An Introduction to Solar Electricity
The sun provides more energy in one hour than the world’s inhabitants consume in a whole year. Solar panels harness this powerful, clean, inexhaustible and free resource by converting energy from the sun into electricity for homes, businesses and organisations wanting to reduce their carbon emissions, save on ever-increasing energy bills and reap the financial rewards of a sound long-term investment.
Nonetheless, solar energy remains an underexploited resource in the United Kingdom, which continues to derive the majority of its energy from increasingly expensive and environmentally harmful fossil fuels such as gas and coal.
The links on the left give you all the information you need to help you make the decision on whether solar electricity is right for you.
How is Solar Electricity Generated?
How do solar panels work?
Simply put, solar electricity is generated by panels containing cells which convert sunlight into energy. This energy is generated through the use of photovoltaic technology. Photovoltaic (PV) is a fusion of two words: ‘photo’, meaning ‘light’ and ‘voltaic’, which relates to the production of electricity.
Photovoltaic cells are made of materials called semiconductors (usually silicon, itself a highly sustainable material). When light hits the PV cell, electrons become dislodged from the atoms in the semiconductor. The current which results from the flow of these electrons is then captured and used as electricity.
A common misconception is that the climate of the United Kingdom makes it unsuitable for the generation of solar energy. This is misleading, however, because photovoltaic panels do not require bright sunlight in order to function; they simply require light in general, and while bright sunlight is ideal, they can still generate electricity even on cloudy days.
Solar Cell Technical Diagram
What are the different types of solar photovoltaic cells?
There are 4 main types of Solar Photovoltaic cell currently available in the United Kingdom, with varying costs and efficiency (the rate of conversion of sunlight to electricity):*
Monocrystalline silicon - Typical efficiency 15%. One of the most effective PV cells currently available on the market, and consequently among the most expensive they are cut from a single silicon crystal.
Polycrystalline (or multicrystalline) silicon - Typical efficiency 13%. Although cheaper to produce and slightly less efficient than monocrystalline cells, polycrystalline cells are still cost-effective, they are made from a number of smaller silicon crystals which are melted or recrystallised.
Amorphous/thin film silicon - Typical efficiency 7%. One of the least efficient cell types on the market, and consequently the cheapest. Amorphous cells work well at lower light levels and can even generate electricity from bright moonlight, they are made from non-crystalline silicon and transferred as a flexible film onto another surface such as glass.
Hybrid silicon - Typical efficiency 18%. The most expensive PV cell type available on the market, but also the most efficient, it uses a combination of monocrystalline and amorphous cells for maximum efficiency.
*NB - The precise efficiency of PV panels also depends on factors such as roof orientation and inclination, and amount of shade coverage. It also must be noted that a 4kW solar array will produce 4kW regardless of the type of cells used (however the physical size may be larger using a less efficient technology).