WHAT IS SOLAR PV?
Solar PV is a renewable energy system which uses photovoltaic modules on the roof of a building to convert light into electricity. Voltaic cells are made up of thin layers of semi-conducting material (usually crystalline silicon) which generate an electrical charge when exposed to direct light.

HOW DOES  SOLAR PV WORK?
A Solar PV module is made up of either monocrystalline or polycrystalline cells which consist of two or more thin layers of semi-conducting chemically treated silicon materials. The chemicals react when light hits the cell, creating an electric field across the layers, producing a direct current. The greater the light intensity, the greater the flow of electricity. This direct current (DC) is then fed into an inverter which changes it into a usable alternating current (AC).

WHAT'S THE DIFFERENCE BETWEEN SOLAR THERMAL AND PV?
As previously mentioned, Solar PV systems use energy from the sun to generate electricity with roof mounted modules. Solar Thermal employs roof mounted collectors to absorb energy from the sun. These collectors are usually connected to the lower coil of a twin-coil cylinder via a sealed circuit containing a special glycol/water solution. The pump in the system circulates the heated fluid from the collector to the cylinder, where the stored water is heated for use in the home.

WHAT HAPPENS WHEN THE WEATHER IS CLOUDY OR COLD?
Solar PV uses light to generate electricity, so the modules still work when it is cloudy, although when it is overcast they are less efficient. When it is slightly overcast, the panels may produce as much as half the power they would in sunny conditions. When the sky is heavily overcast, this could reduce further. Temperature is less important than how much light there is. What’s more, a clear cold day is perfect, because PV modules operate better at cooler temperatures.

WHAT IS THE EXPECTED LIFESPAN OF GRANT SOLAR PV?
Solar PV modules should be expected to last at least 25 years, since there are no moving parts. The modules have a twenty-five year performance guarantee.

CAN I SELL THE ELECTRICITY I PRODUCE BACK TO THE ENERGY SUPPLIER?
Most electricity suppliers will pay for power fed into the Grid (feed-in) from domestic Solar PV systems. The easiest way to do this is by signing up to a ‘Buy Back’ or ‘Feed-in Tariff’ scheme with your power supplier. There are two main types of tariff available:
Generation: You are paid for all of the electricity that your solar PV system generates even if you consume it in your home.
Export: You are paid for just the electricity that is exported back to the Grid and not for any electricity you have consumed.