PV Systems - Energy Assessors London

Electricity is produced from sunlight through a process called solar photovoltaics. Photovoltaic cells are made of semi-conducting materials, so when the sunlight strikes, it is converted into electricity.

The solar cells are made of several thin layers of silicon. When sunlight strikes, the electrons within the cell are knocked loose. By the absorption of a photon (light particle), the negative electron gets shunted away from the silicon atom, and a positive ‘hole’ remains. The freed electron and the positive hole together are neutral. Therefore, to be able to generate electricity, the electron and the hole need to be separated from each other. This is done by giving layers within the cell opposite charges, so that the freed electrons cannot return to the positively charged holes. When the electrical contacts on the front and rear are connected through an external circuit, the freed electrons can only return to the positively charged holes by flowing through this circuit, thus causing electricity to flow. This means that the greater the intensity of light (larger number of photons), the greater the flow of electricity.

Even if the sky is overcast, PV still produces electricity. This is because PV cells not only use direct sunlight, but also diffuse solar radiation, which is light that has been scattered by dust and water particles in the atmosphere. Obviously the amount of useful electricity generated is proportional to the intensity of light energy which falls into the conversion area. However, you can still have an electricity supply even without the sun!

To determine the PV electricity generation potential for a particular site, it is important to assess the average total solar energy received over the year.

Despite its advanced technical capabilities, a PV system will not generate electricity at night, but the system is able to store collected energy in a battery for use during non-daylight hours.

Our systems offer an efficient and reliable power source to where it is needed most. Aside from high performance, our systems offer a combination of economic and environmental benefits to the user, making it the optimal power solution for homes, commercial and public buildings.

Environmentally friendly: The PV modules are made out of silicon which is entirely benign, and available in abundance. No noise pollution or harmful gases are emitted during the operation.

Immediately available: PV utilises the most abundant energy source on the planet – the sun.

No barriers to installation: PV is not affected by ‘Nimbyism’ or affected by planning delays.

Minimal maintenance: PV has no moving components and is virtually maintenance free.

Flexible: PV systems can be incorporated into all types of building, and retrofitted on existing roofs, or as part of the building envelope at construction stage. It can be curved and shaped to the building design.

Cost effective: In grid locations where grid connection is too expensive.

Reduces energy bills: Having a solar roof provides you with a power source that can be used to augment your grid connected electricity supply subsequently reducing your electricity bills. In addition, having PV as an energy resource increases your awareness of electricity use and encourages more efficient energy behaviour. This in turn leads to lower energy bills.