels, are traditionally made from crystalline silicon and gallium arsenide. However, there are now also types of panel made from amorphous silicon alloy. Amorphous silicon solar cells can be used in panels that are more durable, efficient and thinner than crystalline versions.

How do solar electric panels work?
Solar panels collect solar radiation from the sun and converts the sun’s energy into electricity. The solar cells within the panel function in a similar way to semiconductors. The energy generated from light photons hitting the surface of the solar panel knock electrons out of their orbit and releases them. The electric fields in the solar cells pull these free electrons in a directional current to the metal contacts in the solar cell which can generate electricity. The greater the number of solar cells in a panel, the greater the electrical output the solar panel can produce.

How much power do solar electric panels produce?
The efficiency of a solar panel, and how much energy it produces, depends on the climate, weather and number of daylight hours of the location where it is installed. Arid climates with continuous sunshine are ideal for solar panels. They will produce most energy when exposed to direct sunlight in clear skies but will also produce a reduced amount under cloudy skies. All PV Solar Panels are affected by heat. The hotter the solar panel, the lower the power output (20% to 40%). This means that power generation can be higher in winter than summer despite the fact that the sun is lower in the sky.

The maximum power a solar panel can produce and the actual power it delivers are not at all the same.

Most PV solar panels are labelled with their peak power output - this is the maximum power (measured in Watts) which that panel can generate in full sunlight. A panel rated at 180W it will perform up to that level in the brightest sun light (1000 watts per square metre). Work out the power produced by finding out the number of ‘peak sun hours’ your location receives each day, then multiply the watt rating of the solar panel by the number of peak sun hours. For example 180W x 8 hours =  1.44KwH. Clearly sun hours will vary by season with the lowest being in the winter.

What are the advantages of solar electric panels?
The main advantage of solar panels is that they are a source of renewable energy. Solar panels are also non-polluting and cause no harm to the atmosphere. Once a solar energy system has been installed the householder benefits from the fact it is a free energy source. Solar cells require very little maintenance as they have no moving parts and can last a lifetime.

What are the disadvantages of solar electric panels?
Solar panels are not cheap to purchase and have installers fit. The savings incurred by having a solar energy system installed in the home will accumulate over 10 to 15 years and eventually repay the cost over time. Government grants are available to encourage the fitting of renewable energy sources for your home.